Reactor Granule And Alloy Technology For Preparation Of Syndiotactic Polystyrene

The reactor alloys of isotactic Polypropylene(iPP)/ syndiotactic Polystyrene(sPS) were prepared by three methods in this thesis:(1) iPP/sPS alloys were prepared by an in-situ polymerization method, in which two metallocene, rac-Et-(Ind)₂ZrCl₂ and Cp*Ti(OMe)₃, were supported on the same carrier, one for propylene polymerization and the other for preparation of sPS.(2) An in-situ blend method was used to prepared iPP/sPS alloys. iPP prepared with DQ catalyst was resolved in the decalin and styrene at 130℃, subsequently a prescribed amount of Cp*Ti(OMe)₃/MAO/TIBA was added to the reactor, in which sPS polymerization was carried out.(3) As a carrier, porous nascent iPP particles prepared with DQ catalyst were mixed with Cp*Ti(OMe)₃ in toluene solution at 50℃. After two hours, dried and got a yellow supported catalyst, which was used to catalyzed sPS polymerization.iPP/sPS alloys prepared by in-situ polymerization and in-situ blend methods showed a substantial miscibility, which was different from the third method that the sPS polymerization was carried out not in the inner pores, but on the surface of iPP particles. With the techniques of DSC and WAXD, the nascent crystallization of the alloys was investigated. The results showed that the nascent crystallite forms of iPP and sPS in the alloys were not changed by the in-situ polymerization. However, the nascent crystallite forms of sPS in the alloys could be changed by the decalin solvent and iPP added. On one hand, decalin solvent don't match with the empty cavity of δ clathre form of sPS, so the more stable β "was obtained at high temperature. On the other hand, the nascent crystallization of iPP might have certain effects on the nascent sPS crystallization and induced δ clathre form of sPS.As a potential engineering plastic material, sPS is still limited by its poor impact strength. Many efforts have been devoted to improve the toughness of sPS, mainly by blending with the rubbery elastomers. In this work, I attempt to improve the toughness of sPS by using the in-situ blend mentioned above. sPS polymerization was carried out with the rubbery (aPP, EPDM, PS-b-EPR) resolved in the styrene. sPS/rubbery (aPP, EPDM, PS-b-EPR) alloys were obtained.It is well known that gelation occurs during the syndiospecific polymerization of styrene with homogeneous metallocene catalysts. We are the first proposed and demonstrated the utility of in-situ supported metallocene catalyst in sPS polymerization in order to overcome it. It was shown to be higher activity with respect to the conventional supported technique, while keeping the better morphology.