Biopolymer Workshop Kenya 2013 - Proceedings by PoliMaT

BIOPOLYMER WORKSHOP KENYA 2013 Proceedings Harnessing the power of biopolymers for improving human wellbeing and enhancing global competitiveness Nairobi, Januar y 27- 30, 2013

contents

THE BIOPOLYMER WORKSHOP IN KENYA 2013

HARNESSING THE POWER OF BIOPOLYMER MATERIALS AND TECHNOLOGIES

MATERIALS AND TEHNOLOGIES FOR NEW BUSINESS OPPORTUNITIES

FORGING NEW DIPLOMATIC BONDS THROUGH SCIENCE AND TECHNOLOGY

THE PLENARY LECTURERS AT THE BIOPOLYMER WORKSHOP IN KENYA 2013

THE PLENARY LECTURES AT THE BIOPOLYMER WORKSHOP IN KENYA 2013

I. POLICY IMPLICATIONS, SCIENCE AND TECHNOLOGY

II. IDENTIFICATION OF NEEDS

III. BIOPOLYMER SCIENCE AND TECHNOLOGY

CE POLIMAT – CENTER OF EXCELLENCE FOR POLYMER MATERIALS AND TECHNOLOGIES

Edited by: Maja Berden Zrimec and Alexis Zrimec Graphic design by: Alenka Paveo Printed by: Ednas Print d.o.o. All rights reserved. No part of this report may be reproduced in any form in any electronic or mechanical means (including photocopying, recording or information storage and retreival) without permission inwriting from the Center of Excellence PoliMaT. ©CE PoliMaT Published in 2013 by the Center of Excellence PoliMaT, Tehnološki park 24, SI-1000 Ljubljana, Slovenia, EU en.polimat.si

The Biopolymer Workshops Approach • Joint initiative of the Global Biopolymer Network • Focus on new generation of young scientists and engineers • Interface of science, industry and policy • Formation of project ideas

CIP - Kataložni zapis o publikaciji Narodna in univerzitetna knjižnica, Ljubljana 577.11(082) BIOPOLYMER Workshop (2013 ; Nairobi) Harnessing the power of biopolymers for improving human wellbeing and enhancing global competitiveness : workshop proceedings / Biopolymer Workshop 2013, January 2731, 2013, Nairobi, Kenya ; [organized by Center of Excellence PoliMaT, Ljubljana, Slovenia and Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya] ; editors Maja Berden Zrimec and Alexis Zrimec. - Ljubljana : Center of Excellence PoliMaT, 2013 ISBN 978-961-269-991-8 1. Gl. stv. nasl. 2. Berden Zrimec, Maja 3. PoliMaT, Center odličnosti polimerni materiali in tehnologije (Ljubljana) 4. Jomo Kenyatta University of Agriculture and Technology (Nairobi) 266337792

addressing specific local needs • Sharing of state-of-the-art biopolymer knowledge • Formation of multi-disciplinary teams working on concrete topics • Involvement of international and local mentors for student orientation

PREFACE

THE BIOPOLYMER WORKSHOP IN KENYA 2013

ou hold in your hands the Proceedings

The main goal of the first Biopolymer Workshop,

of the 1st BIOPOLYMER WORKSHOP,

taking place in Kenya in 2013, was to learn, network

published by the Center of Excellence

and collaborate in addressing the challenges of

PoliMaT (CE PoliMaT). The Proceedings

sustainable agriculture, health and technological

include a selection of lectures presented

development in Sub-Saharan Africa through the

during the Workshop, held on 27-30 January 2013 in

use of biopolymers. The material presented in this

Nairobi, Kenya.

Proceedings was the basis for group work that resulted in five project ideas, the formation of

Biopolymer Workshops bring experts from the

dedicated teams to work on the projects and the

Global Biopolymer Network to local environments

creation of roadmaps for their future activities.

and integrate them with local R&D and industrial competencies thus initiating collaboration and

The Proceedings start with introductory contributions

partnerships. By participating in the Workshops,

by Mateja Dermastia, the CEO of CE PoliMaT,

universities, government officials, industry

professor Mabel Imbuga from Jomo Kenyatta

representatives and the interested public – as

University of Agriculture and Technology, and

the Workshops’ key actors – fuel innovations

professor Calestous Juma from Harvard Kennedy

and establish suitable framework conditions for

School, followed by short CVs and lectures from

strengthening the biopolymer innovation system.

speakers.

Teams of international and local mentors work

The organizing team would like to thank those who

with Biopolymer Workshop participants to

made the first Biopolymer Workshop in Kenya a story

identify challenges, value chains, addressable

of success: the participants for their enthusiasm,

technological problems and policy issues, and build

the Jomo Kenyatta University of Agriculture and

roadmaps to solutions.

Technology (JKUAT) for hosting the Workshop, the international team of experts and mentors from

Through lectures, case studies, panel discussions

CE PoliMaT (Slovenia), JKUAT (Kenya), the Harvard

and intensive group work, Biopolymer Workshops

School of Engineering and Applied Sciences (SEAS,

lead to outlined collaborative project ideas that

USA), Harvard Kennedy School (HKS, USA), VDI/VDE-IT

address specific needs of different industrial,

(Germany), the Polymer Competence Center Leoben

social and consumer segments, and a clear

(PCCL, Austria), the Austen BioInnovation Institute in

action plan for their further development into well

Akron (ABIA, USA), Educell Ltd. and MikroCaps Ltd.

defined project proposals. In addition, dedicated

(both Slovenia) for their input and guidance, and the

international teams that make up the core of future

sponsors, Econyl ® (Aquafil Group), Kračun Ltd., and

partnerships in collaborative projects are formed.

Westminister for their financial support.

INTRODUCTION

Harnessing the power of biopolymer materials and technologies

n today’s global economy, technological advancements and the ability to innovate have become ever more crucial in the quest for competitiveness and productivity. This is especially true for countries with a long-term dependence on exports of limited natural resources, conventional industrial processes and climate challenged agriculture.

Deriving from natural biological and agricultural sources and serving as environmentally friendly substitutes for conventional materials, biopolymers have proven to be an advanced material of the 21st century. Biopolymer research builds on modern-day advancements in chemistry, materials science, biotechnology, Mateja Dermastia CEO of CE PoliMaT http://en.polimat.si/

nanotechnology and other sciences and as such offers a strategic entry point to a variety of advanced technological applications of immediate relevance to agriculture, health, water and environmental management, energy efficiency and value-added industrial production. Biopolymers hold great potential to tackle global challenges and at the same time contribute to the efforts of solving major environmental problems in developing countries. Biopolymer applications emerge from scientific, technological and engineering approaches which require new forms of international science and technology collaboration, proving that simply relying on local resources for new innovations is no longer sufficient. In June 2012 Harvard University and Slovenia hosted the International Conference on Technology and Innovation for Global Development: Schumpeter and Polymer Research. Addressing the conference, former President of Slovenia Dr Danilo Türk stressed that the “optimization of development is possible and that any optimization starts with science, technology and innovation.” A Global Biopolymer Network is emerging under the leadership of the CE PoliMaT, bringing together scientific and technological know-how of developed countries and abundant biological resources as well as young talents from African countries to support new partnerships. The network currently includes the Austen BioInnovation Institute (Akron, USA), the Harvard School of Engineering and Applied Sciences, the Harvard

“ Biopolymers hold great potential to tackle global challenges and at the same time contribute to the efforts of solving major environmental problems in developing countries.”

INTRODUCTION

â&#x20AC;&#x153; The network builds on the strengths of the participating institutions and companies with a focused approach to real-world problems.â&#x20AC;?

Mateja Dermastia is CEO of CE

Kennedy School (Cambridge, USA), the Jomo Kenyatta University

PoliMaT, Slovenia. Ms. Dermastia has

of Agriculture and Technology JKUAT (Nairobi, Kenya), VDI/VDE

more then 20 years of professional

Innovation (Berlin, Germany), CE PoliMaT (Ljubljana, Slovenia) and

experience in the area of enterprise

the Polymer Competence Center Leoben (Leoben, Austria). The

competitiveness, competitiveness

network builds on the strengths of participating institutions and

policies and long-term managerial

companies with a focused approach to real-world problems that

experience in leading public and private institutions. She is an internationally-recognized authority on industrial clusters, innovation and competitiveness policies, strategies and programmes. She has served in various capacities including state undersecretary in the Slovenian government and senior advisor to

can be addressed through appropriate technological solutions involving advanced materials and biopolymers. Upon the suggestion of Professor Calestous Juma, Professor of the Practice of International Development and Director of the Science, Technology, Globalization Project, Harvard Kennedy School, Harvard University, the First Biopolymer Workshop was held on January 27-30, 2013 at the JKUAT in Nairobi, Kenya. CE PoliMaT

the Turkish government. She has

and JKUAT organized the workshop in collaboration with all

served on various international

institutions from the Global Biopolymer Network. The goal of the

expert committees and groups on

workshop was to establish a frontier biopolymer research program

competitiveness, clustering, and

for Africa. The Biopolymer Workshop was focused on current

innovation policies. Ms. Dermastia is

advancements in biopolymer research with implications for

recognized for her extensive advice

industry, public policy and international science and technology

to governments in developed and

cooperation, and was driven by global trends in biopolymers and

developing countries. In addition,

by lessons learned and experience gained from international

she has helped to build expert teams

centers of excellence in the USA and Europe. The workshop

and provide managerial guidance

equipped students, scientists and engineers with skills to identify

on issues related to innovation and

research topics most relevant to the industry, to find industrial

industrial development. Beyond this experience Ms. Dermastiaâ&#x20AC;&#x2122;s profile embodies the triple helix concept with first-hand experience in government, industry and academia. She has worked on international assignments for the EU, the World Bank, the OECD and COMESA. Originally trained in

and international partners, and to identify policy options for strengthening the innovation system in partnering countries. The workshop underscored the role of new ways of international collaboration with an emphasis on the leading role of international networks of research institutes, national universities, and the private sector since in shaping new diplomatic relations

biochemistry, Ms. Dermastia has a

among nations. Slovenia and Kenya are initiating a form of

Masters in Economic Sciences and

science and technology diplomacy based on a commitment to

has obtained executive education

tackling the global challenges irrespective of size and level of

at the Harvard Kennedy School. She

development. The cooperation points to a new future in which

has written extensively on clusters,

science and technology will increasingly become the bond that

competitiveness and innovation.

ties nations together in new diplomatic arrangements.

INTRODUCTION

Materials and technologies for new business opportunities

ll of us at JKUAT University are pleased to co-host the Biopolymer Workshop that is expected to open up new opportunities and address some of our local challenges, all geared at improving the well-being and economic circumstances of our people.

The three-day workshop that is jointly sponsored by JKUAT and CE PoliMaT of Slovenia brings together over 50 participants from various countries in Africa, Europe, and North America. We at JKUAT are always eager to undertake such programs. Applied research and innovation are functions that are of particular interest to both our faculty and students.

Prof. Mabel Imbuga, Vice Chancellor of JKUAT http:/www.jkuat.ac.ke/

For example, there is the problem of plastic bags. In our capital city of Nairobi, over 212,000 tons of plastic are consumed, of which 160,000 tonnes, i.e. 80 percent of all plastic used, are indiscriminately dumped in our Cityâ&#x20AC;&#x2122;s

INTRODUCTION

â&#x20AC;&#x153; The exploitation of biopolymer technologies would open up new business opportunities for our entrepreneurs, mainly in agriculture, health services and waste management.â&#x20AC;?

Prof. Mabel Imbuga is the Vice Chancellor of Jomo Kenyatta

environment that includes over

University of Agriculture and Technology, a Public University in

three million inhabitants. Clearly, the

Kenya, well known for its leading role in Agriculture, Science,

environmental consequences of this

Technology and Innovation in the African Continent. She is a

are catastrophic.

Professor of Biochemistry, with over 33 years of teaching, scholarly and leadership experience. She is the Vice Chairperson of the Inter-University Council of East Africa, a position she assumed in April 2012. Prof. Imbuga has extensive knowledge and demonstrative experience in the higher education system, having

The aim of this workshop is to provide a forum for participants to review current advancements in biopolymer research

grown from a Research Assistant, Assistant Lecturer, Lecturer,

and their policy implications for

Research Scientist, Chairman of Department, Dean, Director as

industry. The exploitation of biopolymer

well as a Deputy Vice Chancellor in charge of Academic affairs.

technologies would also open up

Imbuga is a key resource in strategic management and leadership, with an MBA in strategic management. She is a Pan Africanist and a key reformer in the higher education setup in Africa, having successfully driven a number of key projects,

new business opportunities for our entrepreneurs in the aforementioned areas, mainly in agriculture, health services and waste management.

including strengthening the higher education stakeholder relations in Africa and the recent launch of Pan African University

This workshop is a precursor to the

Institute hub of Basic Science Technology and Innovation (PAUSTI),

establishment of a permanent

housed in JKUAT, Kenya. She is a mover and doer of successful

Biopolymer Center, another STI center

African projects in higher education, resulting in increased access

within the COMESA member states

and transformation of the higher education. She has participated

at JKUAT to be known as the JKUAT

in various forums and key Government seminars as a motivational speaker for upcoming leaders and scientists.

Biopolymer Center (JBC).

Imbuga has over 10 funded projects and 27 publications. She has

It will operate according to the

attracted over 15 international funding for various projects cutting

knowledge and competencies drawn

across various disciplines. She is a member of several professional

from international cooperation with,

associations across the world, a former president of the African

among others, CE PoliMaT of Slovenia,

Women in Science and Engineering (AWSE); immediate former

the Harvard University Kennedy

Director of International Network of Women Engineers and Scientists; she is a member of the Global Consortium of Higher Education and Research for Agriculture (GCHERA) and member of the International Conference of Women Engineers and Scientists (ICWES), Co-Chair of CO DATA - The Committee on data

School, and the Austen BioInnovation Institute in Akron (USA). With the help of the Biopolymer Workshop, JBC will be able to realize our research and

for Science and Technology, Trustee of the Kenya Educational

development goals in biopolymers,

Network, Vice Chair of the Inter University Council for eastern

which will lead to innovations and

Africa and Commissioner of the Commission for University

spin-offs to local and international

Education.

industries.

INTRODUCTION

FORGING NEW DIPLOMATIC BONDS THROUGH SCIENCE AND TECHNOLOGY

cience and technology are being increasingly recognized as central features in international diplomacy. Much of the attention, however, has focused on how major industrialized countries and large emerging nations such as China, India, and Brazil use science and technology to advance their global competitiveness.

One of the most pressing global challenges, though, is how to leverage the power of new knowledge to help address the global economic and environmental challenges. New science and technology diplomacy responses are emerging from smaller industrialized nations working with developing countries.

