Linda Jungwirth Leila Wallisser
A Guid e to
Bioplastics
1
Linda Jungwirth Leila Wallisser
A Guid e to
Bioplastics
Content
What 1. Introducing Plastics 2. Types of Plastic 3. Problems
p. 6 – 15 p. 16 – 21 p. 22 – 23
How 4. What can we do? 1) Bioplastic Recipes
p. 24 – 31
2) Home Composting
p. 32 –43
with Mycelium 3) Conclusion Sources
p. 44 – 45 p. 46 – 47
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Introducing
Plastics
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what are pl astics, andwhy are they
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bad?
Conventional Plastic
We produce 380 million tons plastic per year 50% of this is for single-use purpose Less than 9% of all plastic gets recycled Humans eat over 18 kg of plastic in their lifetime 10 million tons of plastic are dumped in the ocean annually. One garbage truck load every minute
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1 / PET Polyethylene Theraphtalate water bottles polyester fabric cosmetic containers prepared food trays
recyclable
degradation: 450 years
3 / PVC
2 / HDPE
Polyvinyl Chloride
High-Density Polyethylene
garden hose window frames flooring / insulation squeezable bottles
opaque bottles shampoo detergent grocery bags
degradation: 450 years
degradation: 1.000.000 years
toxic
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5 / PP Polypropylene
non-recyclable
caps straws food containers medicine bottles degradation: 1.000.000 years
4 / LDPE Low-Density Polyethylene cling film bread bags squeezable bottles grocery bags degradation: 450 years
7/O Other sunglasses nylon lego CD’s / DVD’s degradation: 1.000.000 years
6 / PS Polystyrene food containers disposable cutlery medicine bottles egg cartons degradation: 1.000.000 years
often toxic
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Bioplastics
Bioplastics are.. (mostly) made from renewable biomass sources (biobased) such as cornstarch, sugarcane or cellulose. and/or biodegradable, meaning they can be degraded by existing microorganisms into natural compounds whilst offering almost the same qualities as conventional plastics like durability, flexibility, etc.
+ they have the potential to “close the loop” (refers to the process of recycling and reusing products without material loss)
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what are biopl astics andwhy are they better? 13
1900-1930: The first rise of (bio)plastics: the first synthetic plastic and the development of new plastics Starting from ~1900, researchers were developing synthetic polymers made from cellulose (Parkesine, cellophane), caseine (Galalith) and petrochemicals (PLA, PHB) Revolutionary discovery: for the first time, human manufacturing was not constrained by the limits of nature. Humans could create new materials In the 1930s, Henry Ford experimented with making soy bean-based bioplastic cars (because of safety and metal shortage)
1930-1989: World War II as a break for biopolymer research WWII necessitated a great expansion of the plastics industry. The need to preserve scarce natural resources made the production of synthetic alternatives a priority. Using the plentiful carbon atoms provided by fossil fuels seemed to be more lucrative than making synthetic polymers from natural substances like cellulose. Therefore, all research and production of most bioplastics stopped. 14
Bioplastic Timeline
1989-now: The second rise of bioplastics: environmental consciousness and new attempts to make bioplastics There were growing concerns about plastics in society: plastic debris in the oceans was first observed, the dangers of chemical pesticides and pollution were exposed. “Plastic” became gradually a word used to describe that which was cheap or fake. Research on alternative polymers were resumed: PLA was now producible from cornstarch PHB can be made by genetically modified plants Bioplastics from seaweed, food waste, wood, insects… and Fungi! But: industrial scale of bioplastics is not yet favorable to conventional plastics
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T ypes of
Plastic
Bioplastics
Bio-Based Polymers Non-
Biodegradable
/ Bio-Polethylene
Conventional Synthesis
/ Bio-Polypropylene
/ Poly (lactic acid) (PLA)
/ Bio-Polyvinyl Chloride / Biobased PET
/ Poly (D-lactice) PDLA From Microorganisms
/ Polytrimethylene
/ Polyhydrocyalkanoates (PHA)
Terephtalate (PTT)
/ Polyhydroxybutyrate (PHB) / BioPBS Biomass Products / Corn-based plastics / Protein-based / Cellulosics
Plastic
Fossil-Based Polymers NonAliphatic Polyesters
1: Polyethylene
/ Polyaprolactone (PCL)
Theraphtalate (PET)
/ Polybutylene Succinate (PBS)
3: Polyvinyl Chloride (PVC) 5: Polypropylene (PP)
Aliphatic-aromatic
6: Polystyrene (PS)
Polyesters
Polethylene (PE)
/ Polybutylene Adipate Theraphtalate (PBAT) Poly (vinyl alcohol) PVOH
Polyurethane (PU) Polyamide (PA)
Degradability Labels All plastics, even conventional petroleum-based plastics, are technically degradable. Given the right amount of time and environmental conditions, they will break into tiny fragments. However, such plastics will never fully return to their “natural” organic state, thus they remain a source of pollution, leaking chemicals and micro fragments into the environment.
