Preparation of waterborne polyurethane with high solid content: the crystallinity control of soft segment and the organosilicon modification

Waterborne polyurethane (WPU) with high solid content (50–60%wt) was synthesized by using mixed polyester diol with the different crystalline degree. The crystallinity of the soft segment was controlled by changing the ratio of polyester polyols. The stability and the particle size of the emulsion were analyzed in detail. The mechanical properties, thermal properties, and water absorption of the emulsion film were also investigated. The degree of crystallization of the soft segment had an essential influence on the performance of the emulsion and the film, and the optimal ratio of the soft segment by the control of crystallinity was obtained. Furthermore, alcohol hydroxy silicone oil was used to modify the WPU. The results showed that the introduction of a silicone chain segment could improve the thermal stability and water resistance of the material. The optimal amount of silicone oil was confirmed by adjusting the amount of silicone oil (4%wt).