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本文根据ESR方法测定的自由基浓度在聚合反应过程中的变化,研究了甲基丙烯酸甲酯以过氧化苯甲酰和二甲基苯胺为引发体系的自由基聚合反应。在反应前期,自由基浓度变化速度远小于引发速度,是一种自由基浓度缓慢变化的假稳态。由死端聚合結果得到引发剂分解速率常数k_d=0.091/mol·min~(-1)(20℃)。引发效率为0.11。由自由基浓度计算了链终止速率常数k_(t0)结果表明:
In this paper, the radical polymerization reaction of methyl methacrylate with benzoyl peroxide and dimethylaniline as initiator system was studied based on the change of free radical concentration measured by ESR method. In the early stage of reaction, the rate of change of radical concentration is far less than the initiation rate, which is a kind of homeostasis in which the concentration of free radicals changes slowly. The initiator decomposition rate constant k_d = 0.091 / mol · min ~ (-1) (20 ℃) was obtained from the polymerization at the dead end. The initial efficiency is 0.11. The chain termination rate constant k_ (t0) was calculated from the free radical concentration. The results showed that: