Preparation And Properties Of Polysiloxane-acrylate Copolymer Latex With High Solid Content

The combination of polyacrylate and polysiloxane latex appears to possess the advantage of both polysiloxane and polyacrylate latex in overcoming the high cost of polysiloxane or the poor performance of acrylate latex in thermal stability and resisting water, and their correspo-nding latex products have been widely used as coatings, adhesives, rubbers, controlled drug release systems and makeup. In this thesis, the development of emulsion polymerization theory is reviewed, and related new technologies, the synthetic technologies modified by polysiloxane both at home and abroad are also comprehensively reviewed. With discussing the status and development of the polysiloxane-acrylate latex, it could be conclude that it has a broad application prospects. Meanwhile, based on the current development and research in this field, attentions of this study are focused on the way for preparing novel acrylate latex modified by polysiloxane.Anion ring-opening co-polymerization was carried out with octamethylcyclotrasiloxane (D4) and tetramethyl tetravinylcyclotetrasiloxane(D4ⅵ) as organosiloxane monomers, dodecy-lbenzene sulphonic acid(DBSA) as catalyst, nonylphenol ethoxylates(NP-40) and dodecylbe-nzene sulfate(SDBS) as composite emulsifiers, and the stable polysiloxane latex was synthes-ized by this way with high conversion.Polysiloxane modified acrylate latex was prepared pre-emulsificational seed emulsion polymerization with methyl methacrylate (MMA) and butyl acrylate(BA) as main monomers, acrylic acid(AA) as functional monomer, polysiloxane latex as organic monomer, and ammonium persulfate(APS) as initiator, and the stable polysiloxane modified acrylate latex was successfully prepared with both high solid content(>50%), high polysiloxane content(>10%), low emulsifier content(<2.5%).The influence of feeding method, reaction temperature, agitation intensity, the mass ratio of polysiloxane latex during seed latex preparation, the mass ratio of MMA/BA, the type and amount of emulsifier, the amount of initiator, the dosage of AA, the amount of polysiloxane and the mass ratio of D4/D4ⅵ on polysiloxane modified acrylate latex and film properties. By analysis the test to determine the optium conditions:dosage of the initiator was 0.5%, AA content was3%, when the polysiloxane latex content comes to40g, there is no need to add emulsifier, and the reaction temperature was80℃.The microcosmic characteristics of polysiloxane-acrylate copolymer products were characterized by infrared spectroscopy(FT-IR), transmission electron microscopy(TEM) and laser particle size distribution. The products is proven and polysiloxane-acrylate copolymer, which has structure. Meanwhile, the application performance of latex film was tested by the thermal gravimetric analysis(TG), and the tensile properties testing, and the influence of adding polysiloxane on heat-resistance and mechanical properties of the film were studied.