Prof. Calestous Juma, Director of Science, Technology and Globalization Project, Harvard Kennedy School http://belfercenter.ksg. harvard.edu/project/39/ science_technology_and_

A number of industrialized countries have sought to strengthen science and technology diplomacy in their foreign services. The United States, for example, pioneered in creating an Office of Science and Technology Adviser to the Secretary of State. This office is part of a complex array of agencies that interact on scientific and technological matters on a continuous basis. The players include the American Association for the Advancement of Science, which runs a center that aims to use “science to build bridges between countries and to promote scientific cooperation as an essential element of foreign policy.”

globalization.html

In most diplomatic efforts nations seek to interact through institutions with comparable levels of competence. Decades of appeals through United Nations (UN) conferences to help build scientific and technological capacity in developing countries have yielded negligible results. The United Nations Secretary-General has failed to muster the political support needed to create an office of science and technology adviser. As a result, the UN is generally hobbled when dealing with complex issues involving science and technology. This is particularly critical given the growing recognition of the role of science and technology in most international negotiations ranging from disarmament to sustainable development. New diplomatic leadership on using science and technology to solve global

“ Slovenia and Kenya are inventing a form of science and technology diplomacy that is based on commitment to taking on global challenges irrespective of size and level of development.”

INTRODUCTION

challenges is starting to emerge from smaller nations

Slovenia is working closely with African countries to

working closely with developing country partners. One

build capacity in using scientific advances to solve

of the most inspiring examples is the role of Slovenia in

economic and environmental problems.

leveraging the power of frontier biopolymer research to address global challenges in fields such as agriculture, health, water, and environmental management. Slovenia is a small nation with just over 2 million people.

In June 2012 Harvard University and Slovenia hosted the International Conference on Technology and Innovation for Global Development: Schumpeter and

However, the country has a long tradition of scientific

Polymer Research. As a follow up to the conference,

excellence that precedes its famed chemistry Nobel

Slovenia—through CE PoliMaT—has helped JKUAT

laureate Fritz Pregl. Its diplomatic reach in developing

to establish a Biopolymer Research Programme. The

countries is limited. For example, Slovenia has only

program will focus on how to leverage engineering

one embassy in Africa located in Egypt. But through its

advances in biopolymer research to solve global

center of excellence in polymer research, CE PoliMaT,

challenges in fields such as agriculture, health, and environmental management.

Prof. Juma is an internationally-recognized

JKUAT operates as a thematic hub for basic sciences,

authority on the role of innovation in economic

technology, and innovation for the Pan African

development. He is Professor of the Practice of

University established by the African Union, giving

International Development and Director of the

the program a continental mission. These efforts can

Science, Technology, and Globalization Project

help support the work of the Innovation Council that

at Harvard Kennedy School. He also directs the School’s Agricultural Innovation in Africa Project funded by the Bill and Melinda Gates Foundation and serves as Faculty Chair for the School’s Innovation for Economic Development Executive Program.

was recently established by the 20-member Common Market for Eastern and Southern Africa (COMESA). Addressing the founding workshop, Professor Imbuga underscored the uniqueness of the diplomatic effort. She said Slovenia had brought “together over 50

He co-chairs the High-Level Panel on Science,

participants drawn from various countries in Africa,

Technology and Innovation of the African Union

Europe, and North America.” Equally important, she

and is a member of the judging panel of the

added, was the participation of 26 graduate students

Queen Elizabeth Prize for Engineering.

from the university.

He is a former Executive Secretary of the UN Convention on Biological Diversity, founding

This example illustrates the potential role that smaller

Executive Director of the African Centre for

nations working with developing country partners

Technology Studies in Nairobi and Chancellor of

can have in promoting new science and technology

the University of Guyana. He has been elected to

diplomacy approaches. It underscores the role that

several scientific academies including the Royal

political leadership, international networks of research

Society of London, the US National Academy of

institutes, national universities, and the private sector

Sciences, the World Academy of Sciences, the UK

can play in forging new diplomatic relations among

Royal Academy of Engineering and the African

nations.

Academy of Sciences. Juma holds a DPhil in science and technology policy studies from the University of Sussex, UK.

Slovenia and Kenya are inventing a form of science and technology diplomacy that is based

He has received several international awards

on commitment to taking on global challenges

and honorary degrees for his work on sustainable

irrespective of size and level of development. The

development. His latest book, The New Harvest:

cooperation points to a new future in which science

Agricultural Innovation in Africa, was published in

and technology will increasingly become the

2011 by Oxford University Press. Updates on his work

bond that ties nations together in new diplomatic

are available via Twitter @calestous.

arrangements.

IntRoDUctIon

THE PLENARY LECTURERS AT THE BIOPOLYMER WORKSHOP IN KENYA 2013 Sujata K. Bhatia

Stephen D. Fening

Harvard school of engineering and Applied sciences, seAs, and Harvard Kennedy school of Government, HKs – UsA

Austen BioInnovation Institute in Akron, ABIA - UsA

Dr. Bhatia serves as an Assistant Director

Dr. Fening serves as the Director of

for Undergraduate studies in Biomedical

orthopaedic Devices within the Medical

engineering, an Assistant Dean at Harvard

Device Development center at ABIA. In

summer school, and Associate at Harvard

this role, Dr. Fening drives innovation in

Kennedy school of Government. she

orthopaedic device development within

is a physician-scientist with academic

ABIA and its partners. He previously served

and industrial experience in biomedical

as the Director of sports Health Research

engineering. Dr. Bhatia has academic

at cleveland clinic, where he had a

experience as a faculty member in

joint appointment in the Departments

biomedical engineering and chemical

of orthopaedic surgery and Biomedical

engineering, teaching and advising

engineering. Dr. Fening has undergraduate

biomedical engineering students, developing

and masters degrees in mechanical

visionary senior design projects, and

engineering, a doctorate in biomedical

authoring biomaterials text books. she has

engineering, and a postdoctoral fellowship

industrial experience in medical device and

in orthopaedic biomechanics at cleveland

biotechnology product development, clinical

clinic. His areas of research focus are on

trials management, intellectual property,

cartilage injury modeling and biomechanics

leadership of multidisciplinary teams,

of the knee and shoulder. Dr. Fening was

and industry-academic partnerships. Dr.

awarded the cleveland clinic Innovator

Bhatia serves on panels and committees for

Award in 2008, as well as the “Basic science

national Academy of engineering, national

teacher of the Year” by the Department of

Academy of sciences, and national science

orthopaedic surgery, and a Distinguished

Foundation.

educator by the cleveland clinic.

IntRoDUctIon

Gerd Meier zu Köcker VDI/VDe-It – Germany

public authorities on regional, national and international level, comprehensive experience in strategy consultation, cluster issues, design and management of national and international projects. Besides of his scientifi c work in technical and socio-economic areas, Dr. Meier zu Köcker is deeply involved in various projects dealing with clusters, competitiveness and innovation policy issues. In 2007 he was appointed by the Federal

Dr. Meier zu Köcker is the Director General of

Ministry for economy and technology (BMWi)

the Agency competence cluster Germany,

to take over the management of the Agency

Managing Director at the Institute for Innovation

competence networks. In 2001 he was awarded

and technology, iit Berlin, Head of the Department

by the Lithuanian Innovation Agency for his long-

for International technology transfer within

term support to increase the innovation capability

VDI/VDe-It, and Deputy General Manager at

and competitiveness of Lithuanian sMe. since

VDI/VDe-It. He has long-term experience in

2009 he is the German representative within the

innovation and technology policy, consultation

european cluster Policy Group. Dr. Meier zu Köcker

and communication with policy makers and

is also a member of various Advisory Boards.

andrej Kržan ce PoliMat – slovenia

plastics, biodegradable polymers and plastics, and the use of renewable resources for polymer production. Dr. Kržan is a secretary general & national representative of the european Polymer Federation, and president of the section for Polymers at the slovenian chemical society. He is member of the American chemical society, the central and east european Polymer network, and the scientifi c council of the national Institute of

Dr. Kržan is a senior scientifi c associate at the

chemistry, slovenia. For a number of years he has

national Institute of chemistry and ce PoliMat,

served as expert consultant for Biodegradable

slovenia. His research interests are in environmental

Plastics Programme at Ics-UnIDo, Italy. Dr. Kržan

and sustainability aspects of polymers and

was awarded the France Prešeren Award for

plastics: recycling of waste polymers and

students of the University of Ljubljana.

Gernot Oreski Polymer competence center Leoben, PccL – Austria

Dr. oreski is a senior Researcher at the Polymer competence center Leoben, Austria. His main fi elds of research are polymer physics and testing, polymers for solar energy applications, weathering, aging behavior and aging characterization of polymers. one of the main topics of Dr. oreski PhD work were special properties and aging behavior of common agricultural fi lms.

IntRoDUctIon

Dejan Štefanec ce PoliMat, Mikrocaps Ltd. – slovenia

Dr. Štefanec undergraduate study has been partly supported by a grant from “Jožef stefan” Institute and awarded chancellor’s award of the University of Maribor. His Ph.D. thesis has been awarded with national awards (Krka’s prize, Henkel’s fund). During the doctoral studies, Dr. Štefanec received also a scholarship from the World Federation of scientists. He worked as a researcher in Belinka Perkemija, Ljubljana, and in the year 2010 he joined the center of excellence PoliMat. Dr.

Dr. Štefanec is a cofounder and Head of Research

Štefanec research work has been published

at the company Mikrocaps. He undertook his B.sc.

in several articles and has been presented at

and Ph.D. at the University of Maribor in slovenia.

national and international conferences.

Majda Žigon ce PoliMat – slovenia

nanoparticles, functionalization of montmorillonite particles, homopolymers and copolymers of amino acids and lactide, polymer properties in solution and solid state. she is a member of editorial Boards of journals Acta chimica slovenica and the International Journal on Polymer Analysis and characterization. she was the president of the european Polymer Federation (ePF) in 2006-2007 and national representative to ePF in 2002-2008, president of the section of Polymers

Dr. Majda Žigon is President of the scientifi c

of the slovenian chemical society in 2002-2008,

council of ce PoliMat and full professor at the

president of the central and east european

Faculty of chemistry and chemical technology at

Polymer network (ceePn) in 2012 and is an

the University of Ljubljana, slovenia. Her research

associate member of Polymer Division of IUPAc

interests are in synthesis and characterization

(2012-2013) and IUPAc fellow. Majda Žigon has

of various polymers, polymer composites and

been awarded the France Prešeren Foundation

nanocomposites with clay and metallic oxides,

Award for students of the University of Ljubljana,

synthesis of metallic and inorganic oxide

and the Boris Kidrič Foundation Award.

plenary lectures

THE PLENARY LECTURES AT THE BIOPOLYMER WORKSHOP IN KENYA 2013

Chapter I. POLICY IMPLICATIONS, SCIENCE AND TECHNOLOGY • Key Success Factors of Centres of Excellence, Gerd Meier zu Köcker

Chapter II. IDENTIFICATION OF NEEDS • Value-driven Engineering, Stephen D. Fening and Frank L. Douglas

Chapter III. BIOPOLYMER SCIENCE AND TECHNOLOGY • Medical Devices and Biomaterials for Kenya, Sujata K. Bhatia • Plastics and Sustainability, Andrej Kržan • Polymers as Encapsulation Material in Agricultural Use, Dejan Štefanec • Characterization of Complex Macromolecules, Majda Žigon • Aging Characterization of Polymers, Gernot Oreski, Kenneth Möller and Gerald Pinter

chapter I.

Chapter I. POLICY IMPLICATIONS, SCIENCE AND TECHNOLOGY

KEY SUCCESS FACTORS OF CENTRES OF EXCELLENCE Gerd Meier zu Köcker Institute for Innovation and Technology mzk@iit-berlin.de

Introduction As a result of accelerated globalization and technology advances, competition has risen to new heights. Financial markets demand ever-faster growth. And growth – perhaps even survival – depends on innovation. The centrality of the individual opens new possibilities for micro consumers, micro producers and micro innovators and investors. In the globalised and digitalised world, all have the possibility to be connected and act, allowing individuals to participate more actively in society. Activeness and symbiotic relationships are occurring as informed customers are empowering the scene and forcing companies to react. Even the biggest companies do not possess the resources or the ability to act alone. Figure 1 and 2 compare how innovations happened in the past and how they happen today. In the past, Research and development were the main driver at the beginning. Inventing new technologies or products happened in laboratories or was done by researchers. These activities were completely disconnected by the market demands. Once a new idea was considered to be promising, additional developing activities were conducted to further develop the idea towards a prototype. In a next step, the prototype was further developed into a commercial product. Only once the product or technology was matured, the inventors started to think how to commercialise the product and technology. It was the time when the term “technology transfer” was created. Many technologies and products have been created by inventors and then had to be put in the markets. The majority of inventions never had been commercilised since the functional behavior was not according to the market demands or simply there was no market need. In the emerging new nature of innovation, a multitude of skills are required for solving complex challenges – which is why partnerships and collaborative network arise and symbiotic relationships are created between transnational companies, micro companies and public institutions. As shown in Figure 2, the main sources of innovations are nowadays partners, competitors and clients. Especially the latter ones are involved very early when a new product has been developed.

chapter I.

Phases of the innovation process

Results

Research

Invention

Development

Prototype

Production

Exploitable product

their competitive edge in the long run. CoEs are one answer to such needs. They have established as an important innovation driver worldwide in the past few years. The opening of the innovation process by means of an CoE helps enterprises considerably to innovate and get access to research facilities and other actors possessing know-how (that is, customers

Commercialisation

Mass application

Market success

too) has been named “Open Innovation”. Open

Impact on economy

potential of companies by obtaining external and

Figure 1: How innovation happened in the past [1]

Innovation is designed to enhance the innovation broadening internal know-how because it is based on cooperation with others. CoE are therefore responsible for sharing out know-how to the target persons, enabling them to learn from each other. The relevance of CoE for companies’ innovative capacity can be traced to the capacity of CoEs structures to encourage innovation.

Figure 2: Sources of innovations today [2] Figure 3: The innovation process, management by CoE [5]

Managing innovations provided by Centres oF Excellence Innovation management aims to provide, to implement and to apply methods and structures for cross company innovation activities and cooperation. This is done by formalising and systematising to a great extent process steps that constitute important milestones in such a development process [3] “Innovation management is the target-oriented planning, realisation and control of the innovation process leading business ideas to market success [4].”

Key success factors of Centre Excellence Nowadays, Centres of Excellence are a very popular tool to bring together industry and academia and enable more sustainable innovations. The rational is that such Centres, provided they are adequately staffed with researchers and are fully technologically equipped, can offer innovation related services according to their client’s needs. The clients are considered to be companies that need support in creating innovations. Thus they can offer R&D, if

A Centre of Excellence (CoE) can act as ideal

appropriate, but also support companies in how to

partner for companies to create innovations and to

better innovate new products and technologies.

increase their competitiveness. Unlike big companies, numerous small and medium enterprises do not have completely systematised / implemented processes of creating innovations due to their limited resources and personnel (inadequate control or shortened process chains, etc.). In contrast to that, CoE in some respects

However, although so many Centres of Excellence (CoE) exist all over the world, some of them are more successful than the others. What are the key success factors? In the following some key success factors are mentioned and further described.

reach the degree of complexity of larger companies. Innovative companies, and particularly small and medium-sized enterprises (SMEs), need reliable

Management of Centre

relations of cooperation with other partners from

The basis for success is a well functioning governance

the economic and research community to maintain

structure of the Centre, aimed at permitting smooth

chapter I.

processes inside the CoE and, at the same time, involving the main stake holders in the (strategic) decision making processes. The governance and

Innovation and Research Management

management of a CoE requires infrastructures and

Of course, the core task of CoEs is creating innovations

management procedures that differ substantially

and performing research. In CoEs a number of

from those in universities, research organizations

actors and institutions are involved, calling for the

and industry. However, these CoE structures and

management of innovation and research. Therefore,

procedures share numerous interfaces with the

innovation and research management issues play a

corresponding organisational environment and

key role both in the board/steering committee of a

requirements of these institutions.

