High cis-1,4 Hydroxyl-Terminated Polybutadiene-Based Polyurethanes with Extremely Low Glass Transition Temperature and Excellent Mechanical Properties

A series of polyurethanes have been prepared from hydroxyl-terminated polybutadiene (HTPB) with high cis-1,4 content and commercial free-radical-polymerized HTPB (FHTPB). The mechanical properties of cured polyurethane (PU) samples have been studied by tensile testing and dynamic mechanical analysis (DMA), and their thermal properties have been tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The NCO/OH ratio, chain extension coefficient (r), and microstructure of HTPB and FHTPB have a large influence on the mechanical properties of PUs. Meanwhile, the cyclic tensile testing indicated that the HTPB-based PUs had an outstanding elasticity. Both DSC and DMA analyses showed that the HTPB-based PUs had a glass transition temperature much lower than that of the FHTPB-based PUs. The hydrophobicity of the surface of PUs was verified by measuring their water contact angles.