Abstract: The composite emulsion of waterborne polyurethane (WPU) modified by isobornyl acrylate (IBOA) was prepared by emulsion polymerization method. The effects of the dosage of initiator, mass ratio of IBOA to WPU, reaction temperature and holding time on the mass ratio of solid content, monomer conversion rate, water absorption and tensile strength of film were investigated. The optimum conditions were obtained by orthogonal test. Eventually, it was determined that the best preparation conditions of WPU modified by acrylate (WPUA) were: m(IBOA):m(WPU)=1:3, 0.5% APS as the initiator (based on the mass of monomer), reaction temperature 80℃ and holding time 3 h. The chemical structure, mechanical property, water resistance, and other properties of the composite were characterized by FT-IR, TEM and TG, respectively. The structure- property relationship was also discussed. It showed that the average monomer conversion was 97.35%, the average water absorption of WPU modified by IBOA was 5.94%, and its average tensile strength was 27.17 MPa. Moreover, the morphology of emulsion was core-shell structure, and its stability was good. Thermal degradation of the film was caused by two stages including hard segments degradation and soft segments degradation, respectively.

Key words: isobornyl acrylate, waterborne polyurethane, emulsion polymerization