UC San Diego

The market for sustainable, biodegradable materials is steadily increasing as the world brings attention to the accumulation of plastic waste. Synthetic, polymeric materials that can be molded and shaped define plastic; it is estimated that 11 million metric tons of plastic are thrown into the ocean yearly.1,2 Certain plastics, such as PET or Styrofoam, are not biodegradable, as their chemical structure can resist attack from microorganisms and the natural environment. 3,4 Although non-biodegradable, these plastics can be synthesized using recycled or bio-based materials, categorizing them as sustainable. Other plastics, such as polyurethanes and polycaprolactones, have a chemical structure that can be subject to attack by microorganisms and break down naturally. Biodegradable plastics can also be synthesized from recycled or bio-based materials, classifying them as sustainable, biodegradable plastics. This thesis demonstrates analytical techniques to observe the chemical biodegradation of sustainably synthesized thermoplastic polyester polyurethane resins (TPU) by FTIR, SEM, and NMR. FTIR was an instrument used to observe the urethane functional group coming apart into their respective biodegradation products. NMR was used to identify biodegradation products and observe changes to the remaining polyurethane skeleton due to degradation. SEM was used to monitor physical changes to the TPU, including cracks, crumbles, and microorganism growth.