共聚单体对MBA凝胶纤维RAFT聚合制备聚合物微米管的影响

Influence of Comonomers on the Transformation of MBA Gel Fibers into Polymer Micro-tubes via RAFT Polymerization

在不同丙烯酸酯类共聚单体存在下,通过可逆加成断裂链转移(RAFT)聚合,将N,N'-亚甲基双丙烯酰胺(MBA)凝胶纤维转化为聚合物微米管.主要研究了RAFT试剂及共聚单体官能度对产物收率及形貌的影响,采用扫描电子显微镜、透射电子显微镜、红外吸收光谱、元素分析和热失重分析等手段分析所得产物.结果表明,适量RAFT试剂的加入有助于形成形貌规整的聚合物微米管;共聚单体的加入可显著提高聚合物微米管的收率,并且随着共聚单体官能度的增加,对收率的促进效果越明显.对比不同链长的二官能度共聚单体对聚合物微米管形貌的影响,发现随着链长的增加,聚合物微米管的管壁增厚.通过在单官能度共聚单体反应体系中加入少量四官能度单体,显著提高了聚合物微米管的收率.

In presence of different acrylate comonomers, polymer micro-tubes were fabricated directly by taking N,N＇-methylenediacrylamide （MBA） organogel fibres as both the templates and monomer source via reversible addition-fragmentation chain transfer （RAFT） polymerization. The influences of RAFT polymerization and the functionality of comonomers on the yields and morphologies of the products were mainly investigated. The morphology, composition and thermal property of the products were analyzed by scanning electron microscopy （SEM） ,transmission electron microscopy （TEM） , Fourier-transform infrared spectroscopy （FTIR） ,element analysis and thermogravimetric analysis （TGA）. The results indicated that polymer microtubes with well-shaped morphology could be obtained by taking suitable amount of RAFT agent. The yield of polymer micro-tubes could be improved significantly by increasing the dosage of the comonomers. As increasing the functionality of the comonomer, the polymerization was enhanced and the yield became higher. As bifunctional comonomers with different chain lengths were used, the wall thickness of the obtained polymer micro-tubes was compared. The wall thickness became thicker with increasing the chain length of the comonomers. Besides,the yield of polymer micro-tubes could be improved significantly by including a small amount of tetrafunctional monomer in the reaction system with monofunctional comonomer.