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为了研究甲基丙烯酸-N,N-2-甲基乙胺酯(DMAEMA)原子转移自由基聚合的表观反应级数,应用初级自由基的原子转移化学反应平衡、链自由基的链增长反应以及链自由基的原子转移化学反应平衡等三类基元反应构成的DMAEMA原子转移自由基聚合反应机理,通过建立聚合反应的动力学模型,研究了在DMAEMA原子转移自由基聚合反应的链引发体系中,链引发剂和催化剂的表观反应级数。结果表明,在DMAEMA原子转移自由基聚合反应的链引发体系中,链引发剂EBIB和催化剂溴化亚铜的表观反应级数均为0.8985。研究了在DMAEMA原子转移自由基聚合反应体系中,链引发剂和总的链增长自由基的浓度随单体转化率的变化关系。在聚合反应初期,总的链增长自由基的浓度随单体转化率的增加而急剧增加,当单体转化率达到40%时,总的链增长自由基的浓度近似保持为常数。链引发剂的浓度在反应初期迅速减少,表明在DMAEMA原子转移自由基聚合反应的早期,体系中存在大量的初级自由基,这些初级自由基使得大部分的链自由基在很短的时间内生成。
In order to study the apparent reaction order of atom transfer radical polymerization of N, N-2-methylethyl-methacrylate (DMAEMA), the reaction of primary radical radical transfer by atomic transfer was balanced, And DMAA atom transfer radical polymerization reaction mechanism composed of three kinds of elementary reactions such as atom transfer chemical reaction of chain free radical. By establishing the kinetic model of the polymerization reaction, the mechanism of DMAEMA atom transfer radical polymerization reaction chain initiation system Medium, chain initiator and catalyst apparent reaction order. The results showed that the apparent reaction orders of chain initiator EBIB and cuprous bromide were all 0.8985 in the DMAEMA initiated chain transfer polymerization. The relationship between the concentration of chain initiator and the total chain-growing radicals in the DMAEMA atom transfer radical polymerization system as a function of monomer conversion was investigated. In the initial stage of polymerization, the concentration of total chain-extended radical increased sharply with the increase of monomer conversion. When the monomer conversion reached 40%, the concentration of total chain-extended radicals remained approximately constant. The concentration of chain initiator decreased rapidly in the initial reaction period, indicating that there were a large number of primary free radicals in the system during the early stage of DMAEMA atom transfer radical polymerization. These primary free radicals produced most of the free radical in a very short period of time .