Synthesis Of Alkoxysilane-modified Acrylic Latex For Fiberglass Mesh

Fiberglass mesh had good properties such as high temperature resistance,high strength, low density and so on. So more and more fiberglass mesh were applied in architecture,but the mesh was corrupted by alkali from cement and the strength of fiberglass was poor.By changing the chemical dosage of fiberglass mesh,the alkali resistance could be enhanced,but it made the cost too high.It could improve the abiility of alkali resistance and strength of fiberglass mesh by coating the mesh with em emulsion polymer.Most of the coating were poor strength,easy corroding,bad handle,tackiness and others defects.In this paper,an alkali resistant emulsion binder was prepared by core-shell polymerization and introducing an alkoxysilan to copolymerize with shell polymer.crosslinking agent KH-570 was used to correct these shortcomings in conventional emulsion.A stable copolymer emulsion with high MATS content was prepared by seeded semibatch emulsion polymerization.The hydroscopici -ty of the films of the latexes were tested.The branched large group of MATS can effectivel decrease the surface energy of the films,provide the copolymer excellent water-resistance. Results were as follows:A coating binder was prepared by core-shell polymerization and an organosilicon coppler was copolymerized in it.The emulsion coating had good properties such as softness,ad -hesive resistance,high strength,alkali resistance and was satisfied with the property of product.The performance of the coating binder is mainly influenced by the Tg of core polymer and shell polymer,the ratio of core polymer to shell polymer, the dosage of NMA,the dosage of emulsifiers,the dosage of KH-570.The best technology conditions were as follows:Tg of core polymer-45℃,Tg of shell polymer 20℃,the ratio of shell polymer to core polymer dosage of NMA in core polymer about 1.5%,dosage of KH-570 6.0%,dosage of emulsifiers 3.0%.Alkoxysilane and acrylate were polymerized by means of FT-IR andspectra;The results of DSC tests showed the Tg of the core polymer and shell polymer were -39℃and 24℃, slightly higher than numerical value in theory for the alkoxysilan; By TEM observation,the polymer with core-shell structure was prepared.Stable copolymer emulsions with high silicon content were prepared by seeded semibatch emulsion polymerization,in which KH-570 acted as a crosslinker and MATS [γ-methacryloxy -propyl tris-(trimethylsiloxy)silane] was used as a reactive organosilicon monomer with branched Si-O-Si groups.The properties of the copolymer latex were measured.The property of the water-resistance and adhesive joint strength were improved which crosslinking rate and alkali resistant keeping rate of fiber glass mesh were reduced.