In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry and the Polymer Program of the Division of Materials Research, Professor Stephen Miller of the Department of Chemistry at the University of Florida is developing new types of degradable plastics made from biorenewable sources (bioplastics), such as sugarcane waste. These new types of plastics have shown some success in replacing commercial plastics made from petroleum feed stocks. However, a major barrier to their adoption is the inferior mechanical and degradation properties of most bioplastics relative to the petroleum-derived plastics. Professor Miller and his research group are studying ways to convert inexpensive agricultural wastes or forestry wastes into feedstocks for making new types of bioplastics. Feedstocks derived from such waste streams do not compete with agricultural food sources. They are focusing on chemistry for making plastics that show desirable mechanical behaviors and that degrade under the appropriate environmental conditions. Professor Miller is also providing research training to graduate students and preparing them for future careers in sustainability science and engineering.
Professor Miller is designing and synthesizing new classes of polyesters and polyacetals based on the bioaromatics, vanillin and ferulic acid. Available in large scale from a paper mill, corn stover, or sugarcane bagasse, these bioaromatics are key structural components to achieving high glass transition temperature materials with desirable thermomechanical properties. Strategies being examined to control thermal properties and degradation behavior include use of bioaromatics as polymer pendent groups, the creation of bioaromatic polysilicon acetals, and the copolymerization of bioaromatics with chemically recycled bis-hydroxyethylterephthalate, from post-consumer poly(ethylene terephthalate) (PET). Nature also abundantly supplies isosorbide, ascorbic acid, erythritol, itaconic acid, and dimethylsuccinyl succinate. Professor Miller is also studying ways to prepare polyesters, polyacetals, or polyamides with cyclic motifs present in the polymer main-chain from these bio-based molecules. The resulting polymers are predicted to possess chain rigidity, higher glass transition temperature, and programmable degradability.
