活性聚甲基丙烯酸甲酯和溴甲基化聚苯乙烯偶合反应制备接枝共聚物

采用基团转移聚合、阴离子聚合以及高分子偶合反应的方法,合成了一种结构明确、链长均匀和分子量可控的聚苯乙烯接枝聚甲基丙烯酸甲酯。主链聚苯乙烯由阴离子聚合得到,并进行溴甲基化。支链活性聚甲基丙烯酸甲酯由基团转移聚合制备。经偶合反应后得到分子量为3×10⁴～7×10⁴、多分散性指数D为1.2～1.4的接枝共聚物。溴甲基化聚苯乙烯和活性聚甲基丙烯酸甲酯的偶合反应活性随分子量的增大而降低,理想的反应温度为-20℃。用¹HNMR、GPC和DSC表征接枝产物。和均聚物相比,共聚物的玻璃化温度较低。

Synthesis of Graft Copolymer by Coupling Reaction of Living Polymethyl Methacrylate with Bromomethylated Polystyrene

A novel well defined graft copolymer(PS-g-PMMA) with control over the length of both backbone and side chain was synthesized by coupling reaction of living polymethyl methacrylate with bromomethylated polystyrene. The backbond polymer was prepared by anionic polymerization of styrene with n-butyllithium followed by bromomethylation using C₈H₁₇OCH₂Br/SnCl₄. The living PMMA was prepared by group transfer polymerization of MMA. The graft copolymers with narrow molecular weight distribution, D=1.2～1.4, at the M_n of around 3×10⁴～7×10⁴were obtained. The reactivity of the BMPS and living PMMA decrease with increasing of their molecular weight, favorable reaction temperature was-20 ℃. Characterization of the product include ¹HNMR, ¹³CNMR, GPCand DSC, comparing with the homopolymer PSand PMMA, the copolymer has a lower glass temperature.