Study On Highly Functionalized Modification Of SiO₂ And Preoaration Of Core/Shell Nanacomposite

A new ideal filler,inorganic/organic nano-composite with nano- SiO₂ as hard core and PS,PI or SA/LA as shell,has been designed In this paper.After grafting C=C,-NH₂ groups on surface of SiO₂ by KH570,KH550,the SiO₂/PS,SiO₂/PI core-shell particles as well as SiO₂/SA/LA composite were prepared.Filling KH570 modified SiO₂ into SBR,the reinforcement capacity of it was valued.Nano-SiO₂ was modified with silane coupling agent(KH570) to graft functional group(C=C) on the surface.The influence factors were investigated systemically,which includes modified method and process,content of KH570 in the reaction,the time and proportion of H₂O/KH570 in the hydrolysis process of KH570,ect.TEM,NMR,IR,and TGA were used to characterize the modified surface of nano-SiO₂ and the optimal conditions were determined. The results reveal that the highest grafting degree can reach 17.1%(wt%) on the conditions of toluene refluence,H₂O/KH570 at 0.35/1,hydrolysis for 143 min,and KH570/SiO₂ at 40%.The products were filled into SBR and the results shows that properties of the filled rubber compound,especially the dispersing of filler,were improved greatly.KH570 modified SiO₂ used for nuclear and St or Ip for the monomer, SiO₂/PS,SiO₂/PI were successfully prepared by Seeded emulsion polymerization,on the condition using 30%SDS/OP-10 as emulsifier, multi-step emulsifying before polymerization.It was discussed to determine the optimal polymerization process which includes the influence of emulsifier, ways of monomer filled,and dispersing method of solid particles.In addition,KH550-g-SiO₂ has been obtained and then SiO₂/SA/LA composite particles were prepared.For controlling the unsaturated degree of composite particles,this paper studied the effect of SA/LA ratio.The research of highly functionalized modified-SiO₂,design and preparation of such core-shell particles as SiO₂/PI and SiO2/SA/LA represent an innovation and never been reported by far.