Biodegradable Matter can be broken down into its natural components This is done by biological organisms like fungi and bacteria All types of bioplastics that can completely be broken down within a few months are considered biodegradable. There is no limitation of time how log this process might take
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Compostable Can be broken down by natural processes into non-toxic components At 58 degrees in 84 days Biodegredation of minimum 90 percent 90percent of matter must be smaller than 2mm
Home Compostable Can be broken down by natural processes into non-toxic components At 20 to 30 degrees in 365 days Biodegredation of minimum 90 percent 90percent of matter must be smaller than 2mm
Problems
When bioplastics are termed “biodegradable”, it does not mean that they will break down in compost within a few weeks. “Biodegradable” simply means that the material can be broken down into its natural components, but only under very specific conditions. Furthermore, there is no time limit on how long this degradation process must take as a maximum. In Central Europe, the labels “compostable” or “garden compostable” are often used for bioplastics. “Compostable” means that more than 90% of the plastic must have decomposed in an industrial composting plant at 60°C within 6 months. You would think that you can dispose of such a bioplastic in the green bin, however most composting facilities do not have the appropriate conditions and regulations. “Garden compostable” means that the bioplastic can decompose within one year at max. 30°C. Theoretically, you are able to throw this plastic on the compost. However, it is not sure that it will benefit your compost, because bioplastics have hardly any nutrients, but mainly CO2 and water. Most of the commercial bioplastics (if they are labeled according to the standard at all) belong to the first category. Therefore you can not simply put such a bag in the organic waste. In the normal household waste they can hardly be recycled, but burned. Moreover, such bioplastics, which then end up in nature, like all conventional plastics, never degrade. Ultimately, this also means that they end up on the ever-growing, huge plastic islands in our oceans and pollute the ecosystems.
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what are the problems ofbiopl astics? 23
The legal situation regarding the definition, labelling and disposal of bioplastics needs to change. Consumers need more transparency to change their buying behaviour and support correct waste disposal. Composting and recycling plants must have suitable sorting and recycling systems so that bioplastics can potentially be recycled or broken down to their natural compounds. More research into alternative bio-based polymers must take place. Making bioplastics from waste products (e.g. bagasse, mycelium) would be advantageous, because then the production does not compete with the food industry. Be aware of the potential and problems of bioplastics, and spread the word! Make your own bioplastics! Check out the recipes on the next page. 24
What can
we do?
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Biopl astic
recipes
1. Gel atine-Based 100 ml water 17 g gelatine 8 g glycerol + additives
1. Prepare your additive. Solid materials should be clean and dry to prevent mold. 2. weigh all your ingredients accurately and prepare the moulds you want to pour your bioplastic into. You may want to rub them with some oil in case they have no smooth surface. 3. mix the gelatine and the water in a pot and heat on medium/ high heat until just before boiling. In this stage froth with appear 4. Make sure the gelatine is fully dissolved and turn down to low heat. Add the glycerin, stir. Add the additives and stir more. 5. If a lot of froth has formed, you may want to skim it off with a spoon or sieve. 6. Now pour the gelatine mixture into your prepared mould. You should hurry a little because the gelatine hardens quickly, you may have 2-3 min before it solidifies. Leave in the mould until the bioplastic is dry and easy to remove from the mould.
Tips: gelatine has a very low melting point therefore it should not be placed in the oven to dry. If you want to cast a larger flat and need more time for casting, you can warm up your mould beforehand.
2. Starch-Based 100 ml Water 12 g tapioca starch 7 g glycerol 6 g vinegar (5-7%) + additives
1. Prepare your additive. Solid materials should be clean and dry to prevent mold. 2. weigh all your ingredients accurately and prepare the moulds you want to pour your bioplastic into. You may want to rub them with some oil. 3. mix the starch and the water in a pot and add the glycerol and vinegar after. Finally add your additives. 4. Put the solution on medium heat (on your stove) and mix constantly until the water evaporates and your solution turns into a paste. 5. Once solidified remove from the stove and pour into your mould or spread onto a surface. 6. Let it dry for several days (depening on the thickness) until it is not sticky anymore.
Tips: You can speed up the drying process: place the material in the oven at 60 °C with circulating air. The oven door must remain slightly open. No more than 2 hours because the material will crack. I usually air dry the materials for the first 24 hours and then apply pressure with an object or stretch them in an embroidery frame to prevent shrinkage.
