Effect of renewable castor-oil based thermoplastic polyurethane elastomer on the thermomechanical and biodegradation properties of poly (lactic acid)

Poly (lactic acid) (PLA) is an exceptionally promising polymer sourced from natural materials, offering both compostable and biodegradable properties. However, its main problem lies in its limited ability to withstand impacts. To address this limitation, the PLA was enhanced by including thermoplastic polyurethane (TPUCG) by mixing. TPU is synthesized by incorporating biobased castor oil, 1,6 hexanediol as the soft segment polyol, and glycidol end groups to improve compatibility with PLA. In contrast, the concentration of glycidol employed in the synthesis of TPUCG at concentrations is 0.4, 0.7, and 1 mol%. The resulting TPUCGs were mixed with PLA at 5, 10, 20, and 30 % using a melt blending process. The mechanical, rheological, thermal, morphological, and biodegradation properties under composting conditions were investigated. The impact strength of PLA increased by about two times when blended with 30 % TPUCG. Following a 90-day biodegradation study conducted under composting conditions, it was observed that PLA exhibited a weight loss of 71 %, while the blends displayed weight losses ranging from 60 % to 67 %. These results underscore the potential of biodegradable polymer blends for sustainable materials engineering, offering a hopeful future for the packaging application.