CeO and in the management unit.

Therefore, when setting up a CoE, a very careful

• Board and administrative personnel should

design of the management and governance

be experienced in innovation and research

structures is desirable. However, in some cases,

management

relevant cornerstones are imposed by the funding programme or agency behind the CoE. Nevertheless, even then there is usually enough scope for individual design. Also, there are CoEs that are unrestricted in the choice of their management and governance structures. The following key questions have to be answered properly. • Board and/or Steering Committee •

should all partners have members on the board/steering committee? Which partners are necessary, which ones are “nice to have”? What is the ideal number of members appropriate to the decision-taking efficiency of the board/steering committee?

•

how much influence should be given to industry? Should it be in the majority - for example, in industry-led CoEs - or should it be balanced with the science and research influences?

•

should the funding agency have a seat on the board/steering committee?

•

• The CoE should have processes for strategic decision-making concerning innovation and research agendas, e.g., •

is an annual process for work planning needed?

•

how should partners be involved?

•

is a “demand-driven innovation and research agenda” desired? How can it be realized?

• Be familiar (and agree) with Intellectual Property issues, i.e., •

IP protection procedures

•

laboratory notebook practices

•

IP sub-board

•

publications protocol

• Continuously develop your research management skills, e.g., by •

State-of-the-Art Monitoring

•

Foresight review exercises

what are the responsibilities and duties of the board/steering committee and its members, and what do the corresponding decision structures look like?

• Status of the CoE

CoE administration • The day-to-day activities of CoEs, the networking among the partners and often the reporting and monitoring duties are taken over by an

•

should the CoE be a legal entity? What are the

administrative unit (CoE Management Office, CoE

pros and cons of having a distinct and separate

Administrative Office etc.).

legal entity? •

• When estimating/calculating the administrative

what should be the relationship to the host

effort, one has to take care not to underestimate

institution (if the CRC is not a stand-alone entity)

the resource required for the administration.

chapter I.

• To secure CoE success, it has to be ensured

in high risk research areas are also more likely to

that there is no discontinuity in management

require government support. Sustainability may

activities. Ideally, responsible administrative

then be a secondary issue, but a major sign of

personnel should have a professional background

success.

in both the thematic field of research and/or innovation management. Moreover, the structure

The lifespan of a funded CoE is, typically, 3 – 10

and personnel should be accepted by all network

years. If it is desired to “continue” the CoE, then

members.

consider innovative ways which would allow the CoE

• Administrators and project managers should be appointed and there should be ready access to accountants, PR specialists, legal & other specialists, as required • Ensure that there is an appropriate system for the

to accrue funds for use in its post-funding phase. One option would be, for example, to establish a foundation. However, beware of excessive focus on sustainability rather than on current quality.

collection of decentralised data as required to fulfil reporting duties • Be aware of rigorous legal and financial requirements • of EU State Aids • of Freedom of Information Acts

Conclusion A new nature of innovation is emerging. For all actors involved, science, industry and policy, it is important to understand how the nature of innovation is changing. Innovation is no longer mainly about science and technology. Firms can innovate in other ways. Co-

• of accounting requirements resulting from the financial guidelines of the funding scheme, e.g., the separation of costs & income from other funding streams

creation, user involvement, environmental and societal challenges increasingly drive innovation today. Collaborative, global networking and new public private partnerships are becoming crucial elements in companies’ innovation process.

Sustainability of CoEs

New nature of innovations also requests new tools to

Typically, CoEs are designed to contribute to increased

innovations. Centres of Excellence can contribute

competitiveness of the clients and the structure of

to facilitate the creation of new products and

regional/national research systems. Therefore, they

technologies in many sectors. Biopolymers are one of

should be self-sustaining. This means either that

them.

support industry and science in turning inventions into

1. they continue to exist after public funding has expired; or that 2. they produce outcomes that continue to exist after the cessation of public funding. Both of these aims have their own rationale and each

References 1.

FSU Jena, Fritsch, Innovationssysteme, 2009

Expanding the innovation horizont, IBM Global

will shape the way CoEs are structured and how they

CEO Study, 2006

function. Therefore CoE managements shall 3. • try to recognise at an early stage in the life of

Innovationsmanagement, München: Hanser

a CoE whether it is likely to “continue” (i.e., use

Verlag, 2009.

evaluations to probe for future plans), and avoid artificially prolonging their lifespan.

public outputs your CoE is producing, the more

Tintelnot, C. Innovationsmanagement, Berlin: Springer Verlag, 1999

• be realistic concerning sustainability: e.g., the more likely it will rely on public funding. CoEs that work

Müller-Prothmann, T., Dörr, N..

Bruns, Interorganisation innovation processes, dissertation, 2011

chapter II.

Chapter II. IDENTIFICATION OF NEEDS

Value-driven Engineering Stephen D. Fening and Frank L. Douglas Austen BioInnovation Institute in Akron fdouglas@abiakron.org

he culmination of a number of factors has moved the U.S. from the ‘Rising Storm’ to the ‘perfect storm’. The current economic crisis coupled with increased healthcare costs, global competition for talent, and increased

investment in innovation by emerging countries have the potential to erode U.S. global competitiveness. Specifically, the increasing commitment and ability of China, India, and Brazil to compete globally for talent, ideas, and infrastructure deployment in many areas of science and technology is evident in their increased investment in R&D. Within 10 years, China’s R&D investment as a percentage of GDP is expected to reach that of the U.S. [1]. The economic crises in the U.S. and Europe also present a relative competitive advantage to these three countries for global talent and ideas to create the next generation of technologies. Moreover, although 32 of 46 medical technology companies with $1 billion in revenue are presently based in the U.S. [2], many have simultaneously reduced U.S.-based R&D as they build up their presence abroad in response to increasing R&D investment, attractive corporate tax rates, competitive wage structures, and growing markets in these emerging countries. For example, in August 2011, General Electric (GE) moved its X-ray leadership team from the U.S. to China and has increased its R&D for products specific for the rural Chinese market in recent years [3]. In 2007, Stryker opened its Global Technology Center in Gurgao, India [4]. Furthermore, with U.S. health expenditures as a percentage of GDP projected to reach 19.3% by 2019 [5], innovation of new processes and products that further improve outcomes and reduce costs of health care is critical. This ‘perfect storm’ is increasing the call for a renewed focus on value. This focus on value is not new; various institutions have employed several definitions of value as a solution to an unmet problem (i.e., high costs). However, each has approached “value” differently. For example, the Department of Defense has used Value Engineering (VE) to improve their ability to obtain cost-effective services and products since 1954 [6]. As required by Public Law (PL) 104-106, which was signed by President Clinton in 1996, each executive agency in the U.S. Government must establish and maintain cost-effective VE procedures and processes [7]. In VE, value is defined as the ratio of function to life cycle cost. Similarly, the former Governor and Secretary of the U.S. Department of Health & Human Services,

chapter II.

Michael Leavitt, articulated the need for value in

these characteristics already exist. For example,

the healthcare industry as a means to drive down

OneBreath, Inc. has developed a low-cost ventilator

costs by simultaneously increasing competition and

that could be used in emerging markets as well as in

empowering the consumer [8]. In his speech, “Building

the event of a potential influenza pandemic. The first

a Value-based Health Care System”, Secy. Leavitt

OneBreath Ventilator is based on a novel platform

described value as a function of quality and cost.

technology, which represents a significant departure

More recently, in an approach to obtaining value in

from current designs, with the clinical need driving

healthcare delivery, Michael Porter defined value

specifications. It is less expensive to purchase (~$1000)

around the customer, focusing on health outcomes

and maintain, easier to use and more durable than

relative to the total costs associated with the full

existing ventilators while being as accurate. Other

cycle of care for a particular condition [9]. Because

examples include the Zio™ Patch, a long-term cardiac

maintaining good health is less costly than managing

rhythm monitor that provides continuous monitoring

poor health, Porter reasoned that a value-based

for up-to-14 days, GE’s VScan portable ultrasound,

system will contain healthcare costs [10].

as well as an inexpensive, point-of-care technology

None of the aforementioned approaches to value should be confused with frugal engineering, which focuses on understanding customer needs and delivering products and services to match those needs, in the most economical manner. Frugal engineering often entails the creation of devices or solutions that meet the needs of the end-user without the ‘bells and whistles’ or standard features. Examples of products developed using frugal engineering include Tata Motors’ Nano, a low-cost automobile, and Nokia’s 1100 cell phone. Historically, practitioners of frugal engineering reverse engineered existing products to identify the critical components needed to deliver the intended benefit and design solutions that contain primarily those critical components. The solutions are typically focused on a single market and often have limited applicability across other markets. The key components of the value-driven engineering include the following: clinical utility for the end-user, reduced complexity for the end-user, and reduced

that uses paper, as known as the “Lab-on-a-Chip” from Diagnostics for All [14]. Furthermore, elements of value-driven engineering (i.e., clinical utility, low cost, reduced complexity to the end-user) are evident in some of The Scientist’s annual Top 10 Innovations 2011, which includes LUCAS, an inexpensive, pocket-sized microscope, the PCR in a Pouch FilmArray system that simultaneously detects multiple pathogens in a shorter period of time without requiring a trained technician as well as the Mini MRI [15]. GE has several products which underscore the principles of value-driven engineering. For example, GE’s $1000 handheld electrocardiogram (ECG) machine, which was developed in an Indian R&D lab for use in rural India, improved clinical utility by enabling greater patient access, reduced cost to the healthcare system by improving compliance and lowing the cost of the device, and finally made the device less complex to operate than a typical ECG system. Another example from GE is the Vscan

costs to the healthcare system. Best quality of

portable ultrasound which offers similar benefits. While

materials, processes, and functionality as a sine qua

these devices were designed for markets like India,

non, as is patient-centricity. Reduced costs to the

because they address all three domains of value-

healthcare system is important because it implies that

driven engineering, they have broad market appeal

the device might actually cost more than predicate

and are now being sold in other markets, including

devices. Furthermore, decreased complexity to the

the United States. Furthermore, GE announced in May

end-user permits its use by downstream providers,

2009 that it will invest $3 billion to create 100 similar

dramatically reduces non-device costs, improves

healthcare innovations aimed at lowering costs,

patient compliance, and most importantly for target

increasing access, and improving quality [12].

markets – improves patient access.

A group of science leaders from academia, industry,

By simultaneously focusing on clinical utility, reduced

and government has been assembled to serve as

cost to system, and simplicity to end user, value-driven

a steering committee for the initiative. This group

engineering products have broad market reach and

released a White Paper, entitled “Value-driven

appeal to the patient, provider, and to the healthcare

Engineering and U.S. Global Competitiveness” on

system. Optimizing these elements throughout the

June 17, 2011 [13]. After receiving much attention, a

design, development and manufacturing phases

conference was held in Akron, OH in 2012 with over 300

remains a challenge. Fortunately, devices that fulfill

attendees from all over the Unites States. The initiative

chapter II.

is gaining ground internationally as well, serving as

a bedrock for a recent collaboration between the Austen BioInnovation Institute and Slovenia’s Center of Excellence in Polymer and Materials Technology.

china-ge-healthcare-idUSTRE76O3U520110725 4.

http://www.mpo-mag.com/news/2007/03/27/ stryker_opens_global_r%2526d_centre_for_

This partnership uses the principles of value-driven

medical_technology_in_gurgao

engineering to screen areas of innovation. Across the Austen BioInnovation Institute Partnership,

http://www.reuters.com/article/2011/07/25/us-

Centers for Medicare & Medicaid Services, Office

Value-Driven Engineering has become part of the

of the Actuary. National Health Expenditure

culture. It is a key competency throughout our

Projections 2009-2019 https://www.cms.gov/

entrepreneur education initiatives and is a key metric

NationalHealthExpendData/downloads/proj2009.

in screening technologies for commercialization. Most

pdf

of the products which have come out of the institute fully exhibit value-driven engineering: they improve

Systems Engineering. Value Engineering: A

clinical utility to the end user, reduce costs to the

Guidebook of Best Practices and Tools, 2011

healthcare system, and the use of these devices is less complex in use than their predicate.

Office of Deputy Assistant Secretary of Defense,

National Defense Authorization Act for Fiscal Year 1996, PUBLIC LAW 104–106—FEB. 10, 1996

Conclusions

Leavitt, MO Secretary, U.S. Department of Health and Human Services, Speech given on April 23,

Value-driven Engineering offers tremendous potential

2008 in Washington, DC, The Prologue Series

to serve as a tool to bring healthcare costs in line with

“Building a Value-based Health Care System.”

quality outcomes, something which is both needed in the US as well as critical to bolster our ability to remain globally competitive. It is an approach to developing new products that are in line with a set of core, defining value-driven Engineering principles: (1) clinical utility - driven by patient-centricity in demand, design, use and function, (2) reduced complexity - in

Porter, ME. What Is Value in Health Care? N Engl J Med 2010; 363:2477-2481

10. Porter, ME. A strategy for health care reform – toward a value-based system. N Engl J Med 2009; 361:109-112

the function of the device to the end user, and (3)

11. Sehgal V, Dehoff K, Panneer G. The importance of

cost savings and cost efficiency across the health

frugal engineering. strategy+business 2010; 59:1-5.

system. Cost is not the cost of a device, but rather the cost of the treatment of a disease. In value-driven Engineering, best quality of materials, processes, and functionality as sine qua non, as is patient-centricity.

12. http://www.ge.com/news/our_viewpoints/ healthcare_reform.html 13. http://www.abiakron.org/Data/Sites/1/pdf/ abiawhitepaper6-14-11.pdf

References: 1.

14. The One-Cent Solution: How a chemist and a doctor found a much cheaper way to diagnose

United Nations Educational, Scientific and Cultural

disease. Popsci http://www.popsci.com/

Organization and PWC

bown/2011/innovator

2010 Standard & Poor Industry Surveys: Healthcare – Products and Supplies

15. http://the-scientist.com/2012/01/01/top-teninnovations-2011/

chapter III.

