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研究了钒(V)—硫脲氧化还原体系在硝酸溶液中引发丙烯腈聚合动力学,发现硫脲浓度对丙烯腈聚合速度关系曲线上出现两次突跃,第一次突跃相当于在[TU]/[V~(5+)]=0.5～1摩尔比,第二次突跃发生在[TU]/[V~(5+)]=3～4摩尔比的位置上。说明在[TU]/[V~(5+)]摩尔比不同的情况下,作为引发种的V~(5+)—TU络合物的结构和引发历程也不相同。本文在此基础上提出了络合引发机理。
The kinetics of polymerization of acrylonitrile initiated by vanadium (V) - thiourea redox system in nitric acid solution was studied. It was found that there appeared two sudden jumps in the curve of thiourea concentration on the polymerization rate of acrylonitrile. The first jump was equivalent to [ TU] / [V ~ (5 +)] = 0.5 to 1, and the second jump occurs at a [TU] / [V ~ (5+)] = 3 to 4 molar ratio. The results show that the structure and the initiation of V ~ (5 +) - TU complexes as initiating species are different when [TU] / [V ~ (5+)] molar ratios are different. Based on this, this paper presents the mechanism of complex triggering.