Graft Modification Of Nanosilica Surface And Its Application In Rubber And Plastic Materials

Nanosilica has good chemical inertness,compatibility,stability and other advantages,and is widely used.However,nano-silica also has its disadvantages,especially its difficult dispersion and poor compatibility with the matrix,which affects the filling effect and limits its application.Therefore,it needs to be modified.Nanosilica surface with a large number of active silicon groups,is conducive to graft modification.First,a silane coupling agent was used to organically modify the nano-silica to have a surface-initiated polymerization functional group,and then polymerization was initiated by a "grafting from" method to graft polymerization on the surface of the nanosilica particles.The macromolecule chain,and finally the polymer-modified nano-silica core-shell particles,and the core-shell particles and the polymer are further blended to modify the dispersion of the modified nano-silica in the polymer and the polymer Impact.This study mainly includes the following:1.Preparation of nano-silica grafted polyamino acid core-shell particles and its application in nylon modification.Firstly,the nano silica was prepared by the St?ber method,and the amino silica was modified by using 3-aminopropyltriethoxysilane(APTS),a silane coupling agent with an amino terminal at the end;The similarity of the structure,the use of modified silica surface amino-initiated amino acid graft polymerization to obtain poly-glutamic acid modified nano-silica core-shell particles,further core-shell particles and nylon 6(PA6)melt blending Nanocomposites.The size and surface properties of the nanoparticles were analyzed by dynamic light scattering(DLS),transmission electron microscopy(TEM),infrared spectroscopy(IR)and thermogravimetry(TGA)methods.The results showed that the homemade nanosilica had good Dispersibility and particle size controllability,while successfully organically nano-silica surface.By adjusting the feed ratio of nanoparticles and polymer monomers,polyamino acid modified nanosilica core-shell particles with different grafted molecular weights were prepared.The mechanical properties and crystallization properties of the composites were further tested.The results show that the grafting of polyamino acid macromolecular chains on the surface of nanoparticles enhances their dispersibility,and at the same time improves the compatibility of nylon 6 with nanosilica,with the consequent increase in the shell thickness of nanosilica core-shell particles,nylon.The mechanical properties of 6 gradually increase.2.Graft polyisoprene grafted onto nano-silica and its application in wet mixing of natural rubber.In this section,the surface modification of nano-silica used in rubber was studied in depth to improve the dispersion of nano-silica in rubber and its compatibility with rubber.First,the nano-silica was organically modified with a silane coupling agent ?-methacryloxypropyltrimethoxysilane(KH570)so that the surface of the nano-silica was grafted with a double-polymerized double bond.key.Then,the organosilicon dioxide and the isoprene monomer are graft copolymerized in an emulsion by an oxidation-reduction method to prepare a polyisoprene-modified nanosilica emulsion.Finally,a natural rubber/nano silica wet mix is prepared by thoroughly mixing the copolymer emulsion with the natural latex by wet mixing.Transmission electron microscopy(TEM),scanning electron microscopy(SEM),infrared spectroscopy(IR),thermogravimetry(TGA),and rubber processing analyzer(RPA)methods for the microscopic morphology and blending of modified silica The properties were characterized.The results showed that the successfully grafted double bonds on the surface of nano-silica were organicized and the polyisoprene macromolecules were successfully grafted on the surface of nanoparticles by the initiation of double bonds.The test results of the wet compounded rubber show that the polyisoprene-modified nano-silica particles have good dispersibility in natural rubber,and the physical and mechanical properties of the vulcanizate are better than the addition of nano-silica and organic nano-particles.Silica vulcanizate.