Preparation And Properties Of Polyacrylate Coating Modified By Nano-SiO₂, Polysiloxane And MAP-POSS

Organosilicon has the characteristics both of organic polymers and inorganic compounds.Bringing organosilicon into water-based acrylate paint is an effective way to improve theperformances of water-based acrylate coating. In this paper, three types silicon-containingacrylate paint were synthesized and the propperties were characterized.1. Polyacrylate emulsion coating modified by Nano-hybrid Silica was prepared withIn-situ method. The properties of emulsion and film were determined. The results showedthat nano-SiO₂is uniformly dispersed in the emulsion, and the average particle size ofnano-SiO₂was40–60nm. The latex particle size increases with the addition of nano-SiO₂.When w（nano-SiO₂）=6%, the glass transition temperature of the modified resin enhanced6.3oC, and the heat resistance and hardness of the coating were also improved by nano-SiO₂.2. Diphenyldimethoxysilane was used as the based monomer and methylacryloylpropyl-rimethoxysilane （MAPTMS） as coupling agent to synthesize polysiloxane emulsion. Thepolysiloxane/polyacrylate composite emulsion was prepared. The water resistance, thermalproperty and mechanical property of the coating film were characterized. The results showedthat when w（polysiloxane）=20%, water absorption of the coating film reaches the lowestvalue6.8%. When w（polysiloxane）=10%, the Tgof resin is57.2oC, which is6.6oC higherthan that of pure acrylate.3. Polysiloxane emulsion was used for seed emulsion and polysiloxane/poly（vinylacetate/acrylate） composite emulsion was synthesized. The kinetics of polymerization wasstudied, and the effect of emulsifier concentration （CE）, initiator concentration （CI） andreaction temperature （T） on polymerization rate and monomer conversion were studied.The thermal and mechanical properties of system were also measured. The results showedthat the copolymer apparent activation energy Eais76.0kJ·mol1; polymerization rateRP∝CE0.48CI0.71; w（polysiloxane） is20%, the glass transition temperature of polymersincreases from43.2oC to47.2oC.4. Methylacryloylpropyl polyhedral oligomeric silsesquioxanes （MAP-POSS） wasprepared and the water-based UV curing epoxy acrylate （EA） coating modified withMAP-POSS was synthesized. The curing kinetics of MAP-POSS/EA system was studiedusing non-isothermal DSC method, and its thermal and mechanical properties were alsodetermined. The results showed that the curing reaction process of MAP-POSS/EA system can be described obtained with S-B autocatalytic model. The average apparent activationenergy of reaction is65.42kJ/mol. When the addition of MAP-POSS is12wt%, TgofMAP-POSS/EA system reaches the maximum52.9oC. Heat resistance of resin was alsoimproved.