Preparation Of New Hairy PS/PI Microspheres And Its Reinforced Properties In Rubber

Basing on a structural model and design thought of rubber ideal filler(IF), this paper put forward a new way of preparing polystyrene(PS)/polyisoprene(PI) core-shell microspheres which the surface shell polymer chain can be controlled by grafting(graft onto). Filling the PS/PI into SBR matrix, the capability of it was valued.First of all, the PS microspheres which the average diameter was 46nm and the dispersion coefficient was 1.0-1.05 were prepared by conventional emulsion which related to adjusting the ratio of emulsifier compound, the content of crosslinking agent and different feeding techniques. The larger content of divinylbenzene(DVB), the more gels were produced or the more unstable of emulsion system. With the increasing amount of DVB, Tg of PS was increased.Maleic anhydride and acrylic acid were investigated for importing carboxyl groups onto the PS microspheres and acrylic acid as modification was finalized. The method of dropping monomer mixture by semi-continuous was better to graft carboxyl onto the surface of microspheres. The presence of carboxyl groups were characterized by IR and SEM and the content of surface carboxyl was determined by conductometric titration.. With the content of acrylic acid added, the content of surface carboxyl was increasing. When the quantity of AA was 5%, the grafting rate of carboxyl was 57.88%. The PS-COOH microspheres were processed by chloride modification for improving the surface reactivity and the PS-COC1 was prepared. IR confirmed the presence of chloride groups.A series of different molecular weight hydroxyl-terminated polyisoprene which had narrow molecular weight distribution were synthesized by living anionic polymerization method. The hydroxyls were proved by IR and NMR. The 1,4-polyisoprene structure accounted for 65.3% by calculated.The PI-OH chains were grafted onto the surface of PS-COOH microspheres by reaction between groups and a series of different molecular weight PI shell of PS/PI core-shell microspheres were prepared. DSC and IR of these microspheres which were processed by extraction experiments confirmed the chemical connection between shell and core. The method which was preparation of rubber ideal filler by grafting onto achieved the goal of control by designing molecular. The idea is innovative and has never been reported as far.Compared with other ideal fillers, PS/PI hairy microspheres can be better combined with rubber matrix because of the rubbery PI chains which enhance the compatibility of filler and matrix. However, the results of SBR which is filled by PS/PI hairy microspheres is not ideal, but the idea is still an innovative thinking.