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首页> 外文期刊>Journal of Applied Polymer Science >Molecular weight development in emulsion copolymerization of n-butyl acrylate and styrene
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Molecular weight development in emulsion copolymerization of n-butyl acrylate and styrene

机译：丙烯酸正丁酯与苯乙烯乳液共聚的分子量发展

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摘要

The seeded emulsion copolymerization of n-butyl acrylate and styrene in a weight ratio of 50/50 was investigated. The effect of the type of process (batch vs. semicontinuous) and the amounts of initiator and emulsifier charged into the reactor on the time evolution of the fractional conversion, number of polymer particles, and weight-average molecular weight (M-w) was analyzed. It was found that the M-w depends to a slight extent on the type of process and the emulsifier concentration and to a larger extent on the initiator concentration. The molecular weight distributions (MWDs) and the gel content of the final latexes were also analyzed. In the absence of chain transfer agents (CTAs), the fraction of gel was higher in the semicontinuous processes. It was also found that the gel content increased with increasing initiator concentration in the recipe. The addition of 1 wt % CTA avoided get formation and led to an important reduction of the M-w. Nevertheless, the MWDs presented a shoulder or even a second peak at high molecular weights that was due to reactions of chain transfer to the polymer. (C) 2003 Wiley Periodicals, Inc. [References: 38]
机译：研究了丙烯酸正丁酯和苯乙烯以50/50的重量比进行的种子乳液共聚。分析了过程类型（间歇与半连续）和反应器中加入的引发剂和乳化剂的量对分数转化的时间演变，聚合物颗粒数和重均分子量（M-w）的影响。已经发现，M-w在某种程度上取决于方法的类型和乳化剂的浓度，并且在较大程度上取决于引发剂的浓度。还分析了最终胶乳的分子量分布（MWD）和凝胶含量。在不存在链转移剂（CTA）的情况下，半连续过程中的凝胶分数较高。还发现在配方中凝胶含量随引发剂浓度的增加而增加。添加1 wt％的CTA避免了形成，并导致M-w的大幅降低。然而，由于链转移至聚合物的反应，MWD在高分子量下出现了一个肩峰甚至第二个峰。 （C）2003 Wiley Periodicals，Inc. [参考：38]

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