摘要:以醋酸乙烯酯(VAc)作为聚合单体,偶氮二异丁腈(AIBN),含乙烯基和二硫代酯结构的v-RAFT作为链转移剂和支化试剂,苯为溶剂在70oC下进行可逆加成-断裂转移自由基(RAFT)聚合,制备出超支化聚醋酸乙烯酯,采用气相色谱(GC)、核磁(1H-NMR)进行跟踪测定聚合过程,三检测凝胶渗透色谱(GPC)表征分析超支化聚合物的支化结构。通过研究聚合机理和支化聚合物结构的表明:聚合过程中呈一级线性增长关系,符合活性可控的特征,当反应大概30小时左右单体的转化率就能达到90%以上,基于RAFT试剂含有可聚合的乙烯结构,聚合物的分子量分布随着转化率的提升不断变宽,表明聚合物的支化结构为逐步形成和发展的。根据凝胶渗透色谱(GPC)、核磁(1H-NMR)等手段的检测手段进一步深入研究聚合物的支化结构,表明随着单体的转化率提升,聚合物的支化度不断增加,高支化聚合物的组分不断增加,但聚合物的PDI仍然比较小。
关键词:聚合单体;可逆加成-断裂转移自由基聚合;醋酸乙烯酯
Abstract:Refined vinyl acetate as an initiator monomer , AIBN as catalyst system ,RAFT reagent as a chain transfer agent , Vinyl acetate occer Reversible Addition-Fragmentation Transfer Radical Polymerization at 70oC in Benzene.Using gas chromatography, gel permeation chromatography, nuclear magnetic track determination of the polymerization process , to characterize the branching structure of the polymer .
The studies on Polymerization mechanism and Characterization of polymer morphology:In the process of polymerization , from the kinetic curves can be seen , about 30 hours the conversion rate can reach more than 90%;According to Gel Permeation Chromatography(GPC),nuclear magnetic resonance (1H-NMR) , and other means of detection of Reversible Addition-Fragmentation Transfer radical polymerization (RAFT) in the conversion of changing circumstances, the degree of branching of the polymer is increasing;Polymer with the reaction in the RAFT system, high component increasing , but the PDI of the polymer is still relatively low.
Key words:initiating monomer, Reversible Addition-Fragmentation Transfer radical polymerization, Vinyl acetate.