Chapter III. BIOPOLYMER SCIENCE AND TECHNOLOGY

MEDICAL DEVICES AND BIOMATERIALS FOR KENYA Sujata K. Bhatia

Introduction

Harvard School of

A new class of implantable medical materials, constructed from naturally-derived

Engineering and Applied Sciences; Harvard Kennedy School of Government sbhatia@seas.harvard.edu

and renewably-sourced polymers, is poised to transform clinical medicine by providing materials with improved performance and versatility. Biopolymers can empower developing countries to leverage their own agricultural capabilities to contribute to novel medical technologies. Biochemical engineering and biomedical engineering, both of which fall under the broad category of biological engineering, are being brought to bear for the development of biobased materials as biomedical materials. Toward the goal of a sustainable bio-economy, research in biochemical engineering is increasingly devoted to the development of renewably sourced materials, such as bio-polymers and bio-composites derived from biomass and obtained from agricultural resources or microbial production. At the same time, innovators in biomedical engineering are seeking novel materials for implantable medical devices which will be optimally compatible with the human body. Such optimized materials will have properties of biocompatibility and mechanical tunability that maximize the clinical benefits of the implant. A natural intersect exists between these two areas of emerging research: naturally sourced polymers may be ideal for the design of new biomedical devices, as such polymers can effectively interface with human cells and tissues. This paper will discuss the evolving field of bio-based materials as biomedical implants, and describe success stories.

Defining Bio-Based Materials Bio-based materials, also known as biopolymers or bio-derived materials, are engineering materials made from substances which are derived in whole or in part from living matter.

chapter III.

Bio-based materials are classified into three main

construct and any degradation products must be

categories based on their origin and production [1]:

non-toxic and non-inflammatory. The implanted

• Bio-based materials can be directly extracted or removed from biomass. Examples of these biopolymers include polysaccharides such as starch, cellulose, alginates, carrageenan, pectin, dextran, chitin, and chitosan. Additional examples include proteins such as casein, glutein, whey, silk proteins, soy proteins, and corn proteins. • Bio-based materials can be produced via classical

material must not interfere with wound healing nor induce a foreign body response. New biomedical materials must be assessed throughout the development process, to ensure suitability for medical applications; characterization must include mechanical properties, physical and chemical properties, biological properties, shelf stability, and usability. The surgical target will determine the precise technical specifications for a given biomaterial.

chemical synthesis using bio-based monomers from

Clinician input is indispensable to the design process;

renewable agricultural resources. A prime example

surgeon needs and patient needs must guide the

is poly-lactic acid, a biopolyester that is made from

material design.

lactic acid monomers. The monomers themselves can be derived from fermentation of agricultural carbohydrate feedstocks, such as corn starch.

As the prevalence of chronic conditions such as cardiovascular disease, diabetes, arthritis, and neurodegenerative diseases rises in the global

• Bio-based materials can be produced directly

community, there will be an even greater need for

by microorganisms. The main example of a

innovative biomaterials that interact optimally with

biopolymer derived from microbial production

the human body. Bio-based polymers are increasingly

is the polyhydroxyalkanoate family of polymers.

being recognized as biocompatible materials

Additional examples include xanthan and

which can re-create natural, functional, bioactive

bacterial cellulose.

structures in the human body. Bio-based materials

Biopolymers are an intuitive choice for biomedical applications such as wound healing and tissue engineering, given that bio-based materials are constructed from naturally-derived materials, and may be expected to be friendly to biological tissues.

are characterized by both tissue compatibility and versatility, and have demonstrated success in wound closure, tissue repair, and tissue engineering. Such materials carry a great deal of hope for lightening the heavy burden of disease and death worldwide.

Moreover, bio-based materials possess tunable chemical, physical, and mechanical properties, so that these materials can be readily constructed to match the native properties of a variety of target tissues, and ultimately be implanted in the human body to enable re-growth of cells and tissues.

Success Stories: Carbohydrates for Closing Wounds One successful example of the utility of bio-derived materials for biomedical applications is that of

Requirements of Biomedical Materials

polysaccharide (carbohydrate)-based tissue glues.

A biomedical material may be defined as “a

Despite refinements in suturing and stapling

nonviable material used in a medical device,

techniques for wound closure, physicians continue

intended to interact with biological systems”

to struggle with the problem of leakage from internal

[2]. An essential characteristic of biomedical

wounds; a great demand exists for tissue adhesives

materials is biocompatibility, the ability to function

to augment or replace sutures and staples for internal

appropriately in the human body to produce the

wound repair. While tissue glues based on synthetic

desired clinical outcome, without causing adverse

chemicals such as cyanoacrylates or glutaraldehydes

effects. Biomedical materials must meet stringent

have been developed and commercialized, such

performance requirements: novel biomedical

adhesives have limited clinical usage, due to

materials must have sufficient physical, biological,

biocompatibility and performance problems including

and mechanical similarity to the natural physiological

inflammation and tissue damage. A family of hydrogel

environment. In addition, the biomedical material

tissue adhesives, based on the natural polysaccharide

There is a pressing need in clinical medicine for biomaterials that reliably close surgical wounds.

chapter III.

dextran, has thus been developed to overcome the

healing [8]. Tissue glues based on naturally-derived

limitations of existing tissue glues.

polysaccharides therefore represent a promising

Dextran is a high molecular-mass polysaccharide synthesized from sucrose, and composed of chains of D-glucose units [3]; the molecule was first discovered by Louis Pasteur as a microbial product in wine [4]. The polysaccharide is manufactured by lactic-acid bacteria, including Leuconostoc mesenteroides,

platform for sealing and healing soft tissues. The polysaccharide-based materials will find clinical utility in general surgery, cardiothoracic surgery, vascular surgery, emergency medicine, trauma surgery, and ophthalmology, just to name a few of the numerous medical applications.

Streptococcus mutans, and Lactobacillus brevis, as well as Aerobacter capsulatum. Dextran already expander, for the treatment of circulatory shock.

Success Stories: Soy for Securing Bone

Dextran-based tissue glues have been created

Bio-based materials have demonstrated potential

by reacting dextran aldehyde with multi-arm

not only for wound closure in soft tissues, but also

polyethylene glycol-amines; the two components form

for repair of bony defects. Damages and defects

a crosslinked hydrogel [5]. This system crosslinks on wet

in bone can result from traumatic events or surgical

tissues, cures rapidly in less than one minute at room

procedures; when the defect reaches a critical size,

temperature, adheres to moist tissue, and degrades

the bone is unable to spontaneously regenerate,

hydrolytically. The polysaccharide-based tissue

and bone fillers are required to support new bone

adhesive is also advantageous in that it is free of blood

formation. Bone reconstruction requires materials

products, so there is no potential for viral transmission.

that are easy to handle, biodegradable, non-

In vitro testing of the dextran-based tissue glues

cytotoxic, non-immunogenic, and capable of

with clinically relevant cell lines reveals that these

inducing bony regeneration. Currently there are

adhesives are non-cytotoxic to connective tissue

no commercial bone fillers that meet all of these

fibroblasts, and do not elicit release of inflammatory

technical requirements. Soybeans can be a source of

mediators (in contrast, commercial tissue adhesives

naturally bioactive implantable materials; soybeans

based on cyanoacrylate are highly cytotoxic to

contain bioactive phytoestrogens that can induce

connective tissue fibroblasts). The biocompatibility,

differentiation of osteoblasts (bone-forming cells). An

biodegradability, adhesion properties, and

innovative class of bioactive fillers based on soybeans

convenience of polysaccharide-based tissue glues

has thus been created for bony reconstruction.

has a long history of clinical use as a plasma volume

make these adhesives an effective system for treating a wide variety of wounds. The foundation chemistry enables fine-tuning of sealant properties, including cure rate, degradation rate, and swelling, to meet

Soybean-based biomaterials are synthesized by simple thermosetting of defatted soybean flour; the soybean-based biomaterial is ductile and can be

surgeon needs for specific clinical targets.

processed into films, membranes, porous scaffolds,

In preclinical studies, dextran-based tissue adhesives

Alternatively, soybean-based formulations can be

have demonstrated success in closing a variety of

obtained by extraction of a fraction enriched in the

surgical incisions and wounds, including vascular graft

main soy components, resulting in a soft hydrogel. The

closures; aortic graft closures; aortic punctures; aortic

ductility of soybean-based biomaterials enables these

anastomosis; graft punctures; cardiac punctures;

fillers to be readily adapted to the site of implantation.

coronary artery incisions; intestinal anastomosis;

The biomaterials absorb water, with the swollen

hernia patch attachment; liver lobectomy; and

material assuming a rubbery consistency, and the

splenectomy [6]. The sealant is well-tolerated in short-

materials degrade in a controlled fashion. Soybean-

term and long-term studies; the sealant remains on

based biomaterial granules have been shown to

the target site with no injury to adjacent tissues. In

be bioactive in vitro; the soybean-based granules

addition, the polysaccharide-based tissue adhesive is

reduce the activity of inflammatory monocytes and

successful in sealing corneal incisions, and is non-toxic

macrophages; reduce the activity of osteoclasts

to corneal cells [7]. The tissue adhesive is strongly

(bone-removing cells); and increase the activity of

bonding and sufficiently robust that 1-2 microliters of

osteoblasts (bone-forming cells). These results suggest

the dextran-based tissue glue is capable of sealing

that upon implantation, the soybean-based bone

a clear corneal incision through the first five days of

filler may be able to reduce chronic inflammation

and granules for various surgical applications [9].

chapter III.

while simultaneously promoting bone regeneration by

are characterized by a unique combination of high

stimulating bone cells. The soybean-based materials

strength and extensibility [14]. The toughness of silk

additionally induce calcification of bone noduli.

fibers is superior to that of any commercially available,

Importantly, the soybean-based bone filler is cost-

synthetic high-performance fiber. Silk fibers have

effective to produce, relative to commercial bone

been in clinical use as sutures for centuries [15]; fibers

fillers [10]. Unlike existing bone fillers which are loaded

composed of the silk fibroin protein are biocompatible,

with expensive growth factors, soybean-based bone

and slowly degrade over several weeks in vivo. Silk

fillers do not require the addition of exogenous growth

fibers are therefore long-term degradable biomaterials

factors for bioactivity.

with excellent mechanical properties. The fibers can

Soybean-based bone fillers have been evaluated in pre-clinical rabbit models of bony defect repair, and the fillers have shown efficacy in inducing bone

slowly and predictably transfer a load-bearing burden to nascent biological tissues [16], making silk an ideal platform for tissue engineering.

formation in vivo over 8 weeks of implantation [11].

Silk hydrogels have been prepared from aqueous

Treatment with soybean-based granules produces

solutions of silk protein via sonication-induced gelation

bone repair and healing, with progressively maturing

[17]. One particular silk hydrogel has been formulated

structural features of bone, as well as cellular features

to yield mechanical properties similar to those of

superior to those obtained from healing in a non-

cartilage; these scaffolds can support the proliferation

treated bony defect. Moreover, in a rabbit model of

of chondrocytes, and may be utilized for cartilage

defects of cancellous bone (the spongy inner layer

tissue engineering [18]. Silk nanofibers can also be

of bone that protects bone marrow), treatment with

manufactured by aqueous-based electrospinning

soybean-based fillers resulted in significantly higher

of silk and silk/poly(ethylene oxide) blends [19].

outer bone formation and microhardness at 24 weeks

Electrospun silk protein scaffolds have been evaluated

than did treatment with a commercial synthetic

for vascular tissue engineering, and can support the

bone filler [12]. Soybean-based bone fillers may be

growth of human aortic endothelial cells and human

suitable for orthopedic, maxillofacial, and periodontal

coronary artery smooth muscle cells. Moreover,

surgeries.

electrospun silk scaffolds stimulate the formation

Further, soybean-based biomaterials have been combined with gelatin and hydroxyapatite composites to create injectable foamed bone cements [13]. The soy/gelatin/hydroxyapatite foam contains interconnected pores after injection; this porosity allows the infiltration of osteoblast cells into the scaffold. The composite foam favors osteoblast adhesion and growth; some cells establish a very close contact with the material surface. Because soy-based bone cements are injectable, these cements could be utilized for bone regeneration in a minimally invasive fashion. Clinical applications for these novel foamed cements include vertebroplasty and kyphoplasty for the treatment of vertebral fractures, and implant fixation procedures.

of interconnecting networks of capillary tubes [20]. Electrospun silk nanofibers can be shaped into tubular materials with sufficient mechanical strength to withstand physiological blood pressures, and may find utility as tissue-engineered vascular grafts. Silk scaffolds have additionally demonstrated potential for bone tissue engineering and ligament tissue engineering. Towards bone tissue engineering, silk scaffolds have been chemically modified with covalently bound RGD peptide sequences. These scaffolds promote the attachment of human bone marrow-derived mesenchymal stem cells, and demonstrate mineralization and the formation of organized bonelike trabeculae [21]. For ligament tissue engineering, silk-fiber matrices have been designed to match the mechanical requirements of

Success Stories: Silk for Scaffolding Tissues

a native human anterior cruciate ligament, including fatigue performance. These matrices support attachment, expansion, and differentiation of adult human progenitor bone marrow stem cells [22]. Silk-

Just as polysaccharide-based glues may transform soft

based biomaterials have even demonstrated the

tissue closure, and soybean-based fillers may advance

ability to support neurite outgrowth from dorsal root

bone repair, silk-based biomaterials have the potential

ganglia neurons, and silk conduits are capable of

to enhance tissue engineering. Silk protein fibers

bridging short gaps in severed nerves by enabling

are produced by both silkworms and spiders, and

axonal regeneration [23]. Further, in a rat model

chapter III.

of peripheral nerve injury, silk conduit implantation

from these crop products seems to be a viable

allows nerve repair and functional recovery. Given

option worth investigation. Bio-based polymers can

the outstanding mechanical properties and aqueous

empower developing countries to leverage their

processability of silk fibers, as well as the ability of silk

own agricultural capabilities to enter the biomedical

scaffolds to support numerous cellular populations

revolution. Biopolymer scientists can therefore

including stem cells, silk-based biomaterials may

consider themselves as not only part of the research

eventually find applications for tissue engineering in

and development team, but also as part of the patient

every organ system of the body.

care team.

