Core/shell Structure Of The Preparation And Application Of Silicone Rubber Particles

In this paper, the core-shell particles were prepared by the polymerization of butyl methacrylate in the presence of silicone rubber seeded latex. The morphology, structure and properties of the particles were studied, and then the particles were used to modified PP. The main works were as follows:The monomer conversion rate was measured during the preparation of polysiloxane seed emulsion by the gravimetric method. The influence of concentration of emulsifier(SDBS), concentration of catalyst(H2SO4) and reaction temperature on the kinetics of reaction were investigated. The results showed that the rate of the copolymerization was promoted and the monomer conversion was increased as the concentration of SDBS or H2SO4increased and the reaction temperature raised. The apparent reaction order for emulsifier and sulfuric acid was0.49and0.154respectively. The total activation energy of the copolymerization was39.5164kJ/mol.Due to introduction of monomers, the number of functional groups of which is different and adjust the proportion of them, we prepared a series of seed emulsion. Then BMA was used in the subsequent polymerization as the monomer, and a series of core-shell composite emulsion were prepared. After demulsifying, filtering and drying, we got the core-shell particles. The stability of the emulsion was investigated and the structure and performance of the core-shell particles were confirmed by FT-IR, TG, TEM and so on. The results showed that the particles were regular spheres and they had obvious core-shell structure; the concentration of SDBS has a great influence on the stability of the composite emulsion; the results of TG showed that the heat resistance of the core-shell particles can be improved by adding blocking agent and moderate amounts of CH3Si(OMe)3.We took the core-shell silicone rubber particles used for the modification of PP. Different formula of core-shell particles/PP composite materials were prepared by blending and extruding, and the effects of different content of the particles on the mechanical properties, crystallization performance, heat resistance and rheological properties of PP were studied. The results showed that the low temperature toughening effect of the core-shell particles was remarkable; X ray diffraction peak position, intensity and the crystallization process had all changed as the introduction of the core-shell particles; moderate amounts of the particles can improve the heat resistance of PP; SEM photographs showed that the silicone rubber particles could improve the toughness of PP. When the percentage of the particles was4%, the flow activation energy had a minimum value, and the processing performance of PP can be effectively improved.