Synthesis Of Waterborne Polyurethane Grafted With Sericin And Application In Natural Rubber Latex

21st century is the period of the life science and health industry, and health industry has become the world's most active industry. As time passes by, the environmental health of medical materials will increasingly play an important role in the health industry and will be in constant state of development. Study of body safe medical materials have a significant meaning on the protection of human health and promoting the development of human civilization. Natural rubber latex (NRL) as renewable natural resource, possesses excellent mechanical properties. But there exists the problems that the allergy to human skin and surface adhesion of NRL products. Focusing on these problems, we introduced sericin proteins and waterborne polyurethane, the former possess good biocompatibility and the latter possess excellent physical and mechanical properties. We prepared blending latex and film materials by use of heterocoagulation method. We researched the influence of blending ration on the latex structure and film properties through a variety of testing and characterization methods.First we synthesized graft copolymer latex with sericin and waterborne polyurethane, exploring the best properties of graft latex through the change of raw materials ratio. By means of characterization technique with FTIR and 13CNMR, we proved that sericin had successfully grafted to the polyurethane prepolymer. Then through the heterocoagulation method, on the condition of appropriate pH, natural rubber latex was blended with graft copolymer to study the influence of different blending ratio on properties of latex and films. Furthermore, we made test of cytotoxicity, skin irritatin, extracted protein to characterize irritability of modified films.The results showed that:The particle of modified latex through heterocoagulation blending showed obvious core-shell structure. The core layer was natural rubber latex particle, and the shell layer was graft copolymer particle. Compared with the film of NRL, there existed no crackles on the surface of modified films. Furthermore, the add of chitosan to blending latex improved the smoothness of modified films. The crosslink density, oil resistivity and tensile strength of modified films was better than that of NRL film. The modified films showed no apparent cytotoxicity. Through the test of skin irritatin and content of extracted protein, modified films improved the anaphylactic reaction compared with the NRL film. Meanwhile, the modified films showed certain good function to human skin.