Future Directions

Literature Cited

Bio-based materials, derived from natural polymers

Weber, C.J., Biobased Packaging Materials for the

including polysaccharides and proteins, are

Food Industry: Status and Perspectives. European

poised to transform clinical medicine by supplying

Union Directorate 12: Royal Veterinary and

biomedical materials with improved properties of

Agricultural University, Frederiksberg, Denmark

biocompatibility, ease of handling, and mechanical

(2000).

strength. The success stories of polysaccharidebased tissue glues for wound closure; soybean-

Ratner, B.D., et al., Biomaterials Science: An

based biomaterials for bone reconstruction;

Introduction to Materials in Medicine. Academic

and silk-based scaffolds for tissue engineering all

Press: New York (1996).

illustrate the versatility and capability of bio-based materials as biological materials. Even more types

and characteristics of mutants of Leuconostoc

of naturally-derived materials are on the horizon for

mesenteroides B-742 constitutive for dextran,”

clinical medicine. New polymers, synthesized using

Enzyme and Microbial Technology, 17, pp. 689-695

monomers obtained from agricultural resources,

(August 1995).

are one avenue for future innovation. For instance, films and plastics composed of corn-derived

Kim, D., and J.F. Robyt, “Production, selection,

4. Pasteur, L., “On the viscous fermentation and the

1,3-propanediol have been demonstrated to be non-

butyrous fermentation,” Bulletin de la Société

cytotoxic and non-inflammatory to clinically relevant

Chimique de Paris, 11, pp. 30-31 (1861).

cell lines [24]; such materials may be readily adapted for biomedical implants. Agricultural resources such

5. Bhatia, S.K., et al.,“Interactions of polysaccharide-

as soy, kenaf, flax, and cellulose may also provide

based tissue adhesives with clinically relevant

useful starting materials for implantable medical

macrophage and fibroblast cell lines,”

devices. Moreover, additional polymers derived

Biotechnology Letters, 29, pp. 1645-1649 (Nov.

from microbial production are under exploration. As

2007).

an example, polyhydroxyalkanoates are naturallyoccurring polyesters that are synthesized by most

6. Bhatia, S.K., et al., “Polysaccharide-based tissue adhesives for closure of surgical wounds,”

bacteria, and these materials are being investigated

Proceedings of the 2008 American Institute

for tissue engineering [25] and targeted drug delivery

of Chemical Engineers Annual Meeting,

[26]. With progressive efforts of biopolymer scientists

Philadelphia, PA (Nov. 16-20, 2008).

in these areas, physicians and surgeons will soon see novel biopolymers for clinical applications.

adhesives for sealing corneal incisions,” Current

Moreover, naturally-derived polymers can allow

Eye Research, 32, pp. 1045-1050 (Dec. 2007).

developing nations to join in the biomedical revolution in ways that were not previously possible [27]. Agriculture tends to play a significant role in the

8. Chenault, H.K., et al., “Sealing and healing of clear corneal incisions with an improved dextran

economies of developing nations, particularly those

aldehyde-PEG amine tissue adhesive,” Current

in tropical or semi-tropical regions. Taking the relative

Eye Research, 36, pp. 997-1004 (Nov. 2011).

strengths of these economies, and in particular the strengths of individuals at the community level, a new “technology” that makes use of materials derived

Bhatia, S.K., et al., “Polysaccharide-based tissue

Santin, M., et al., “A new class of bioactive and biodegradable soybean-based bone fillers,”

chapter III.

Biomacromolecules, 8, pp. 2706-2711 (Sep. 2007). 10. Santin, M., and L. Ambrosio, “Soybean-based biomaterials: preparation, properties and tissue regeneration potential,” Expert Reviews in Medical Devices, 5, pp. 349-358 (May 2008). 11. Merolli, A., et al., “A degradable soybean-based biomaterial used effectively as a bone filler in vivo

19. Jin, H.-J., et al., “Electrospinning Bombyx mori silk with poly(ethylene oxide),” Biomacromolecules, 3, pp. 1233-1239 (August 2002). 20. Zhang, X., et al., “In vitro evaluation of electrospun silk fibroin scaffolds for vascular cell growth,” Biomaterials, 29, pp. 2217-2227 (May 2008). 21. Meinel, L., et al., “Engineering bone-like tissue in

in a rabbit,” Biomedical Materials, 5, pp. 15008

vitro using human bone marrow stem cells and

(Feb. 2010).

silk scaffolds,” Journal of Biomedical Materials

12. Giavaresi, G., et al., “Bone regeneration potential of a soybean-based filler: experimental study in a rabbit cancellous bone defects,” Journal of Materials Science: Materials in Medicine, 21, pp. 615-626 (Feb. 2010). 13. Perut, F., et al., “Novel soybean/gelatine-based bioactive and injectable hydroxyapatite foam: material properties and cell response,” Acta Biomaterialia, 7, pp. 1780-1787 (April 2011). 14. Omenetto, F.G., and D.L. Kaplan, “New opportunities for an ancient material,” Science, 329, pp. 528-531 (July 30, 2010). 15. Moy, R.L., et al., “Commonly used suture materials in skin surgery,” American Family Physician, 44, pp. 2123-2128 (Dec. 1991). 16. Horan, R.L., et al., “In vitro degradation of silk fibroin,” Biomaterials, 26, pp. 3385-3393 (June 2005). 17. Wang, X., et al., “Sonication-induced gelation of silk fibroin for cell encapsulation,” Biomaterials, 29, pp. 1054-1064 (March 2008). 18. Chao, P.-H.G., et al., “Silk hydrogel for cartilage

Research A, 71, pp. 25-34 (October 2004). 22. Altman, G.H., et al., “Silk matrix for tissue engineered anterior cruciate ligaments,” Biomaterials, 23, pp. 4131-4141 (October 2002). 23. Huang, W., et al., “Regenerative potential of silk conduits in repair of peripheral nerve injury in adult rats,” Biomaterials, 33, pp. 59-71 (January 2012). 24. Bhatia, S.K., and J.V. Kurian, “Biological characterization of Sorona polymer from cornderived 1,3-propanediol,” Biotechnology Letters, 30, pp. 619-623 (April 2008). 25. Hoefer, P., “Activation of polyhydroxyalkanoates: functionalization and modification,” Frontiers in Bioscience, 15, p. 93-121 (January 2010). 26. Grage, K., et al., “Bacterial polyhydroxyalkanoate granules: biogenesis, structure, and potential use as nano-/micro-beads in biotechnological and biomedical applications,” Biomacromolecules, 10, pp. 660-669 (April 2009). 27. Fatunde, O.A., and S.K. Bhatia, “Health care in the developing world: embracing a new definition

tissue engineering,” Journal of Biomedical

of medical technology to include biomaterials,”

Materials Research B: Applied Biomaterials, 95,

Ethics in Biology, Engineering, and Medicine, 2,

pp. 84-90 (October 2010).

pp. 353-364 (2011).

chapter III.

PLASTICS AND SUSTAINABILITY Andrej Kr탑an Center of Excellence PoliMaT andrej.krzan@ki.si

Introduction To many critical observers the mere mention of plastics and sustainability in a common context is a contradiction in terms. But the truth is that we use plastics in ways that are more or less sustainable. Although not perfect from the sustainability point of view, modern technologies and approaches associated with plastics use, production and waste management are making plastics more sustainable that they ever were. In fact, these unique man-made artificial materials may find a way to coexist and even connect with nature in unexpected ways. Polymers and plastics are an extremely broad and versatile group of materials. Although they were discovered only in the second half of the 19 th century, their global production is now nearing 300 million tons. This, as well as the fact that we find plastics all around us, shows the great popularity of these materials. Plastics offer an excellent cost-to-performance ratio that can hardly be matched by other materials. The life of everyone today is impacted by plastics: through sterile, single use devices that help provide fast and safe medical treatment, plastic packaging that ensures safe food and prevents spoilage of food, safety devices such as airbags that save human lives, heat insulation using plastics that saves energy, plastics that are necessary for IT equipment which has brought about great efficiency improvements, and, not least, plastics have also conquered areas such as sports equipment or toys. Plastics are behind all important improvements in renewable energy: they make large wind turbines possible, they are an integral part of new flexible solar cells, they provide for energy savings in LED lighting, lower vehicle fuel consumption through reduced weight, etc. The sustainability of plastics has been seriously improved by the optimization of plastics production that has taken place, particularly in the 20 th century. This large-scale industry enjoys the benefits of productions of scale and is less resource demanding than the production of traditional materials such as metals, glass and paper. More recently, improvements in the recycling of plastics, particularly through improved waste management in many parts of the world, have opened the way to substantial resource savings. Recycling is now considered to be the most efficient method for plastic waste management, easily outperforming energyto-waste options. Studies have shown that recycling can reduce the need for resources by more than 50 %. In general, improvements of such magnitude are very difficult or close to impossible to implement in the production and processing of plastics. Although the useful life of plastics is almost exclusively a tale of efficiency and market success, the life of plastics still has two weak points. The first is linked to its production: plastics are based almost exclusively on non-renewable fossil resources. This is important since the fossil resources used for the production of plastics is being used at a rate that is degrees of magnitude higher than the rates at which it could (even theoretically) be replenished. A practical consequence of our actions is that we are very rapidly transferring fossilized carbon into the

chapter III.

environment, primarily into the atmosphere where it

or glycols at elevated temperatures. TPS is normally

contributes to climate-altering processes. The second

blended with biodegradable polyesters to improve

weak point sets in after we discard plastics: if they find

its material properties and processing properties. TPS

their way into nature they are quite durable and are

is mainly used for film blowing and is commonly used

able to harm the environment in a number of ways.

for packaging, as well as for bags for organic waste collection.

Bioplastics Both of the above shortcomings may be addressed by bioplastics. According to the leading industry

TPS preparation starts with a natural polymer whose polymer structure is preserved during physicochemical processing. The most commonly used sources of starch are corn/maize, potatoes, and cassava.

association in the field (European Bioplastics), bioplastics are biobased and/or biodegradable plastics. Bioplastics offer a novel route to raising the sustainability of plastics to a new level. The use of biobased plastics addresses the issue of fossil resources as the primary resource base for plastics production. Through the use of biobased â&#x20AC;&#x201C; renewable sources the kinetics of material cycles can be synchronized with the natural cycles, thus avoiding the imbalance we are currently fuelling through the use of fossil resources. Biodegradable plastics offer a solution to the problems caused by plastics in nature. Although biodegradable plastics should never be seen as a technological remedy that will legitimize littering, they do open a route to reentering plastics into natural material cycles. Ideally, the combination of both the biobased and biodegradable character could lead to a man-made material that, like products of nature, arises from natural renewable sources and reverts back to them after being discarded. This indeed is a remarkable feat for unnatural materials such as plastics.

Polylactide (a.k.a. Polylactic acid, PLA) PLA is chemically synthesized from a natural compound, lactic acid, obtained through fermentation of sugars that are commonly prepared from starch. Lactic acid is first oligomerized and then transformed into a cyclic dimer of lactic acid, lactide, which is then polymerized through a ring opening polymerization process. The obtained PLA is a high quality material. Its thermal properties depend on the chirality of the lactic acid moieties. Common PLA grades are not suitable for use above its relatively low (approx. 60 oC) glass transition temperature. The polymer biodegrades under industrial composting conditions but remains stable under home composting conditions. PLA is based on a fermentation of sugars to produce lactic acid â&#x20AC;&#x201C; the monomer that is then converted to PLA in a number of chemical steps. The production depends on using a natural compound as a monomer, although the polymer itself is not a natural form.

Examples of bioplastics

Polyhydroxyalkanoates (PHA)

There are a number of bioplastics that are currently

PHAs are a diverse group of fully natural thermoplastic

commercially available. It is particularly interesting to look at the principles through which they area made since they depend on different raw materials and various combinations of physicochemical and biological processing. The selected examples presented below serve to illustrate these approaches.

polyesters produced by native microorganisms as a material and energy storage. PHA are composed from B-hydroxyacids so a number of polymers can be prepared. The most common are poly-3hydroxybutyrate (PHB), poly-4-hydroxybutyrate, and poly-3-hydroxy butyrate-co-3- hydroxy valerate (PHBV). Production is based on the fermentation of

Thermoplastic starch (TPS) A natural carbohydrate polymer - starch is used as material and energy storage in many plants. In nature, starch is made of a mixture of amylose and

sugars or other substrates directly to the polyester. PHA is formed into granules inside the microorganism. At the optimal time, the fermentation is stopped and the polyester is extracted from the biomass.

amylopectin in crystalline granular form, these can

A recent trend in the plastics industry is to produce

then be turned into a procesable thermoplastic

exact equivalents of non-biobased conventional

mass through mixing with plasticizers such as water

plastics from new biobased sources. This approach

cHAPteR III.

is based on new production methods for basic

Isosorbide:

chemicals and monomers from biomass, which can be used in conventional polymer and plastic production. two notable examples of this approach are bio-polyethylene (bioPe) and biopolyethyleneterephtahalate (bioPet), although many others are becoming available. these bioplastics that are entering into an already developed market are expected to experience very fast growth over the next few years. Bio polyethylene (bioPE)

BIOMaSS SOurCeS A key question related to bioplastics, and particularly

BioPe production is based on ethanol production

biobased plastics, is the type and source of biomass

through fermentation of sugars. ethanol is

used in their production. currently, the raw materials

then dehydrated to ethylene, which enters the

used are almost exclusively starch, sugars and oils.

conventional polymerization process to produce

All of these can also be used for food and feed

polyethylene. the product is technically equal to Pe

production, which opens ethical issues and food

produced from fossil resources. the process will likely

supply questions. At the current production levels, the

be improved by the use of new second-generation

demand for raw materials for plastics production is

sources such as cellulose. However, the fermentation

not critical, however as the production of bioplastics

from sugar to ethanol is a relatively wasteful step

is expected to grow at rates close 15 % annually this

in terms of carbon utilization. BioPe is commercially

may soon become an issue.

available. Bio polyethyleneterephthalate (bioPET) currently, commercial bioPet uses biobased ethylene glycol in the polymerization of Pet to produce 30 % biobased carbon Pet. the production of biobased terephathalic acid ,the other co-monomer used in Pet synthesis, is currently in a late development stage and will become available shortly. After this is implemented, fully 100 % biobased bioPet will

this prospect leads to the need to develop socalled second generation renewable resources. these are less convenient to use and include lignocellulosic resources such as wood, waste streams from agricultural and food production, as well as other waste biomass. With the change in biomass importance it is also expected that production will, at least in part, move to locations where abundant biomass can be produced.

become available. the production of bio terephthalic

so, in addition to a technological change, a

acid is based on new processes for the production

geographic shift can be expected as well. In the

of BtX (benzene, toluene, xylene) aromatics from

current analyses, south-east Asia, and north and

bioresources. P-Xylene is then easily transformed in

south America fi gure as important biomass sources.

terephthalic acid. the advent of biobased aromatics

Interestingly, Africa, despite its wealth of biomass

will allow these products to enter into many other

potential, is largely absent from such analyses. this is,

polymer production streams, such as PU, Ps, PA, etc.,

in part, attributed to limitations in transportation and

thus providing the biobased polymer portfolio with a

the overall lower organizational and technological

new expansion route.

level of Africa. the potential of Africa as an important biomass source can, however, be estimated from

Isosorbide based polymers In addition to making known plastics biobased, a

the fact that Africa produces the same crops cited as having the highest potential biomass and the potential to intensify their production.

number of new biobased polymers are also being introduced into the market. An example illustrating this trend is the isosorbide monomer developed by Roquette. Isosorbide is produced from starch and

BIOreFINerIeS

glucose. the cyclic monomer with two hydroxyl groups

An important development in the use of biomass is in

is suitable to be incorporated into polyesters to form a

the deeper integration of the production of energy,

Pet analogue material (PeIt) or into polycarbonates.

chemicals, and materials. the guiding principle is

chapter III.

to use all components of biomass and to extract the highest possible value. This differs from past practices where a certain valuable component was extracted and the rest was discarded, often causing a

Sources and further reading 1.

bioplastics.org

substantial environmental burden. Integrated biomass utilization will take place in complex processing facilities, i.e. biorefineries that mimic in their setup the

and construction stage although some are already

aspx?DocId=7314

more to enter operation, resulting in the growth of 4.

using fossil resources.

