Synthesis And Characterization Of Water-borne UV-curing Polysiloxane Prepolymer

Polysiloxane, a polymer based on silicon oxygen bond, was used in various areas for its excellent properties. With the repaid development of environmental requirements, the water-dilutable resin and UV solidification were attracting more and more attention compared with the solvent-borne polysiloxane. The solvent-borne product accounted for almost all fields in polysiloxane and the water-dilutable polysiloxane was used as coating, such as silicone-acrylic emulsion with emulsion type. However, the research in water-dilutable resin of polysiloxane with emulsion type and UV solidification copolymer was seldom reported.A certain reactive polysiloxane copolymer was synthesized with the hydroxylation of vinyltriethoxysilane, dimethylethoxysilane and diethoxydiphenylsilane. Then, maleic anhydride was grafted onto polysiloxane copolymer and water-dilutable polysiloxane with UV solidification was obtained.The structure of polysiloxane copolymer and water-dilutable polysiloxane with UV solidification were characterized by NMR and FTIR spectra.In this paper, the intrinsic viscosity, yield and hydroxyl content of the silicone copolymer were discussed and the results showed that the optimal conditions were0.5mol/L hydrochloric acid as catalyst,0.1%wt addictive,0.2mol water, pH value of4, temperature of75℃, synthesis time of5h, and vinyl triethoxy silane, methyl diethoxy silane, and diphenyl diethoxy silane ratio of2:1:1.Intrinsic viscosity and yield was analyzed between catalysts,catalyst dosage,reaction time,reaction temperature,the amount of maleic anhydride.Also water-borne UV-curing polysiloxane copolymer and stability of water-soluble was analyzed between the catelyst,the amount of catalyst,reaction time,reaction temperature,the amount of maleic anhydride and a neutralizing agent,according to the result,the optimal conditions was that,p-toluenesulfonic acid as catalyst,in an amount of0.20wt%,the reaction temperature was90℃,the reaction time was7h,maleic anhydride in an amount of1.0mol,triethanolamine as neutralizing agent. The stabilities of polysiloxane copolymer and waterborne UV curing polysiloxane were characterized by GPC. The results indicated that polysiloxane copolymer of colorless transparent liquid had a broad molecular weight distribution and the ratio of molecular weight and molecular weight is about1.9; water-borne UV curing polysiloxane were also colorless transparent liquid with a wider molecular weight distribution and the ratio of molecular weight and molecular weight is almost2.2.The different ratios of maleic anhydride and silicone copolymer were used to graft and the curing effects were characterized by FTIR. The results showed that the minimal water absorption was0.66wt%after72h, the adhesion was two and the hardness was3H with the resin curing agent B coating of2.5wt%and the heat resistance was optimal with the amount of maleic anhydride and silicone copolymer of1:1and the curing agent of0.5%.