水相原子转移自由基聚合制备PVC-g-BA共聚物

摘要

以不同不稳定氯含量的聚氯乙烯(PVC)为大分子引发剂，CuCl2/三(2-吡啶甲基)胺(TPMA)为催化体系，抗坏血酸(AA)为还原剂，通过水相电子转移催化再生原子转移自由基聚合(ARGET ATRP)制备PVC接枝丙烯酸丁酯(BA)共聚物(PVC-g-BA)，研究聚合条件对BA聚合转化率和接枝率的影响。发现其它聚合条件相同时，采用不稳定氯含量高的PVC为大分子引发剂制备的PVC-g-BA的接枝PBA的平均分子量较低；随着BA单体用量增加，聚合转化率和接枝率增大；随着催化剂CuCl2用量和聚合温度的增加，转化率和接枝率先增加后减小；当PVC 为1.589 g，BA为2.70 g，CuCl2用量为0.0048 g，AA/TPMA/CuCl2(mol)=15/5/1,聚合温度为70℃，可获得BA转化率为56.06%、接枝率为95.14%的PVC-g-BA产物；由于PVC仅部分溶胀于BA，导致PVC接枝不均匀，PVC-g-BA分子量分布出现双峰现象，接枝PBA的分子量大于理论分子量。%　　The grafting copolymerization of butyl acrylate (BA) onto poly(vinyl chloride) (PVC) were conducted through the method of activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) in aqueous phase, using PVC with different labile chlorine contents as the initiator, anhydrous CuCl2/tri(2-pyridylmethyl)amine as the catalyst system, and ascorbic acid (AA) as the reducing agent. It was found that the molecular weight of grafted poly(butyl acrylate) (PBA) is decreased as PVC with greater labile chlorine content was used. The polymerization conversion and grafting degree of BA are increased with the increase of BA concentration. The conversion and grafting degree of BA are increased at first and then decreased with the increase of the concentration of CuCl2 and polymerization temperature. For polymerization system consisted of 1.589 g PVC, 2.70 g BA, 0.0048 g CuCl2, and with AA/TPMA/CuCl2(mol)=15/5/1, the conversion and grafting degree of BA are 56.06%and 95.14%, respectively, as polymerization proceeds for 7 h at 70℃. Due to the partial swelling of PVC in BA, the grafting of BA onto PVC is not uniform, and the resulted PVC-g-BA exhibits bimodal molecular weight distribution.