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以丙烯酸2-(2-溴异丁酰氧基)乙酯(BIEA)为引发剂单体(inimer),丙烯酸甲酯(MA)为单体,Cu0/CuBr2和N,N,N’,N″,N″-五甲基二亚乙基三胺(PMDETA)为催化体系,二甲亚砜(DMSO)为溶剂,在常温(25℃)下通过单电子转移活性自由基聚合(SET-LRP)合成支化聚丙烯酸甲酯.聚合反应过程中,采用气相色谱(GC)、核磁共振(1H-NMR)和三检测体积排除色谱(TD-SEC)等测试手段跟踪分析和表征支化聚合物的结构.研究结果表明,采用SET-LRP方法,铜粉作为催化剂,常温下聚合反应就能快速进行,130 min之内MA的转化率已达99%以上,制备出高分子量支化聚合物.随着反应的不断进行,聚合物支化程度不断提高,相比较同分子量下的线型聚合物其黏度不断下降,Mark-Houwink特征常数α最小可达0.290.此外,低分子量聚合物组分随着反应不断减少,在高单体转化率下,聚合体系中以高支化度的聚丙烯酸甲酯为主.
(BIEA) as initiator, methyl acrylate (MA) as monomer, Cu0 / CuBr2 and N, N, N ’, N “, N” -pentamethyldiethylenetriamine (PMDETA) as the catalytic system and dimethylsulfoxide (DMSO) as the solvent, by single electron transfer living radical polymerization (SET-LRP ) To synthesize branched poly (methyl acrylate) .Polymerizations were monitored and characterized by gas chromatography (GC), nuclear magnetic resonance (1H-NMR) and three-detection volume exclusion chromatography (TD-SEC) The results show that the use of copper powder as a catalyst can rapidly proceed at room temperature with SET-LRP method, and the conversion rate of MA reaches over 99% within 130 min to prepare high molecular weight branched polymer. With the continuous reaction, the degree of branching of polymer increased continuously, the viscosity of linear polymer decreased with the decreasing of molecular weight, and the Mark-Houwink characteristic constant α was as small as 0.290.Moreover, the molecular weight of low molecular weight polymer With the continuous reduction of reaction, the high degree of monomer conversion, the polymerization system with high degree of branching polyacrylic acid based.