Joint European Biorefinery vision for 2030, StarCOLIBRI

the market. With time, biorefineries are expected to grow into proper alternatives to conventional refineries

Bio-based Chemicals, Value added Products from Biorefineries www.ieabioenergy.com/DownLoad.

in operation. In the immediate future we can expect the renewable chemicals and materials available on

Biobased plastics: www.bioplastic-innovation. com

multi-stage and complete utilization of fossil resources. Currently, biorefineries are mainly in the planning

European Bioplastics: www.en.european-

www.star-colibri.eu/files/files/vision-web.pdf

Plastic Waste in the Environment- report provided by the European Commission DG ENV: http://

Conclusions Plastics are a mature material class that is undergoing a significant evolutionary step leading to higher

www.plastice.org/links/plastic-waste-in-theenvironment/ 7.

Degradable Plastics

sustainability. The superb understanding of the polymeric nature of plastics that has lead to their great utility is now increasingly combined with nature

www.biodeg.net/fichiers/Training%20course%20 (Eng).pdf

mimicking approaches that connect plastics to nature through the use of renewable raw materials

Leonardo da Vinci Program - Environmentally

Tutorial on Biodegradable plastics: Principles of

and structures that can seamlessly return to nature

biodegradable plastics, the science, the hype

after they are no longer needed.

and the misleading claims

The intensification of biomass use still poses a number

10. http://www.assobioplastica.org/wp-content/

of questions that will lead to the emergence of a new

uploads/2011/04/Principles-of-BIODEGRADABLE-

integrated production of energy, chemicals, and

PLASTICS-the-science-the-hype-and-the-

materials in the form of biorefineries.

misleading-claims.pdf

chapter III.

POLYMERS AS ENCAPSULATION MATERIAL IN AGRICULTURAL USE Dejan Štefanec Center of Excellence PoliMaT; MikroCaps Ltd.

Introduction Most commercial substances used for agriculture dissolve or evaporate rapidly in the environment and therefore contaminate in a large scale. Fertilizers dissolve at

dejan.stefanec@

a higher rate than is needed by plants. Excess fertilizers leach into the groundwater

mikrocaps.com

and gases evolve into the atmosphere. Highly volatile pesticides evaporate into the air or are washed into the soil. Handling of toxic compounds is becoming more and more important. To avoid these problems, coating and encapsulation technologies may be used. Substances are encapsulated by a special polymer membrane which release active chemicals into the environment in small dosages have many advantages. Encapsulated products are applied only once at the beginning of the growing season and provide gradual release throughout the whole season. Therefore the consumption of the active compounds is more efficient.

(Micro)encapsulation Encapsulation is a process in which solid particles or liquid droplets are surrounded by a polymeric membrane in order to change their physical properties without influence to chemistry nature. The resultant product of such a process are (micro)capsules, which may be permeable, semi-permeable or impermeable. Compatibility of the core material with the membrane is an important criterion for enhancing the efficiency of encapsulation. The development of microencapsulation began with the preparation of capsules containing dyes for incorporation into paper for copying purposes. In the past 10 years this approach has been explored widely in pharmaceutical industry, agricultural, food, cosmetic and textile industries. Depending on the applications, a wide range of core material could be encapsulated, including pigments, dyes, monomers, catalysts, pesticides, fragrances (Ghosh, 2006). Microcapsules have a number of advantages and the main reasons for encapsulation can be summarised as follows: • Controlled, sustained or timed released. • Protection of unstable materials. • Better processability (improving solubility, dispersibility, flowability). • Safe and convenient handling of toxic materials. • Masking of odour or taste. • Handling liquid as solids.

cHAPteR III.

numerous preparation technologies for the encapsulation of the core material have been reported. the most important processes are: • Physico-mechanical techniques: spray drying, fluid bed coating, centrifugal techniques, vacuum encapsulation, electrostatic encapsulation; • Physico-chemical techniques: coacervation, sol-gel encapsulation, supercritical co2 encapsulation; • chemical processes: suspension, dispersion and emulsion polymerisation, polycondensation. the type of encapsulation technology and membrane is dependent mainly from the properties of the core material, application type and desired releasing method. For microencapsulation of liquid substances such a pesticides usually chemical methods are used but for coating of solid particles like fertilizers mechanical methods are more often used.

• substances are protected against environmental degradation, • Reduction of leaching into the environment, • Decreased costs as less active material is needed, • safe handling. capsule suspension formulations are water based dispersions of capsules where a liquid pesticide is caught in an inert shell. Microencapsulation of pesticides is usually done by interfacial polymerisation or phase separation. the only technique suitable for biological pesticides is phase separation. Interfacial polymerisation (Figure 1) is the method of choice for encapsulation of highly toxic insecticides, as the active ingredient is completely enveloped by the polymer. In the first stage, an emulsion of pesticides in water is prepared and after that a reaction is occurred. Because of monomers presence in both phases, internal and

MICrOeNCaPSuLaTeD PeSTICIDeS Pesticides are conventionally applied to crops by

continuous, interfacial polymerisation will take a place only on the surface of pesticides droplets. the resulting aqueous dispersion of microcapsules may be dried to get a dry powder capsules with pesticides content.

periodic broadcasting or spraying. Very high, and

After applying of formulation water evaporates

possibly toxic, concentrations are applied initially,

and only capsules rest on the spraying surface. the

and these often decrease rapidly in the field of

pesticide slowly pass on the surface of capsules

concentration that fall below the minimum effective

that are all the time activated (Hirech, 2003; Behles,

level. As a result, repeated applications are needed to

2007). the membrane may be slow released (release

maintain pest control (Benita 2006).

takes place by diffusion), or fast released (thin wall

Due to some research results up to 98 % of sprayed insecticides and 95 % of herbicides reach a destination other than their target species, including air, water,

membranes allow relatively fast release of the total contents of the microcapsules after small mechanical stress).

sediments and food (Miller, 2004). Because of new ecological legislations and increased awareness of users, new formulations of pesticides are more

Active Substance

and more important. those are sc (suspension concentrate), WG (Water dispersible Granules) and cs formulations (capsule suspensions).

Emulsion

Reaction

Microcapsules with active substance

especially cs formulations have a many advantages like (Benita 2006):

Figure 1: Microencapsulation by interfacial polymerisation.

• controlled release of active ingredients, • could be used for inner and outdoor applications,

COaTeD FerTILIZerS

• suits to new legislation,

Beside pesticides one of the major pollutants in

• Are suitable also for non professionals, • Lower phytotoxicity,

the agriculture are fertilizers. Because of fast water dissolving and nutrients leaching fertilizer efficiency is very short. In the case of major rain fall leaching

cHAPteR III.

into the soil and groundwater is increasing up to 75%

encapsulation (or coating) of solid particles like

of nutrients content therefore fertilisation should be

fertilizers could be done using sulphur or polymeric

repeated several times per year in order to ensure

materials, therefore there are three main groups of

constant nutrient availability (shaviv, 2000).

encapsulated fertilizers are sulphur coated, polymer

nutrient leaching could be decreased by using coated fertilizers. those are fertilizers protected with a special membrane (Figure 2), which gives them many advantages over traditional fertilizers. the membrane enables the safe handling of fertilizers and prevents them from dissolving and losing nutrients too fast. nutrient utilisation is thus more efficient, the

sulphur coated and polymer coated fertilizers. Polymer membrane is mainly prepared by polymers (e.g. polyvinylidenchlorid (PVDc)-based copolymers, gelforming polymers, polyolefine, polyethylene, ethylenevinyl-acetate, polyesters, urea formaldehyde resin, alkyd-type resins, polyurethane-like resins,etc.), fatty acid salts (e.g. calcium-stereate), latex, rubber, guar gum, petroleum derived anti-caking agents and wax

active operating time is longer and fewer nutrients are

(trenkel, 2010). coating procedure in a fluid bed coater

washed into ground water. Major advantages of using

with polymer membrane in shown in the Figure 3.

coated fertilizers are: • Applying once in a season, • safe fertilization, with no burns,

Fertilizers

• Better utilization of nutrients, • Rich and strong growth throughout the season, • Lower level of nutrients washing into ground water,

Coating solution Coated fertilizers

• Lower quantity of fertilizers used and • saving of time.

Figure 3: Fertilizer coating in ﬂuid bed coater.

MICrOeNCaPSuLaTeD eSSeNTIaL OILS aS GreeN PeSTICIDeS Due to increasingly strict environmental regulations and peoples environment aware is a great tendency for the development and use of natural pesticides. Use Figure 2: Scanning electron microscope image of MikroCaps coated fertilizer.

of natural pesticides such a pyrethroids and bacterial larvacides are well known however many usages of essential oil emerge as “green pesticides” (Koul,

nutrient release takes place according to the principle of diffusion and osmosis through a semi-permeable membrane. Moisture in the ground penetrates into the fertilizer and dissolves the nutrients, which are released into the ground in a controlled way where plants use

2008). synthetic substances appeared to be a perfect solution in the fight against insects and other pests, but nowadays the negative impact on the environment have become obvious therefore many organisations are seeking to return to green pesticides.

them simultaneously. such activity is also constant in

there are several examples of essential oils like that

periods of heavy rain; the time of activity depends

of rose (Rosa damascene), patchouli (Pogostemon

on the kind and thickness of the membrane, which

patchouli), sandalwood (Santalum album), lavender

can be altered to suit the desired time of activity

(Lavendula oﬃcinalis), geranium (Pelargonium

and application of the fertilizer (3 to 18 months). the

graveolens), etc. that are well known in perfumery

intensity of release also depends on the temperature:

and fragrance industry. other essential oils such as

the release is faster in periods of intensive plant growth

lemon grass (Cimbopogon winteriana), Eulcalyptus

when temperatures are higher.

globulus, rosemary (Rosemarinus oﬃcinalis), vetiver

cHAPteR III.

(Vetiveria zizanoides), clove (Eugenia caryophyllus) and thyme (Thymus vulgaris) are known for their pest control properties. While peppermint (Mentha piperita) repels ants, flies, lice and moths; pennyroyal (Mentha pulegium) wards off fleas, ants, lice, mosquitoes, ticks and moths. spearmint (Mentha spicata) and basil (Ocimum basilicum) are also effective in warding off flies. similarly, essential oil bearing plants like Artemesia vulgaris, Melaleuca leucadendron, Pelargonium

substances could be achieved, such as: • Protection before fast degradation, • Lower level of evaporation, • Lowered concentration is needed, • Long-lasting activity is achieved (Figure 4), • safer and easier handling.

roseum, Lavandula angustifolia, Mentha piperita, and Juniperus virginiana are also effective against various

therefore microencapsulated essential oils could

insects and fungal pathogens. essential oils derived

be efficiency used as pesticides. Because of slow

from eucalyptus and lemongrass have also been

releasing of essential oil lower amount of oils is

found effective as animal repellents, antifeedants,

needed and therefore cost is also reduced. Figure 5 is

insecticides, miticides and antimicrobial products; thus

representing a comparison between conventional and

finding use as disinfectants, sanitizers, bacteriostats,

microencapsulated active substances.

microbiocides, fungicides and some have made impact in protecting household belongings (Kordali, 2005).

Conventional pesticide

Before the development of modern chemical and pharmaceutical industries, the essential oils have been already used in many areas of everyday life, such as

Pesticide wasted

antiseptics and disinfectants in the pharmaceutical and cosmetic applications (antiviral, antibacterial,

Encapsulated pesticide

antifungal). citronella (Cymbopogon nardus) essential oil has been used for over fift y years both as an insect repellent and an animal repellent. combining few drops each of citronella, lemon (Citrus limon), rose (Rosa damascena), lavender and basil essential

Figure 4: Release time of pesticides.

oils with one litre of distilled water is effective to ward off indoor insect pests. the larvicidal activity of citronella oil has been mainly attributed to its

Conventional pesticides

major monoterpenic constituent citronellal. essential

Pesticides no activity

oils derived from eucalyptus and lemongrass have also been found effective as animal repellents,

Pesticides activity

antifeedants, insecticides, miticides and antimicrobial products; thus finding use as disinfectants, sanitizers,

Treatment

bacteriostats, microbiocides, fungicides and some have made impact in protecting household

Pesticides activity

belongings (Zaridah, 2003).

Microencapsulated pesticides

But the essential oils also have shortcomings. since essential oils tend to evaporate quickly and degrade rapidly in sunlight, farmers need to apply the spicebased pesticides to crops more frequently than conventional pesticides. some last only a few hours,

Treatment

Figure 5: Conventional vs. microencapsulated pesticides eﬃ ciency.

compared to days or even months for conventional pesticides. As these natural pesticides are generally less potent than conventional pesticides, they also must be applied in higher concentrations to achieve

CONCLuSIONS

acceptable levels of pest control (science2.0, 2009).

(Micro)encapsulation technologies might be used

By microencapsulation improve efficiency of natural

in agricultural applications such a pesticides and

chapter III.

fertilizers in order to ensure longer releasing time of

Kordali S., Cakir A., Mavi A., Kilic H., Yildirim

active ingredients, to reduce pollution with toxic

A., Screening of chemical composition and

chemicals and to ensure safer handling also for non-

antifungal activity of essential oils from three

professional users.

Turkish Artemisia species, J. Agric. Food Chem., 2005, 53, 1408-1416.

Microcapsules containing essential oil could be efficiently used as green pesticides with longer

Koul O., Walia S., Dhaliwal G.S., Essential Oils

releasing time and less side effects than synthetically

as Green Pesticides: Potential and Constraints,

prepared pesticides. Many essential oils like

Biopestic. Int., 2008, 4, 63-84.

lemongrass, eucalyptus, lavender and rose have been used for many decades ago as insects and animals

Thompson Learning, California, Chapter 9, Pages

repellents. Using encapsulation technology living live

211-216, 2004.

of this essential oils could be extended and therefore increase efficiency and reduction of cost could be achieved.

Miller G. T., Sustaining the Earth-6th edition,

Science2.0, 2009, Killer Spices - Essential Oil Pesticides May Be Ready To Replace Deadly Organic Kind, online: http://www.science20. com/news_articles/killer_spices_essential_oil_

References 1.

Behles J., Johnson N., Mulqeen P., Siverthorne J., Tovey I., Coating Compositions for Pest Control, WO2007019237, 2007.

Benita S., Microencapsulation: Methods and Industrial Applications-Second Edition, Taylor & Francis Group, 2006.

pesticides_may_ 9.

be_ready_replace_deadly_organic_kind, [24.3.2013].

10. Shaviv A., Advances in Controlled Release Fertilizers, Advances in Agronomy, 2000, 71, 1-49. 11. Trenkel M. E., Slow- and Controlled-Release and Stabilized Fertilizers: An Option for Enhancing

Ghosh S.K., Functional Coatings by Polymer

Nutrient Efficiency in Agriculture, Second Edition,

Microencapsulation, Wiley-VCH, Weinheim, 2006.

IFA, Paris, 2010.

Hirech K., Payan, S., Carnelle G., Brujes L., Legrand J., Microencapsulation of an insecticide by

12. Zaridah M.Z., Nor Azah M.A., Abu Said A., Mohd. Faridz Z.P., Larvicidal properties of citronellal

interfacial polymerisation, Powder Technology,

and Cymbopogon nardus essential oils from two

2003, 130, 324.

different localities, Trop. Biomed., 2003, 20, 169-174.

cHAPteR III.

