Synthesis and Performances of Biodegradable CO ₂ ‐Based Thermoplastic Polyurethanes

A series of thermoplastic polyurethane elastomers (PTPUs) with M n ranging from 25.4 to 35.7 kg/mol were synthesized via prepolymerization in N,N‐dimethylformamide (DMF), using biodegradable oligomeric poly(propylene carbonate) diol (PPCDL) ( M n = 2000 g/mol) as the soft segment and diisocyanates and butane‐1,4‐diol (BDO) as the hard segments. The effect of the blending ratio between 1,6‐diisocyanatohexane (HDI) and 4,4′‐methylenebis(cyclohexyl isocyanate) (HMDI) was systematically investigated. Results show that at an HDI/HMDI molar ratio of 30/70 (H30), the PTPU exhibits balanced tensile properties, good processability, and notable abrasion resistance, maintaining a tensile strength >12 MPa, an elongation at break >200%, and an abrasion index <0.3 after 2000 tester revolutions. These mechanical characteristics provide a foundation for blow‐molded products to withstand burst stress and resist rupture during forming. Furthermore, a 5% weight‐loss temperature( T 5% ) of 230°C and a melt flow index >16 g/10 min satisfy the requirements for high‐temperature shear and parison extrusion in blow molding. This study not only provides guidance for the synthesis of biodegradable polyurethanes but also offers technical support for their application in the field of blow molding.