Study On Synthesis Of Copolymer Of Series Of α-MSt And Modification Of CPVC

α-Methyl styrene (α-MSt) is the product of styrene (St) in which the methyl is substituted by aα-H. With the increasing of steric hindrance, the rigidity of copolymer molecular chain increased and the heat resistance improved, too. Moreover, the chain ofα-MSt polymer molecular has large side-phenyl, which makes the distance of the molecular chains increase and the intermolecular forces reduce. It is important to use these merits ofα-MSt polymer to modify plastic materials.In this paper, a terpolymer ofα-Methylstyrene/Acrylonitrile/Methylmethacrylate (α-MSt/AN/MMA), copolymer ofα-Methylstyrene/Methylmethacrylate were synthesized by emulsion method respectively.The mechanical properties, heat resistance and processing performance of the blends of theα-MSt copolymer with CPVC was investigated. The monomer reactivity ratio ofα-MSt/MMA and the miscibility of the blends ofα-MSt/MMA with CPVC were also studied.The terpolymer ofα-Methylstyrene/Acrylonitrile/Methylmethacrylate (α-MSt/AN/ MMA) were synthesized by emulsion polymerization. The optimal reaction conditions were as follows: the reaction time was 10h and reaction temperature was 75℃. The chemical structure of terpolymer was characterized by FT-IR. The miscibility of the terpolymer/CPVC was investigated by DSC. The heat deformation temperature of the blends were studied with the testing instrument of Vicat soft point. The results indicated that the blends of CPVC with the terpolymer showed higher heat deformation temperature and better processing performance, and CPVC had well miscibility with the terpolymer.The reaction conditions ofα-MSt/MMA emulsion polymerization were studied, and the copolymer was characterized by DSC, FT-IR, TG and DSC. The miscibility of the copolymer and CPVC, mechanical properties, heat resistance and processing performance of theα-MSt/MMA copolymer/CPVC were studied. The result showed that the monomer conversion ofα-MSt/MMA copolymer increased with the increasing temperature and reaction. While with the increasing of the content ofα-MSt, the monomer conversion reduced. Theα-MSt/MMA-CPVC blend had good miscibility and the blends showed higher heat deformation temperature and processing performance than CPVC, and the impact performance of the blends were changed slightly than pure CPVC. Compared with the blends of ACR/CPVC,α-MSt/MMA-CPVC had better comprehensive performance.Theα-MSt/MMA copolymer was characterized by 1H-NMR method and the composition of copolymer with low conversion rate(<10%)was determined. The reactivity ratios ofα-MSt and MMA in copolymerization system and the sequence-length distribution of copolymerization were calculated by the Mayo-Lewis integral method and the extended Kelen-Tüdos method. The results showed that theα-MSt and MMA copolymerization system was the non-ideal copolymerization (r1>1,r2<1,r1·r2<1 ) and the reactivity ratios ofα-MSt/MMA copolymerization system is r1 =1.49, r2 = 0.19 when the temperature is 85℃.The monomer increased as theα-MSt increased. The distribution of sequence length ofα-MSt chains in copolymer became wider, and the probability of long-chain ofα-MSt in the copolymers also increased gradually with the increasing of dosage of theα-MSt monomer.The miscibility ofα-MSt/MMA copolymer and CPVC blends were researched by FT-IR, DSC and SEM. The results showed that there were special physical actions betweenα-MSt/MMA and CPVC, which might promote their miscibility and improve the tensile strength of blends.