CHARACTERIZATION OF COMPLEX MACROMOLECULES Majda Ĺ˝igon center of excellence PoliMat majda.zigon@polimat.si

INTrODuCTION characterization of polymers is an important field of work for all those who are involved in the research and development of polymers and polymeric materials. An overview of spectroscopic, thermal and separation techniques together with some typical examples will be presented. Modern polymeric materials are complex multi-component mixtures of macromolecules varying in chemical composition, structure and chain length, which makes it necessary to determine, besides average composition, structure and length, also the distribution of the named parameters, since the properties of polymers strongly depend on their heterogeneity (Fig 1). Average chemical composition, structure and functionality are usually determined by spectroscopic techniques (e.g. infrared, IR spectroscopy, nuclear magnetic resonance, nMR, mass spectroscopy, Ms) and molecular weight distribution (by size exclusion chromatography, sec). thermal properties are determined by thermal techniques (e.g., differential scanning calorimetry, Dsc, thermogravimetric analysis, tGA, dynamic mechanical analysis, DMA) (Fig. 2). Distributions of chemical composition, structure and chain length are usually determined by hyphenated techniques such as sec-MALs, sec-IR, Lc-Ms, Lc-sec etc. In this contribution we will present an overview of the listed techniques and typical applications for the characterization of complex macromolecules.

Figure 1. Schematic representation of the molecular heterogeneity of complex polymers (Kilz, Pasch, 2000).

Figure 2. Instrumental techniques for the characterization of complex macromolecules Â

SPeCTrOSCOPIC TeChNIqueS For determination of the chemical structures, best suited are spectroscopic methods, such as infrared (IR) spectroscopy, nuclear magnetic resonance (nMR), Raman spectroscopy, UV-VIs spectrophotometry, mass spectrometry (Ms), gas or liquid chromatography coupled with mass spectrometry (Gc-Ms, Lc-Ms) or infrared spectrometry (Gc-IR, Lc-IR), etc.

chapter III.

IR spectroscopy is one of the most widely used spectroscopic methods in polymer laboratories. Infrared radiation is a part of the electromagnetic spectrum between the visible and microwave regions. Infrared radiation is absorbed by organic molecules and converted into energy of molecular vibration, either stretching or bending. Different types of bonds, and thus different functional groups, absorb infrared radiation of different wavelengths. An IR spectrum is a plot of wavenumber on X-axis vs. percent

Figure 3. Comparison of 1H NMR spectra of PBA-H100 polymers synthesized at different temperatures (Brulc, 2011).

transmittance on Y-axis (2). IR spectroscopy can be used for: (I) identification of samples components by fingerprint method comparing sample and reference IR spectra; (ii) determination of polymer composition; (iii) monitoring the reactions such as polymerization, crosslinking, degradation etc.; (IV) monitoring the formation and scission of H-bonds, etc. NMR exploits the magnetic properties of nuclei, which are excited by an external magnetic field. Any atom with an odd mass or atomic number has a nuclear spin that can be studied by NMR. When the external magnetic field is applied the protons either align with (parallel) or against it (antiparallel). The stronger the applied magnetic field the greater is the energy difference (ΔE) between the parallel and antiparallel states. An NMR signal is created once the radio wave photons supplied match the ΔE of the nucleus. We can observe different nuclei, most often hydrogen and

MALDI –TOF-TOF: MALDI generates high-mass ions by irradiating a solid mixture of an analyte dissolved in a suitable matrix compound with a pulsed laser beam. As the name implies, the laser pulse desorbs and indirectly ionizes the analyte molecules. A shortpulse (a few nanoseconds) UV laser is typically used for desorption. Different wavelengths such as IR have been investigated recently as alternatives. In practice, MALDI analysis consists of two steps: sample preparation and mass spectral analysis. The key to a successful MALDI analysis depends primarily on uniformly mixing the matrix and the analyte. Samples are typically prepared in the concentration ratio of 1:1,04 analyte:matrix in a suitable solvent such as water, acetone, or tetrahydrofuran. A few microliters of this mixture is deposited onto a substrate and dried, and the solid mixture is then placed into the mass spectrometer.

carbon (one-dimensional 1H and 13C NMR spectra) or interaction between the different cores of the same or different types, usually by two-dimensional NMR

Thermal techniques

spectra. Samples can be analyzed in solution or in the

DSC: Differential Scanning Calorimetry (DSC)

solid state.

measures the temperatures and heat flows associated

Applications of NMR spectroscopy for the analysis of polymers: (I) identification of components by comparing the sample and reference NMR spectra or tabulated values for different chemical groups; (ii) average composition of the sample; (iii) microstructure - configuration, tacticity, branching etc.; (iv) calculation of the number average molar mass, Mn; (v) study of hydrogen bonds formation; (vi) dynamics of polymer chains; (vii) monitoring of the reactions - polymerization, etc. Figure 3 shows the 1H NMR spectra of poly(β-benzyl

with transitions in materials as a function of time and temperature in controlled atmosphere. These measurements provide qualitative and quantitative information about physical and chemical changes involving endothermic or exothermic processes or changes in heat capacity. We can measure: (i) glass transitions, (ii) reaction kinetics, (iii) melting and boiling points, (iv) rate and degree of cure (v) crystallization time and temperature, (vi) degree of crystallinity, (vii) specific heat capacity, (viii) enthalpies of fusion, enthalpies of reactions (ix) oxidative/thermal stability, purity of material etc.

L-aspartate (PBA) during reaction, at higher reaction

TGA: Thermogravimetric analysis measures the amount

temperatures. In the PBA polymerizations higher

and rate of change in the weight of a material as

temperatures obviously facilitate the formation of the

a function of temperature or time in a controlled

side products. However, traces of its presence can be

atmosphere. Measurements are used primarily to

detected even at lowered temperature (Fig. 3).

determine the composition of materials and to predict

cHAPteR III.

their thermal stability at temperatures up to 1000 °c.

the characterization of complex polymers is reflected

tGA can characterize materials that exhibit weight

in: (i) dissolution on a molecular level, (ii) detection

loss or gain due to decomposition, oxidation, or

of non-size exclusion mechanisms, (iii) degradation

dehydration.

studies (Fig. 4), (IV) monitoring the course of reaction (Fig. 5), side reactions etc.

changes in sample properties resulting from

RI chromatograms

changes in five experimental variables: temperature,

LS chromatograms Chromatograms

Chromatograms

time, frequency, force, and strain. DMA measures

0.0 3

0.3 reflux 0.5 min 2 min 4 min 6 min 8 min 10 min

viscoelastic properties of materials: elastic modulus e’’), damping coefficient (tan delta) as a function of time, temperature, frequency or complex modulus,

0.2 RI Response

(storage modulus, e’), viscous modulus (loss modulus,

reflux 0.5 min 2 min 4 min 6 min 8 min 10 min

0.0 2 LS Response

DMa (Dynamic mechanical analysis) determines

0.1

0.0 1

transition points (alpha, beta, gamma), glass transition temperature, stress relaxation.

SeParaTION TeChNIqueS

0.0 6.0

7.0

8.0

9.0

10.0

7.0

8.0

9.0

10.0

Volu me (mL)

Figure 4. SEC curves of poly(hydroxy butyrate) in chloroform after different annealing times; left: differential refractive index detector and right; light scattering detector (Žagar, 2004).

one of the key issues in the characterization of

Polymer

polymers is, how large the macromolecules are. size is expressed by the molar mass and hydrodynamic

0.0 0 6.0

Volu me (mL)

200 nm

Associates

Monomer

volume level of polymerization. Due to the statistical nature of the processes of polymerization polymers are mixtures of molecules of different sizes. therefore, we are talking about the distribution of molar mass. With exclusion chromatography - sec (also gel permeation chromatography, GPc) we determine the distribution of molar mass or individual molar mass average much faster than the above-mentioned

Figure 5. SEC-MALS chromatograms of poly(�-benzyl L-aspartate) homopolymer after 1.5 h, 3 h and 24 h. - - - LS response at angle 90° and ¾ DR response (Brulc, 2011).

methods. the basis of the method is the separation of molecules according to their size or, more precisely, a hydrodynamic volume in the chosen solvent. separation is achieved on the basis of selective

reFereNCeS

diffusion of molecules in the pores and out of the pores.

1. Kilz, P., Pasch, H. enc. Anal. chem., John Wiley &

small molecules pass through the pores, medium

sons, 7495–7543,2000.

molecules penetrate only part of the pores, while large molecules (larger than the pore size) traveling past the pores, are said to be excluded. Larger molecules are eluted faster from the column than smaller ones.

2. http://orgchem.colorado.edu/spectroscopy/irtutor/ tutorial.html 3. Brulc, B., Žagar, e., Gadzinowski, M., slomkowski, s.,

Light scattering is a non-invasive technique for the

Žigon, M. Homo and block copolymers of poly(β-

characterization of synthetic polymers, biopolymers

benzyl-L-aspartate)s and poly(homo and block

and proteins in solution. It is absolute technique and,

copolymers of poly(b-benzyl-L-aspartate)s and

when coupled with sec (sec-MALs), it gives absolute

poly(g-benzyl-L-glutamate)s of different architectures.

molar masses and weight average molar mass, Mw.

Macromol. chem. Phys. 212: 550-562, 2011.

A reversed-phase liquid-adsorption chromatography

4. Žagar, e., Kržan, A., sec-MALs characterization

(RP-LAc) can be combined with sec into a two-

of microbial polyhydroxyalkanoates,

dimensional liquid chromatographic system (RP-Lc ×

Biomacromolecules 5: 628-636, 2004.

sec 2D Lc) to simultaneously determining the variation in composition and molar mass (Šmigovec Ljubič, 2012). Usefulness of a hyphenated technique sec-MALs for

5. Šmigovec Ljubič, t., Rebolj, K., Pahovnik, D., Hadjichristidis, n., Žigon, M., Žagar, e., Macromolecules 45: 7574−7582, 2012.

chapter III.

AGING CHARACTERIZATION OF POLYMERS Gernot Oreski1*, Kenneth Möller2, Gerald Pinter3 Polymer Competence

Center Leoben GmbH 2

SP Technical Research Institute of Sweden 3

Chair of Materials

Science and Testing of Polymers, University of Leoben oreski@pccl.at

he aim of these investigations was to identify and evaluate appropriate degradation indicators for polymeric materials in order to characterize and assess the aging behavior and to predict the lifetime of materials. Therefore,

the influence of the relevant load parameters ultraviolet radiation, temperature and humidity on the degradation behavior of selected polymeric materials had to be determined. A test program concerning six accelerated aging tests was set up and a comprehensive study of five different polymer films and laminates materials and their degradation behavior was done. Therefore, the material properties and the aging behavior were characterized by infrared (IR) spectroscopy in attenuated total reflection mode (ATR), by UV/VIS spectroscopy by dynamical mechanical analysis (DMA) and by tensile tests. Different degradation indicators were derived from the characterization methods and explicitly discussed. With the definition of reasonable end-of-life criteria, these degradation indicators serve as input data for lifetime modeling and assessment.

Experimental Five different polymer films and laminates were selected and investigated (Table 1). A test program concerning six accelerated artificial ageing tests was work out. The aim of the accelerated ageing tests is to determine the influence of the relevant load parameters such as temperature, humidity and ultraviolet (UV) radiation on the degradation behavior of the selected materials. The material properties and the aging behavior was characterized by infrared spectroscopy in attenuated total reflection mode (ATR), by UV/VIS spectroscopy, by differential scanning calorimetry (DSC), by dynamical mechanical analysis (DMA) and by tensile tests.

Table I: Investigated PV Encapsulation Materials

name

Composition

thickness

EVA

Ultra fast cure ethylene vinyl acetate

1085µm

Ionomer 1

Ethylene ionized acrylic acid copolymer

470µm

Ionomer 2

Two layer films, front: ethylene meth acrylic acid copolymer; back: ethylene acrylic acid/ acrylate terpolymer

600µm

TPT

PVF-PET-PVF multilayer film

170µm

Polyester

PET-PE multilayer film

310µm

chapter III.

Results and Discussion

Table II: Accelerated weathering tests.

Test no.

temp

humidity

A comprehensive description of the degradation

85°C

85%RH

behavior of these materials have already reported

65°C

85%RH

85°C

30%RH

different degradation indicators. These indicators

65°C

60%RH

60W/m²

were derived from the characterization methods and

85°C

26%RH

60W/m²

85°C

26%RH

120W/m²

elsewhere [1,2], so in the following this paper concentrates on the derivation and evaluation of

explicitly discussed on one exemplary material. In previous studies it has been shown that tensile testing is the most versatile of the applied characterization methods in describing the aging

FTIR analysis was done in transmittance and in the attenuated total reflectance (ATR) mode, using a Spectrum GX FTIR spectrometer (PerkinElmer, Waltham, USA) with a Pike Miracle Micro-ATR device (Pike Technologies, Madison, USA). The ATR were measured spectra from 4000 to 650 cm-1. The UV/VIS/NIR

behavior [3,4]. Strain-at-break and stress-at-break values are very sensitive to changes in molecular mass of the polymer and therefore sensitive to chemical aging. Furthermore, both values correspond well with material failure. Figure 1 shows exemplary stress-strain curves of TPT.

measurements were carried out using a Lambda 950 UV/Vis/NIR spectrometer with an integrating sphere to measure hemispherical and diffuse transmittance

unaged aged

Spectra were recorded from 250 to 2500nm. To characterize the thermo-mechanical properties DMA was done in tensile mode by using a DMA 861e (Mettler Toledo, Schwerzenbach, Swiss). A sinusoidal

stress [MPa]

and reflectance spectra (PerkinElmer, Waltham, USA).

x x

load was applied with a frequency of 1 Hz. The gauge length was 19.5mm. The scans were run in a temperature range from –60 to 150°C at a heating

strain [%]

rate of 3K/min. Thermal analysis was carried out using a Mettler DSC 821e instrument (Mettler Toledo GmbH, Schwerzenbach, CH). Thermograms were recorded under static air from –60 to 300 °C at a heating rate of 20 K/min. In a second run, to identify irreversible effects, samples were heated up from –60 to 150°C, cooled down back to 60°C and again heated up to 150°C. Melting point and melting enthalpy were evaluated according to ISO 11257-2 and ISO 11257-3. The degree of crystallinity was determined as the ratio between the melting enthalpy of the sample and the melting enthalpy of the 100% crystalline polymer. Tensile tests were carried out with a screw driven universal test machine (Zwick Z010 Allround-Line, Zwick, Ulm, D) at 23°C according to EN ISO 527-3. Rectangular specimens of 100mm in length and 15mm in width were cut prior to exposure using a device with fixed razor blades and rotating sample. The test speed was 50mm/min. From a total of at least five specimens for

Figure 1: Stress-strain curve of an unaged and aged TPT.

