A Monte Carlo simulation algorithm is developed to visualize the impact of various initiator feeding policies on the kinetics of free radical polymerization. Three cases are studied: (1) general free radical polymerization using typical rate constants; (2) diffusion-controlled styrene free radical polymerization in a relatively small amount of solvent; and (3) methyl methacrylate free radical polymerization in solution. The number- and weight-average chain lengths, molecular weight distribution (MWD), and polymerization time were computed for each initiator feeding policy. The results show that a higher number of initiator shots throughout polymerization at a fixed amount of initiator significantly increases average molecular weight and broadens MWD. Similar results are also observed when most of the initiator is added at higher conversions. It is demonstrated that one can double the molecular weight of polystyrene and increase its dispersity by 50% through a four-shot instead of a single shot feeding policy. Similar behavior occurs in the case of methyl methacrylate, while the total time drops by about 5%. In addition, policies injecting initiator at high monomer conversions result in a higher unreacted initiator content in the final product. Lastly, simulation conversion-time profiles are in agreement with benchmark literature information for methyl methacrylate, which essentially validates the highly effective and flexible Monte Carlo algorithm developed in this work.

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半间歇自由基聚合中的引发剂进料策略：蒙特卡洛研究

开发了一种蒙特卡罗模拟算法，以可视化各种引发剂进料策略对自由基聚合动力学的影响。研究了三种情况：（1）使用典型的速率常数进行的一般自由基聚合；（2）在相对少量的溶剂中控制扩散的苯乙烯自由基聚合；（3）甲基丙烯酸甲酯在溶液中的自由基聚合。计算每种引发剂进料策略的数均和重均链长，分子量分布（MWD）和聚合时间。结果表明，在一定量的引发剂下，整个聚合过程中引发剂数量的增加显着增加了平均分子量并加宽了MWD。当大多数引发剂以较高的转化率添加时，也观察到相似的结果。已经证明，通过四次注射而不是单次进料，可以使聚苯乙烯的分子量增加一倍，并将其分散度提高50％。在甲基丙烯酸甲酯的情况下，会发生类似的行为，而总时间却减少了约5％。另外，以高单体转化率注入引发剂的策略导致最终产物中较高的未反应引发剂含量。最后，模拟转换时间曲线与甲基丙烯酸甲酯的基准文献信息相符，这从本质上验证了这项工作中开发的高效灵活的蒙特卡洛算法。在甲基丙烯酸甲酯的情况下，会发生类似的行为，而总时间却减少了约5％。另外，以高单体转化率注入引发剂的策略导致最终产物中较高的未反应引发剂含量。最后，模拟转换时间曲线与甲基丙烯酸甲酯的基准文献信息相符，这从本质上验证了这项工作中开发的高效灵活的蒙特卡洛算法。在甲基丙烯酸甲酯的情况下，会发生类似的行为，而总时间却减少了约5％。另外，以高单体转化率注入引发剂的策略导致最终产物中较高的未反应引发剂含量。最后，模拟转换时间曲线与甲基丙烯酸甲酯的基准文献信息相符，这从本质上验证了这项工作中开发的高效灵活的蒙特卡洛算法。