摘要:为了研究梳形支化PS的支化结构对线形PS流变性能的影响规律，采用大分子引发剂法，将稳定自由基聚合技术与原子转移自由基技术联用，制备了一系列不同支化结构的梳形支化PS，并且将其与工业级PS共混，使用毛细管流变仪研究了梳形支化PS用量、支化密度、支链长度对共混物流变性能的影响。结果表明，以苯乙烯和乙烯基苄基氯为反应单体，BPO为引发剂， HTEMPO为稳定剂，在苯甲醚作溶剂的条件下进行稳定氮氧自由基聚合反应，成功合成了六组不同配比的P（St-co-CMS）大分子引发剂，通过GPC和1H-NMR的表征证明此方法合成的共聚物结构与所设计的结构符合。以P（St-co-CMS）为大分子引发剂与苯乙烯进行ATRP反应，通过控制单体/引发剂配比和转化率来获得不同支链结构的梳形支化聚苯乙烯。通过使用GPC和1H-NMR表征了聚合物的结构，结果表明，ATRP反应具有良好的可控性，所得支化聚合物的支链长度与支化密度跟设计值基本相符。对于梳形支化PS/工业级PS共混体系，随着梳型支化PS用量增加，聚合物熔体表观粘度下降，非牛顿指数变大；随着支化密度增加，聚合物熔体表观粘度下降，非牛顿指数变大；随着支链长度增加，聚合物熔体的表观粘度下降，非牛顿指数变大。 

关键词：梳形支化聚苯乙烯；稳定自由基聚合；原子转移自由基聚合；流动改性剂；流变性能

Abstract：In order to study how the branched structure of the polystyrene affect the rheological properties of linear polystyrene, we employed the macro- initiator method, synthesized a series of different branched structure of polystyrene in the mechanism of NMRP combined with ATRP ,then blend it with industrial-size polystyrene, using capillary rheometer to study how the comb-like polystyrene affect rheological properties of the compound when the dosage of the comb-like polystyrene changed,  the branching density changed or the side chain length changed. It turned out that: using styrene and p-chloromethyl styrene as monomer, BPO as initiator, HTEMPO as stabilizing agent, anisole as solvent, we successfully synthesized six groups of  macro-initiator(P(St-co-CMS))with different proportioning in the mechanism of NMRP, then using GPC and 1H-NMR to characterize the copolymer, we can concluded that the structure of the copolymer correspond with the structure that we designed at first. Then using P(St-co-CMS) and styrene for ATRP reaction, we can obtained the different branched structure of polystyrene by means of controlling the ratio of monomers and initiator both with the convertion rate, then using GPC and 1H-NMR to characterize the comb-like copolymer, it turned out that the ATRP reaction showed controllability and the branching density both with the side chain length correspond with the designed value. For the blending system of comb-like polystyrene and industrial-size polystyrene, it turned out that with the increasing of the additive, the branching density, the side chain length, the apparent viscosity of the polymer blends will decrease, but the value of flow behavior index will increase.

Key words: comb-like polystyrene; NMRP; ATRP; flowing modifying agent; rheological properties