采用可逆加成一断裂链转移(RAFT)可控/活性自由基聚合方法,以二硫代苯甲酸-2-腈基异丙酯(CPDB)为RAFT链转移剂并以丙烯酸(AA)为单体,在聚丙烯(PP)多孔膜表面进行了等离子体引发的RAFT接枝聚合改性。聚合动力学研究结果表明:聚合反应具有RAFT聚合动力学特征,等离子体处理可以引发RAFT自由基聚合。以傅立叶红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、压汞、水通量等方法,研究了改性多孔膜的表面化学与形态结构及孔结构特征。改性多孔膜表面的接枝率随单体转化率的提高呈线性增长,表面亲水性得到显著改善,同时膜孔径及水通量随接枝聚合时间的提高持续减小。其趋势符合RAFT可控/活性自由基聚合机制,实现了多孔膜膜孔径控制的目的。
A reversible addition-fragment chain transfer(RAFT) graft polymerization method,initiated by the pulsed plasma,was used to modify the surface of porous polypropylene(PP) membrane,with 2-cyanoprop-2-yl dithiobenzoate(CPDB) used as the RAFT agent and acrylic acid as the monomer.The result of the graft polymerization kinetics was in agreement with that of the RAFT polymerization,and the plasma-initiated method was feasible.The surface chemistry,the surface morphology and the porous structure of modified PP membranes were evaluated by Fourier transform minfrared spectroscopy(FT-IR), scanning electron microscope(SEM),mercury intrusion,and water flux measurements.Graft amounts of modified membranes exhibited a linear increase with the increase of the conversion,while pore sizes and water fluxes were decreased continuously with the prolonging of polymerization time.The pore size of the porous PP membrane was regulated by a simple tune of the polymerization time or the monomer conversion by the RAFT graft polymerization.