ARGET ATRP法合成聚氯乙烯接枝丙烯酸丁酯共聚物

以不稳定氯含量高的聚氯乙烯（U-PVC）和氯乙烯-溴代异丁酸烯丙酯共聚物（PVC-co-ABrMP）为大分子引发剂，使用电子转移催化再生原子转移自由基聚合（ARGET ATRP）进行丙烯酸丁酯（BA）的溶液接枝共聚。在固定CuCl₂：三（2-吡啶甲基）胺：辛酸亚锡（摩尔比）时，当CuCl₂用量（相对于氯乙烯链节数）小于0.1%时，BA转化率随CuCl₂用量增加而明显增加；辛酸亚锡与CuCl₂摩尔比大于50时，辛酸亚锡用量对聚合速率的影响较小；相同催化体系用量下，采用PVC-co-ABrMP为引发剂，可获得更高的BA转化率。通过PVC-co-ABrMP酯基水解得到PBA支链，其分子量分布指数为1.29，符合“活性”自由基聚合的特征。接枝PBA对PVC有明显的内增塑效果，PBA摩尔分数为32.75%的PVC-g-BA的玻璃化温度为8.34℃。

Synthesis of poly(vinyl chloride)-butyl acrylate graft copolymer by ARGET ATRP method

The grafting copolymerization of butyl acrylate (BA) onto poly(vinyl chloride) (PVC) was conducted through the method of activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), using PVC with higher labile chlorine content (U-PVC) and vinyl chloride/allyl 2-bromo-2-methylpropionate random copolymer (PVC-co-ABrMP) as an initiator. The polymerization conversion of BA was obviously increased as CuCl₂ concentration (based on number of vinyl chloride unit) increased when CuCl₂ concentration was lower than 0.1%. The increase of BA polymerization rate was not obvious when Sn(EH)₂/CuCl₂ molar ratio exceeded 50. The greater BA polymerization rate and PBA grafting degree were achieved when PVC-co-ABrMP was used as the initiator with the same catalyst. The side PBA chains were cleaved from the ester group of PVC-co-ABrMP and the molecular weight distribution index of PBA was 1.29, verifying the “living” nature of this graft copolymerization. The grafted PBA showed good internal plasticization effect on PVC, and the glass temperature of PVC-g-BA copolymer with 32.75%(mol) PBA was reduced to 8.34℃.