Study of Rate-accelerating of Aluminum Hydroxide,Boric Acid,and(2-Methylpropyl)Boronic Acid for Atom Transfer Radical Polymerization of Styrene

Abstract

通讯作者:[email protected][中文文摘]以2-溴丙酸乙酯(EBP)为引发剂,溴化亚铜(CuBr)为催化剂,N,N,N′,N″,N″-五甲基二乙基三胺(PMDETA)为配体,选择了3种路易斯酸(LA),即氢氧化铝(AH)、硼酸(BA)、异丁基硼酸(MPBA)为加速剂,对苯乙烯(St)原子转移自由基聚合的加速进行了研究.结果表明,在80℃下,氢氧化铝、硼酸、异丁基硼酸对苯乙烯原子转移自由基聚合均具有明显的加速效果,发现当[AH]/[EBP]=5、[BA]/[EBP]=4[、MPBA]/[EBP]=5时,加速效果最为明显,且对分子量的控制效果较好,特别是异丁基硼酸在设计分子量较大范围内仍具有明显的加速,且控制效果好.[英文文摘]The polymerization of styrene was mediated by copper(I) bromide/pentramethyl diethyl-triamine(PMDETA) using ethyl 2-bromopropionate(EBP) as initiator and a catalytic amount of Lewis acid(LA),such as aluminum hydroxide(AH),boric acid(BA),and(2-methylpropyl)boronic acid(MPBA),as a rate-accelerating additive.The polymerization in the presence of LA proceeded in a living fashion indicated by the first-order kinetic plots,with increase of Mn with respect to conversion and the relatively narrow polydispersities and had a apparent rate2enhancement efficiency. It was found that the polymerization was cont rolled well and had significant rate enhancements when the molar ratio of [AH]/[EBP]=5∶1,[BA ]/[EBP]=4∶1 , [MPBA ]/[EBP]=5∶1,respectively. And particularly ,the rate of polymerization of styrene with the optimal ratio of [MPBA ]/[ EBP](5∶1) was remarkably enhanced and a good controllability was maintained in the molecular weight from 10 000 to 100 000