J. Sternberg, S. Pilla
Keywords: designed to be recycled, biobased, molecular zippers, polyurethane
Summary:The crisis of plastic waste in the environment has led to increasing efforts to design recyclable, renewable polymers. The challenge of recycling and up-cycling requires materials specifically designed for re-use through facile conversion technologies. Biomass, and specifically lignin, is an excellent feedstock to utilize in this regard due to its inherent biodegradability and abundance of C-O bonds. Mimicking natures methods, we have designed lignin-derived precursors with extended molecular zippers allowing for the efficient conversion of waste material (~70%) after synthesis. This non-toxic approach makes use of organic carbonates and renewable curing agents to synthesize lignin-derived polyurethane foams, and polyamides for high performing applications. While recycling technologies for thermoplastic materials are in high use, the options for chemically recycling thermoset polyurethanes are underdeveloped. The technology presented here enables the upcycling of waste products to foams and non-porous materials with comparable performance to commercial products.