Synthesis And Characterization Of Modified Silicone-Acrylic Latex

The self-cross linking at ambient temperature hybrid silicone-acrylate emulsion was synthesized by adding functional monomer acetoacetoxy ethyl methacrylate (AAEMA) into acrylate system which consisted of MMA, BA and MAA and then adding KH550 as cross-linking agent after polymerization. The silicone-acrylate emulsion so obtained and its film were characterized by TEM, particle size analyzer, DSC, TGA, FT-IR. The effect of KH550/AAEMA molar ratio on the properties of latex film has been investigated. The results show that the diameter of latex particle is about 100nm having relatively narrow distribution, and the water resistance, ageing resistance, and mechanical properties of latex film are improved. The results show that the latex film exhibits excellent performance when the AAEMA content get to 8-10% of total monomers, and the results show that the water resistance, ageing resistance, and mechanical properties of latex silicone-acrylate film are improved with increase of KH550, and the latex film has excellent performance when the KH550/AAEMA molar ratio get to 3/4.Hexadecane(HD) was successfully used as the co-stabilizer in the miniemulsion copplymerization of acrylate, methacryloxy(propyl) trimethoxysilane(MPS) and acetoacetoxy ethyl methacrylate (AAEMA) in order to protect the silane moieties from hydrolysis and premature cross-linking by reducing their contact with water. Then hexamethylene diamine is added to emulsion as cross-linking agent. The silicone-acrylate emulsion so obtained and its film were characterized by TEM, particle size analyzer, DSC, TGA, FT-IR. The effect of amount of KH570 and AAEMA on the properties of latex film was investigated. The results show that the latex film exhibits excellent performance when the KH570 get to 10-12.5% of total monomers and the AAEMA get to 8-10% of total monomers.Hydroxyl terminated silicone oil was successfully used as the co-stabilizer in the miniemulsion copplymerization of acrylate and methacryloxy(propyl)trimethoxysilane(MPS) instead of other normal co-stabilizer(like HD) and reduce VOC during the latex film formation. Silicone oil did graft into poly-acrylate chain by condensation of Si-OH of silicone oil and Si-OH of copolymer chains. The silicone-acrylate emulsion and its film were characterized by TEM, contact angle analysis. Effects of the amounts of the silicone oil and MPS on the properties of the latex film prepared have been investigated. It was found that the contact angle of the latex film increases with increasing of the amount of the silicone oil, and the gel content and tensile strength of latex film were improved with an increase in the amount of the MPS incorporated into acrylate. The results show that the latex film has excellent water resistance performance when the KH570 get to 12.5% of total monomers and the ration of silicone oil to monomer is 16-20%.Surface treatment of nano-SiO2 can improve its dispersion stability in emulsifier aqueous solutions. The treated nano-SiCVsilicone-acrylate composite latex was prepared by in-situ emulsion polymerization and miniemulsion polymerization, then the effect of nano-SiC>2 on polymerization process and stabilized mechanism of nano-particles in composite latex have been investigated. The experimental results indicated that the miniemulsion polymerization is good than in-situ emulsion polymerization. The results show that the incorporation of nano-SiO2 is helpful to improve the film properties such as mechanical properties, hardness, ultraviolet aging resistance, stain resistance and so on. The amount of the nano-SiO2 is 4-6% of mass monomer.