Synthesis and properties of CO2 copolymer-based waterborne polyurethane with high solid content

A series of CO2 copolymer-based waterborne polyurethanes with high solid content were successfully prepared by using CO2 copolymer diol, isophorone diisocyanate, and dimethylol propionic acid as the donors of hydrophilic groups. In order to obtain of the emulsion with high solid content and good physical property, the synthesis conditions of CO2 copolymer-based waterborne polyurethane were studied. The influence of dimethylol propionic acid content and synthesis process on the physical property of the emulsion was also investigated. Results show that CO2 copolymer-based waterborne polyurethane with high solid content can be synthesized by chain expansion at relatively low temperature. The waterborne polyurethane emulsion particle size distribution was wide. As the content of hydrophilic groups in prepolymer increased, the viscosity and water absorption increased obviously, this is difficult to synthesize waterborne polyurethane with high solid content and low water absorption. Thermal gravimetric analysis shows that the higher the chain extending temperature of CO2 copolymer-based waterborne polyurethane, the higher the thermal decomposition temperature. When the CO2 molar content of CO2 copolymer diol is about 30%, the CO2 copolymer-based waterborne polyurethane has high strength and better water resistance.