MODIFICATION OF NATURAL POLYMERS BY THERMO-MECHANICAL PROCESSING
Location: Plant Polymer Research
Title: Solvent-Free Polymerization of L-Aspartic Acid in the Presence of D-Sorbitol to Obtain Water Soluble or Network Copolymers
Submitted to: Polymers and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2009
Publication Date: September 18, 2009
Citation: Shogren, R.L., Doll, K.M., Willett, J.L., Swift, G. 2009. Solvent-Free Polymerization of L-Aspartic Acid in the Presence of D-Sorbitol to Obtain Water Soluble or Network Copolymers. Polymers and the Environment. 17(1):103-108.
Interpretive Summary: This research found that biobased polymers could be made from a corn-based sugar and a common amino acid, for potential use as gelling agents in multiple applications. Biobased, biodegradable water soluble and swellable polymers are needed to replace non-degradable petroleum-based polymers used in applications such as water treatment, absorbents, thickeners, detergents, soil erosion, and seed coatings. This research found that biobased, water soluble and gelling polymers could be made from sorbitol, a corn-based sugar and aspartic acid, a common amino acid. Such sorbitol aspartate copolymers are much larger in size than polymers commonly made from aspartic acid alone and thus have better properties for many uses. This information will benefit scientists in academia and industries who are involved in making new water-based polymers and gelling agents for applications in cosmetics, diapers, controlled release of drugs, etc.
L-aspartic acid was thermally polymerized in the presence of D-sorbitol with the goal of synthesizing new, higher molecular weight water soluble and absorbent copolymers. No reaction occurred when aspartic acid alone was heated at 170 or 200 degrees C. In contrast, heating sorbitol and aspartic acid neat or with ammonium hydroxide gave a mixture of water soluble and insoluble copolymers of polysuccinimide and sorbitol. In the presence of phosphoric acid, sorbitol aspartate ester copolymers having both water soluble and highly swollen gel components were formed. These results indicate that polysaccharides such as sorbitol can readily react to form copolymer ester/amides with aspartic acid and such copolymers may have utility as biodegradable water soluble and swellable polyampholytes.