3. Al gae-Based 100 ml water 4 g agar agar 6,5 g glycerol + additives
1. Prepare your additive. Solid materials should be clean and dry to prevent mold. 2. Weigh all your ingredients accurately and prepare the moulds you want to pour your bioplastic into. You may want to rub them with some oil in case they have no smooth surface. 3. Mix the Agar Agar and the water in a pot, bring to a boil while stirring gently, to dissolve the agar. 4. When the agar is dissolved completly, lower the temperature to 60 °C (medium heat) and make sure there are no bubbles . 5. Add the glycerol and your additives and let simmer for around 20 minutes while stirring continuously. 6. When the mixture has the consistency of a light syrup, remove from the heat and pour into your mould or onto a surface. Let it dry for a couple of days until you can easily remove it from the mould.
Tips: depending on the thickness you want to cast, you should boil the solution longer or shorter. The thicker the solution, the thicker the final material. The material tends to shrink a lot, so weight it down with an object or stretch it in a frame or tape it to a surface
how can we use mycelium to speedup the d ecomposition process?
Experiment
We conducted an experiment in which we wanted to see to what extent the fungus Pleurotus Ostreatus can degrade bioplastics. Additionally, we tried to modify some bioplastics to potentially bring the Fungi to its optimal growth state. As pre-treatment methods, we have come up with four different procedures for the bioplastics samples that we carried out before we put them into the mycelium screw-top jars: 1. soak in water for 36h, 2. soak in amylase for 36h, 3. soak in fertilizer (nitrogen-rich) for 36h, 4. control – samples were not pre-treated. The types of bioplastics were a blend of PLA + cellulose, (conventional plastic), two different brands of bioplastics labelled as “compostable” and one “home compostable” bioplastic. The result: Not much, but a good start. After 30 days, we did not see much difference to the initial appearance of the bioplastics. However, the PLA + cellulose and the home compostable sample did have a slightly different colour, indicating enzyme activity of the fungi on the polymers. Therefore we believe that more experimental time, a better experimental setup and using different strains of biopolymer-degrading fungi might give further insights.
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Experiment T ypes ofBiopl astic
Compost bag Home-Compostable
Nucao Cellulose-based (Wood)
Compost bag Home-Compostable Pamela Reif Granola Cellulose-based (Wood) + PLA (Sugar)
Cellophane Sugar
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Experiment Setup
Bioplastics in Solution
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Water
Amylase Solution (1:10)
Fertilizer (7% Nitrogen)
36h
Strips of Bioplastics 39
Experiment Mycelium
+ amylase (36h)
+ water (36h)
+ fertilizer (36h)
reference
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Experiment Outcome
Compost Bag 1 (light)
36h Amylase
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36h Water
36h Fertilizer
Cellophane
Compost Bag 1 (dark)
Pamela Reif
Nucao
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Conclusion
The best option of course is to avoid as much packaging as possible. In regards to bioplastics, we as consumers, must be aware of the risk of greenwashing this idea holds. There is still much systemic change that needs to take place for this alternative material to make a large scale impact. However, despite the negative aspects to bioplastics, we mustn’t forget that it is still a step in the direction towards a more sustainable future. The innovation of a material that is even able to decompose and do so in a drastically shorter amount of time is generally a positive and the idea of using bio-based and biodegradable bioplastics to “close the loop” of materials cycles needs to be supported. We believe, there is a huge potential withing biopolymer research, now the system just needs to follow.
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Sources
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https://biobagworld.com/de/umwelt/biologisch-abbaubar-und-kompostierbar/ https://utopia.de/ratgeber/biologisch-abbaubar-kompostierbar-biobasiert-das-ist-der-unterschied/ https://www.umweltbundesamt.de/sites/default/files/medien/421/ publikationen/18-07-25_abschlussbericht_bak_final_pb2.pdf https://www.bundestag.de/resource/blob/410104/34eca17202ee9d7380e1df34946335c8/wd-8-028-15-pdf-data.pdf http://www.bioplastics.ch/EN-13432.pdf https://www.iwks.fraunhofer.de/de/presse-und-medien/pressemeldungen-2018/positionspapier-zu-bioplastik.html https://www.br.de/wissen/bioplastik-echte-alternative-oder-neues-problem-100.html https://www.deutschlandfunk.de/bei-plastik-ist-bio-nicht-automatisch-oeko-100.html Hidayat, A., & Tachibana, S. (2012). Characterization of polylactic acid (PLA)/kenaf composite degradation by immobilized mycelia of Pleurotus ostreatus. International Biodeterioration & Biodegradation, 71, 50-54. doi:https://doi.org/10.1016/j.ibiod.2012.02.007 Sankhla, I. S., Sharma, G., & Tak, A. (2020). Chapter 4 - Fungal degradation of bioplastics: An overview. In J. Singh & P. Gehlot (Eds.), New and Future Developments in Microbial Biotechnology and Bioengineering (pp. 35-47): Elsevier.
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