Incorporation of CO 2 ‐polyols into ester‐based waterborne polyurethane: An effective strategy to improve overall performance

Amorphous structural CO 2 ‐polyol was used to modify ester‐based water‐borne polyurethanes (WPUs), resulting in improved low temperature film forming and comprehensive hydrolysis/oxidation resistance properties. Excellent intact films can be easily formed even at 3°C by adding 5% CO 2 ‐polyol into the ester‐based WPUs (namely PU 5 CO 2 ). Moreover, WPUs modified by CO 2 ‐polyol show superior hydrolysis/oxidation resistance properties than that of control samples based on castor oil or poly(propylene oxide) glycol. PU 5 CO 2 showed significantly enhanced retention tensile strength from 40% to 68.2% than that of pure ester‐based WPU after 5 h immersion in 1.5% NaOH solution, indicating an improved hydrolysis resistance. In addition, the PU 5 CO 2 displayed boosted oxidation resistance property with retention strength increased from 39% to 65%. Notably, the all‐around aging resistance of ester‐based WPUs intensified with an increase of CO 2 ‐polyol content. This work indicates that the CO 2 ‐polyol may be a promising modified material to improve comprehensive hydrolysis/oxidation resistance and low temperature film forming for ester‐based WPUs.