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以4,4’-二甲氧基二苯胺为原料,过硫酸氢钾复合盐(Oxone)为氧化剂,通过一步反应合成了苯环类氮氧自由基——4,4’-二甲氧基二苯基氮氧自由基(DMDPN),并与引发剂偶氮二异丁腈(AIBN)组成双分子体系进行甲基丙烯酸甲酯(MMA)的调控聚合.用重量法测定转化率、凝胶渗透色谱(GPC)测定分子量及分布.研究了氮氧自由基/引发剂比以及聚合温度对聚合动力学和聚合物分子量及分布的影响,并对得到聚合物进行了再引发反应以及1H核磁共振表征.结果表明该体系下,氮氧自由基与增长自由基之间无明显的氢转移副反应发生,聚合过程中分子量随转化率线性增加,且聚合物末端具有活性,能进行再次链增长,体现出可控/“活性”自由基聚合的特点.确定了最佳氮氧自由基/引发剂摩尔比为1.6∶1、最佳聚合温度为120℃,并在70℃下实现了MMA的调控聚合.
Using 4,4’-dimethoxy-diphenylamine as raw material and oxone as oxidant, a series of reactions were carried out to synthesize the benzene ring nitroxide-4,4’-dimethoxy Diphenyl nitroxide (DMDPN), and the initiator of azobisisobutyronitrile (AIBN) composed of two molecules of methyl methacrylate (MMA) regulatory polymerization.Determination of the conversion by weight method, the gel The molecular weight and its distribution were determined by permeation chromatography (GPC). The effects of the nitroxides / initiator ratio and the polymerization temperature on the polymerization kinetics and the molecular weight and distribution of the polymer were investigated. The reactivity of the obtained polymer and the 1H nuclear magnetic resonance The results showed that there was no obvious hydrogen transfer side reaction between nitroxide and free radical in the system, the molecular weight increased linearly with the conversion rate and the polymer terminal was active in the polymerization process, The results showed that the optimum nitroxide / initiator molar ratio was 1.6:1, the optimum polymerization temperature was 120 ℃, and the MMA Regulatory polymerization.