Synthesis and characterization of improved bio‐based carbon content thermoplastic polyurethane with bio‐aliphatic and petro‐aromatic diisocyanate

Abstract The study involved producing green thermoplastic polyurethanes (TPUs) that were either partially or fully bio‐based. This was achieved through a one‐shot polymerization process using a combination of sebacic acid‐polyester polyol, 1,4 butanediol derived from renewable sources, and diisocyanate. The diisocyanate used included bio‐aliphatic pentamethylene diisocyanate (PDI), petro‐aromatic methylene diphenyl diisocyanate (MDI), and a combination of PDI and MDI. Various methods were employed to characterize the newly synthesized TPUs, which had a weight average molecular weight exceeding 120,000 g/mol. Increasing the content of PDI improves the bio‐based carbon content up to about 97% and increases the pyrolysis onset temperature. An increase in MDI content results in a rise in the complex viscosity, tensile strength, and strain. However, a PDI‐based TPU (P/M_100/0) achieved an excellent phase separation with a tensile strength of 20.7 MPa and elongation of 587.2%, comparable to an MDI‐based TPU (P/M_0/100). Overall, this research demonstrates the feasibility of utilizing partially or fully bio‐based TPUs as a substitute for conventional MDI, with potential industrial applications.