Figure 1. Γ = 0.2, Subjects/Patients=5, Trials=1,000
Renewable Carbon-based Citric acid-polyol- Cellulose composite materials
Jay Gonzalez Mentor: Ananda S. Amarasekara Department of Chemistry Introduction: The current interest in the use of renewable resources based monomers and feedstocks for the preparation of polymeric materials is due to depleting fossil resources as well as climate change concerns. There are two basic approaches in this area; the first is the development of synthetic methods for the preparation of current monomers from renewable carbon and the second is the synthesis of new generation polymers based on renewable monomers. The second route is more attractive as it avoids the complex synthetic steps required in the conversion of biomass based compounds to current monomers [1]. As a continuation of our research in development of novel renewable polymeric and composite materials we have studied poly esterification of citric acid (CA) with erythritol (ER). Polycarboxylic alcohol CA can react with ER in several reaction modes, where the -OH and -CO2H groups can undergo inter and intra molecular esterifications [2] [3]. We have used the CA : ER 2 : 1 stoichiometric ratio in these experiments expecting complete reactions of all hydroxyl and carboxylic functional groups. The polymerizations were studied by heating with zinc(II)acetate as a catalyst at 120-160 °C. During these attempts in cross linking carboxylic acid groups with hydroxyl groups from citric acid and erythritol it was found that there were incomplete polymerizations. In an attempt to complete the esterification process, we have added 10-20% (w/w) Sigmacell cellulose (DP ~ 100) as a second hydroxyl group source, as shown in figure 1. FT-IR analysis of cellulose added samples showed a decrease in carboxylic acid peaks and improved esterification type cross linking reactions, producing hard composite materials.
OH HO
O OH
HO C
Zn(OAc)2
O
CO2H CO H HO
OH
HO
OCOO O
O=C -O2C
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O OCOCO2
OCO-
