Synthesis, characterization and degradation behavior of thermoplastic polyurethane from hydroxylated hemp seed oil

Thermoplastic polyurethane based on renewable resource was synthesized from hydroxylated hemp seed oil. Before hydroxylation, the cold-pressed hemp seed oil was initially epoxidized and then hydroxylated in the presence of catalyst using water, ethanol and butanol. The hydroxylated hemp seed oil was used along with 1,1'-methanediylbis(4-isocyanatobenzene), linear polyester diol from caprolactone monomer (CAPA 2200), and chain extender from resorcinol-based aromatic diol (HER (TM)) to prepare seven different polyurethane elastomers. The structural changes in the modified oils and in the newly synthesized TPUs were characterized using FTIR. Similarly, the structural changes during the TPU polymerization at isothermal temperature were monitored by real-time FTIR. The thermal stabilities and the degradation behavior of the synthesized TPUs were investigated using TG and TG-FTIR studies. The presence of hydroxylated hemp seed oil in the TPU structure has decreased the thermal stabilities and also altered the degradation mechanism.