In-situ Polymerization Prepared Si O2 / Poly Vinyl Acetate Copolymer Emulsion

In this paper, with vinyl acetate as main monomers, first of all to low-cost of modified nano silica solusing in situ polymerization of Si O2/poly vinyl acetate composite emulsion were prepared. To systematically study the polymerization in the process of polymerization process, monomer, emulsifier, initiator and nano silica sol and other factors, yield, placed on the performance of the emulsion stability, polymerization and emulsion stability of coating performance of the main reasons are analyzed.Successful preparation of low viscosity, high hardness, good dispersibility, high stability of the nano silicon dioxide composite vinyl acetate emulsion.The experimental results show that when the inorganic nano silica sol in water phase, monomer adding pre emulsion, the preparated composite emulsion is not layered and stability is good, The ideal amount of nano silica sol of the total of monomer is 10.6%, the reaction temperature is 68℃, the initiator KPS of the total amount is 0.59%, using the three kinds of compound emulsifier op-10/SDS/DNS-86 and the proportion of non-ionic emulsifier and anionic emulsifier is 1:4. Therecovery to 92.7% and the stability of the hardness of 2H Si O2/poly vinyl acetate composite emulsion prepared by these conditions. Tensile testing shows that the maximum load of composite emulsion membrane and tensile strength is improved obviously,but the elongation at break are down a bit;DTA tests show that the heat resistance of the composite emulsion increased, the other according to the SEM photos showed that inorganic nanometer silicon dioxide dispersed uniformly, and the latex particle size is ordinary latex particle size is small.In order to make the nano silicon dioxide is more advantageous to combine with polymer and coating,the first to use 3-(methyl acryloyl oxygen) propyl trimethyl silane(KH-570) for the surface treatment of nano silica sol And according to the experiment it is concluded that the best condition of preparation of the nanometer silicon dioxide modified vinyl acetate polymer emulsion, analyzed the result of the experiment.The experimental results concluded that adding 0.25% KH-570, modification temperature 30℃, p H=9, 30 min for nano silica sol modified time the best condition of surface treatment.After modified with silane coupling agent KH-570 the hardness of composite emulsion is prepared and not use KH-570 modified nano silicon dioxide composite emulsion are same for 2H, and the viscosity is moderate, but placed relative to the stability without surface treatment of the nano silicon dioxide composite vinyl acetate emulsion was poor.By scanning electron microscopy can see each other between the latex particle adhesion, exist in the form of aggregate, far more than the nanoscale, dispersivity is without modification of KH-570 compound emulsion is a bit poor.