In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Stephen A. Miller of the University of Florida will synthesize and characterize a new class of biorenewable polyesters, targeting thermoplastic packaging applications. The desired polymers resemble the aliphatic polyester polyglycolic acid (PGA) and are termed PGA beta. However, the proposed approach avoids the multistep production of glycolic acid currently necessary for PGA synthesis and it avoids fermentation technology upon which polylactic acid (PLA) production depends. The cationic alternating copolymerization of formaldehyde and carbon monoxide is readily adapted to the incorporation of comonomers, allowing for the facile modulation of the thermomechanical properties. Typical comonomers are inexpensive epoxides, which serve to disrupt the structural regularity of the polymeric main-chain, and thus will decrease crystallinity, modulus, and brittleness. Structure-property analyses will provide guidance and predict the best comonomer targets for mimicking the properties of fossil fuel-based plastics. Also, transition metal catalysts will be surveyed for their capacity to moderate the reaction conditions, and a battery of polymer degradation experiments will be conducted to assess the timescale and conditions for safely returning the PGA beta back into the environment.
Traditional commodity plastics are made via well-established routes and have proven material properties. However, the vast majority derives from finite resources, such as petroleum and natural gas, and contributes greatly to the accumulation of waste because of slow degradation behavior. This research addresses these drawbacks in developing a new, sustainable class of plastics. The efficiently designed synthesis relies on feedstocks that can be sourced from biomass, such as forest byproducts and inedible agricultural waste. The properties of the plastics can be finely tuned in order to mimic and replace existing fossil fuel-based plastics. Instead of accumulating in waste disposal sites and in the environment, these plastics will degrade benignly back into the environmentally friendly chemical components.
