2024 AIChE Annual Meeting
Biodegradable and Renewable Protein-Based Elastomers
Currently, agricultural industries generate large quantities of byproducts which can be utilized as feedstocks for biomass-based polymers rather than discarded as waste. Proteins are unique in their ability to form stiff structures through extensive hydrogen-bonding. Some of the amino acids in proteins, such as lysine, serine, and threonine, contain functional groups that can initiate the growth of polymer chains from the protein’s surface. We hypothesize that proteins can be copolymerized with soft polyester segments to create elastomers with both high mechanical strength and high elongation at break, combining the stiffness of the proteins with the flexibility of the polymer chains. Our system uses a common dairy byproduct whey protein isolate as the hard domains and δ-lactones, which naturally occur in plants and animal products, as the soft segments. Whey protein is not soluble in the hydrophobic δ-lactones, so we first introduce a surfactant benzalkonium chloride to enable miscibility between the two components. Next, we show that whey protein and δ-lactones can be copolymerized under solvent-free conditions in the presence of the surfactant. Further investigation is needed to identify the copolymerization mechanism as well as determine the effects of protein content and modifications on the mechanical properties of the resulting material. Ultimately, this research contributes to the design of mechanically robust, renewable materials to support the shift toward sustainability.