Two different phenomena can be observed during accelerated aging of the investigated films. In the preyield and yield region at strains below 25%, changes in mechanical properties like elastic modulus or yield stress are predominantly associated with physical aging, i.e. changes in polymer morphology. Postyield effects like changes in the ultimate mechanical properties (strain-at-break, stress-at-break) are a very sensitive indicator for chemical aging, mostly changes in the molecular mass. For all investigated polymer films a clear influence of the stress factors UV radiation, temperature and humidity on the ultimate mechanical properties was observed (s. Figure 2).

each test series, average numbers for elastic modulus

After all tests a significant decrease in strain-at-

(E), stress-at-break (S b) and strain-at-break (eb) were

break and stress-at-break values was determined.

deduced.

The embrittlement can be attributed to chemical

chapter III.

aging. Generally, UV radiation in combination with

increase in absorption and therefore yellowing can

high temperature (85°C) showed the biggest impact

be found. The drop of hemispherical transmittance in

on the mechanical properties of all investigated

the visual region can be assigned to the formation of

materials, as the strongest decrease in both, strain-

chromophoric degradation products, mainly C=O and

at-break and stress-at-break values, has been

C=C double bonds, which absorb light in the region

measured after Tests 6.

between 250 and 450nm. Usually, the transmittance values Th of a polymer film

strain-at-break [%]

200

Test 1 Test 4

Test 2 Test 5

Test 3 Test 6 TPT

150

for outdoor applications is calculated by weighting the measured spectra with the AM1.5 solar spectral irradiance function between 300 and 2500nm.

∫ T (λ ) × AM 1.5(λ )dλ h

Th =

50 0

(1)

2500

100

300

2500

∫ AM 1.5(λ )dλ

300

1000 2000 3000 4000 5000

aging time [h]

Due to the observed simultaneous and competing processes of yellowing and loss of UV absorber the calculated transmittance values exhibited only

Figure 2: Strain-at-break values as a function of aging time for TPT.

small changes and remained rather constant after 5000h of aging. This behavior, which was observed for all investigated transparent films, limits the use

UV/Vis/NIR spectroscopy in general is a powerful

of hemispheric transmittance value weighted by

characterization technique, giving information on

AM1.5 over the whole solar range of wavelength as a

the optical properties like transmittance, reflectance,

degradation indicator. Therefore, a separation of the

absorbance or scattering of materials. Next to

wavelength regions is necessary in order to obtain

the characterization of these basic properties,

appropriate degradation indicators.

transmittance and reflectance spectra are a very sensitive indicator for chemical aging and the efficiency

The UV region between 295 and 400nm serves as a

of UV absorbers and light stabilizers. Fig. 3 shows the

measure of the efficiency of the UV absorber (UVA)

hemispheric transmittance values of unaged and aged

and light stabilizers in the polymers. Furthermore the

Ionomer 1 after exposure to 85°C and 85% RH.

UVA retention can be assessed using the absorbance

1.00

(2)

A = − log(Th )

0.75

Figures 4 and 5 show the UV absorbance and visual transmittance values of Ionomer 1 as a function of

0.50

aging time.

0.25

0.00

unaged aged 300

400

500

600

700

800

wavelength [nm] Figure 3: Hemispheric transmittance spectra of unaged and aged Ionomer 1.

After weathering for the transparent films in general two different processes have been observed. One the one hand, in the UV region below 400nm and decrease in absorption due to loss of UV absorber was seen. On the other hand, in the visual region an

absorbance (295-400nm) [-]

hemispheric transmittance [-]

values A, which are given by

1.50

Ionomer 1

1.25 1.00 0.75

Test 1 Test 2 Test 3 Test 4 Test 5 Test 6

0.50 0.25 0.00

1000 2000 3000 4000 5000

aging time [h] Figure 4: UV absorbance values of unaged and aged Ionomer 1.

chapter III.

After all accelerated aging test depletion and loss

caused by photo-oxidation, the Ford Motor Company

of UV absorber was observed (s. Fig. 4). Within the

introduced a photo-oxidation index (POI) [9]. It

first 500h of accelerated aging, the depletion rate

measures the accumulation of degradation products

is mainly influenced by the temperature. The tests at

by increase in OH region absorbance areas of FTIR

85°C (1,3,5,6) showed a significantly higher depletion

spectra, which are caused by formation of hydro

rate than the tests at 65°C (2,4). As shown in Fig. 5,

peroxide, carboxylic acid and alcohol groups.

a significant decrease in visual transmittance could

Therefore the region from 2200 to 3800 cm -1 was

be observed after Test 1. The same behavior but to a

integrated and the area due to CH2 absorbance

smaller amount was observed for the other two damp

between 2700 and 3050 cm -1 was subtracted to obtain

heat tests (Tests 2 and 3). Similarly to EVA or Ionomer

the OH absorbance area (s. Fig. 6).

2, only small changes in visual transmittance and little yellowing were observed after UV exposure. The transmittance values remained constant after 5000h slightly at Test 6 (85°C / 26%RH / 120W/m² UV).

Th (400-800nm) [-]

0.950

Ionomer 1

0.925

absorbance [-]

at Test 4 (65°C / 60%RH / 60W/m² UV) and decreased

CH peak

OH peak

0.900 0.875

Test 1 Test 2 Test 3 Test 4 Test 5 Test 6

0.850 0.825 0.800

1000 2000 3000 4000 5000

aging time [h] Figure 5: Visual transmittance values of unaged and aged Ionomer 1.

4000

3500

3000

2500

wave number [cm-1] Figure 6: Hydroxyl and methylene stretching vibration region

At different exposure times t, the photo-degradation index is then given by ⎛ Area(OH ) ⎞ ⎛ Area(OH ) ⎞ − ⎜⎜ POI (t ) = ⎜⎜ ⎟⎟ ⎟⎟ ⎝ Area(CH ) ⎠ exp osed ⎝ Area(CH ) ⎠un exp osed

(3)

The above presented data confirm, the UV/Vis spectroscopy is a very useful tool for the definition

The technique is very generic, i.e. it could be used for

of degradation indicators of polymers. Next to the

all kinds of polymers and no a priori information about

basic solar transmittance and reflectance value the

the polymeric system would be needed.

measured spectra are a very sensitive indicator for chemical aging and the efficiency of UV absorbers

The aging behavior, the degradation mechanisms and

and light stabilizers.

the changes in chemical structure of the investigated

Infrared (IR) spectroscopy is one of the oldest and

for EVA and the Ionomers [3, 7, 8, 10 - 18]. But also the

most commonly used spectroscopic techniques for

chemical degradation mechanisms for PET and the

molecular level characterization of materials. It is

fluoropolymers PVF and PVDF for PV encapsulation

perhaps the most important tool in the investigation of

purposes have been investigated in the past. [19].

oxidation and photo-oxidation of polymeric materials.

materials are well described in literature, especially

Figures 7 and 8 show the photo-oxidation indices for

In oxidation and photo-oxidation of polymers the

EVA and Polyester. For all polymers except for Polyester

degradation products contain hydroxyl (-OH) and

a linear increase in degradation products was found.

carbonyl (-C=O) groups. The former forms alcohols,

The strongest increase was seen after Test 6 at 85°C

while the latter form aldehydes, esters, ketones,

and with the double UV irradiance, the smallest after

carboxylic acids, etc. Carbonyl groups absorb

Test 4 at 65°C. It can be assumed, that UV radiation

infrared radiation effectively, which makes infrared

in combination with high temperature levels has a

spectroscopy an excellent tool to follow oxidative

significant bigger influence on the degradation rate

reactions [7,8]. In order to compare degradation

than temperature only. The humidity level seemed to

chapter III.

have less influence on the degradation rate or the POI.

does not indicate material failure [18].

Interestingly, in absolute numbers, for Ionomer 1

TPT laminate showed also a linear increase in POI,

the POI has a maximum value (after 2000h at Test

and like for the encapsulation materials UV radiation

6) of 0.08, whereas EVA and Ionomer 2 exhibit

in combination with high temperature levels

values around 0.4 after 2000 at Test 6. But UV/Vis/NIR

demonstrated the greatest impact on the materials,

spectroscopy and tensile tests showed at least for EVA

showing the fastest degradation rates. For TPT, the

a far better weathering stability and less chemical

POI values correspond better with the tensile test

aging. Also Ionomer 2 demonstrated a slightly better

results than the solar cell encapsulation materials, but

weathering stability, which is not reflected in the POI.

nevertheless some clear differences can be identified. Whereas tensile test indicated only small influence of the irradiance dose on the mechanical properties, as after Tests 5 and 6 nearly the same strain-at-break

0.5

65°C / 60% RH / 1Sun 85°C / 26% RH / 1Sun 85°C / 26% RH / 2Sun EVA

POI [-]

0.4 0.3

absorbance spectra revealed a significant difference in POI between Test 5 and 6. The most significant changes in IR spectra and the

0.2

highest POI values above 40 were found for the PET side of the Polyester laminate. Unlike for all the other

0.1 0.0

and stress-at-break values were measured, the ATR

investigated materials, the increase in POI was not 0

1000 2000 3000 4000 5000

aging time [h]

linear but exponential, leveling of in a plateau at longer aging times. But like before, the strongest increase was found after Test 6, the smallest after

Figure 7: Photo-oxidation index of EVA.

Test 4. The hydrolysis was also reflected in the tensile tests, where strong embrittlement and a significant decrease in ultimate mechanical properties,

65°C / 60% RH / 1Sun 85°C / 26% RH / 1Sun 85°C / 26% RH / 2Sun Polyester

POI [-]

40 30

whereas after Test 6 the strain-at-break value has decreased to nearly 0 already after 125 of weathering, the POI value still increased strongly until 1000h. In general it was found, that the degradation

rates obtained by IR spectroscopy with photooxidation index as degradation indicator, and

10 0

especially after the UV tests was observed. But

by tensile tests with strain-at-break and stress-at0

1000 2000 3000 4000 5000

aging time [h] Figure 8: Photo-oxidation index of Polyester, PET side exposed to UV.

These findings are in good agreement with an older study done at the PCCL in Leoben, where the intrinsic aging behavior of unstabilized EVA and ethylene acrylic acid copolymers (which have the same chemical composition as the ionomers) was investigated. For these materials, after UV exposure the photo-degradation index showed a more or less linear

break cannot be correlated properly. Where for example photo-oxidation indices showed a steady linear increase, tensile tests showed no changes in ultimate mechanical properties, like for EVA, or an extraordinary decrease, like for Polyester. Nevertheless infrared spectroscopy is a very important technique for the characterization of the aging behavior, which provides information of changes of the chemical structure due to weathering and of the amount of formed degradation products. But this information is not linked to material failure like the results obtained from tensile tests.

increase in degradation products from the beginning.

So far, mostly degradation indicators for chemical

But no correlation between POI and the mechanical

aging processes, i.e. changes in the chemical structure

properties like strain-at-break or stress-at-break

of the polymer chain, have been discussed. But also

values was found. Furthermore, unlike the ultimate

physical aging has to be taken into account. It is well

mechanical properties, the photo-oxidation index

known for ethylene copolymers like EVA or ionomers,

chapter III.

that storage at room temperature and exposure to

the first 250h of damp heat exposure and could be

elevated temperatures result in changes in polymer

confirmed by investigating the thermo-mechanical

morphology and therefore to changes in the thermal

properties in the first 250h of damp heat testing with

and thermo-mechanical properties [20-24].

higher resolution. Exposure to UV radiation, especially

Although the elastic modulus of a material can also be determined by tensile tests, DMA is the preferable method. With DMA the elastic modulus can be

in combination with high temperature levels, leads to chain scission and therefore to a decrease in elastic modulus values (s. Fig. 10).

measured as a function of temperature. So, it not only gives information about the material stiffness, but also

4000

or softening of the material (s. Fig. 9). Generally, physical aging is mainly induced by temperature. Introducing UV radiation as an additional stress factor complicates the analysis of the DMA curves, as two competing effects can be observed. On the one hand, the absorbed radiation heats up the polymer, causing physical aging like described

E' (23°C) [MPa]

about thermal transitions like glass transition, melting 3000 2000 1000 0

85°C / 85% RH 65°C / 85% RH 85°C / 30% RH

TPT

1000 2000 3000 4000 5000

aging time [h]

before after damp heat testing. On the other hand, UV radiation also induces chain scission. The decrease in molecular mass result in decrease of the elastic modulus values, as primarily the interlamellar tie

Figure 10: Elastic modulus E’ (at 23°C) of Ionomer 2 as a function of aging time.

molecules and the entanglements in the amorphous zone, which are prominently responsible for the mechanical strength, are cleaved. But also after the damp heat tests with temperature and humidity load

Conclusion

only chemical aging by means of decrease of elastic

Based on these characterization methods, several

modulus can be observed.

degradation indicators for chemical and physical aging of the polymers were identified and evaluated. Photo-degradation indices were determined from unaged aged

IR spectroscopy. This index is sensitive to chemical 0.6

damping factor [-]

elastic modulus [MPa]

1000 100

0.4

0.2

degradation and serves as a measure of the accumulation of degradation products, but is not indicating material failure. A better indicator was found in the solar optical properties obtained by UV/ Vis spectroscopy. By separating the ultraviolet and visible region, on the on hand the retention of UV absorber, which is important for the long time behavior

0.1 -50 -25

0.0 75 100

temperature [°C] Figure 9: Elastic modulus and damping factor of unaged and aged Ionomer 2 as a function of temperature.

of the material, could be assessed. On the other hand, solar transmittance in the visible range of wavelength is sensitive indicator for chemical aging, as it measures the formation of chromophoric degradation products. Moreover, the transmittance is directly linked to module performance.

The obtained results indicate that DMA is a powerful

Strain-at-break and stress-at-break values gained

characterization technique in describing physical

from tensile tests proved to be very sensitive indicators

aging. In general, higher temperature levels during

for chemical aging. Both values correspond well with

exposure caused greater changes in thermal and

material failure. The elastic modulus, measured by

thermo-mechanical properties. The different humidity

DMA, was found to be the most appropriate indicator

levels had only small influence on changes in polymer

for physical aging. All films showed an increase of

morphology. This assumption is supported by the

elastic modulus values over the whole temperature

fact that for all films physical aging occurred within

range due to exposure at elevated temperatures. The

chapter III.

changes in thermo-mechanical properties due not correspond with material failure. With the definition of reasonable end-of-life criteria, these degradation indicators may serve as input data for lifetime modeling.

15. M. Rodríguez-Vázquez, C.M. Liauw, N.S Allen, M. Edge, E. Fontan, Polymer Degradation and Stability 91 (2006) 154. 16. I.C. McNeill, M. Barbour, Journal of Analytical and Applied Pyrolysis 11 (1987) 163. 17. I.C McNeill, A. Alston, Angewandte

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ACKNOWLEDGEMENTS The research work was performed at the Polymer Competence Center Leoben GmbH (PCCL, Austria) within EU-SP6 Integrated Project „PERFORMANCE“ in cooperation with the Chair of Materials Science and Testing of Plastics at the University of Leoben. The PCCL is funded by the Austrian Government and the State Governments of Styria and Upper Austria. Special thanks to G. Wallner, H. Mattausch, B. Hirschmann and A. Lovas for the support within the project.

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