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首页> 外文期刊>Journal of Applied Polymer Science >BULK POLYMERIZATION OF STYRENE IN THE PRESENCE OF POLYBUTADIENE - THE USE OF BIFUNCTIONAL INITIATORS
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BULK POLYMERIZATION OF STYRENE IN THE PRESENCE OF POLYBUTADIENE - THE USE OF BIFUNCTIONAL INITIATORS

机译：聚丁二烯存在下苯乙烯的本体聚合-双功能引发剂的使用。

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This work experimentally and theoretically investigates the use of bifunctional initiators in the synthesis of high-impact polystyrene (HIPS). The experimental design involved a series of nonisothermal bulk polymerizations of styrene (St) in the presence of polybutadiene (PB). The performance of three commercial initiators [2,5-dimethyl-2,5 bis(2-ethylhexanoyl peroxy) hexane or L-256; 2,5 dimethyl-2,5 bis(benzoyl peroxy) hexane or L-118; and ethyl 3,3 di(t-butyl peroxide) butirate or L-233] were compared to the performance of a standard monofunctional initiator (terbutylperoctoate or TPBO), and to the blank case (i.e., without initiator). From samples taken along the prepolymerization period, the phase inversion point and the 30% conversion point were estimated. For the final product, the free polystyrene (PS) molecular weights and the St grafting efficiency were measured. A mathematical model was developed that predicts the evolution of the MWDs for the free PS, the residual PB, and the graft copolymer, together with the chemical composition distribution for the total graft copolymer. Compared to the monofunctional case, the L-256 initiator induces phase inversion and rubber grafting at low conversions. Also, it shortens the prepolymerization times by around 38%, without affecting the molecular characteristics of the final product. L-118 also shortens prepolymerization time with respect to TBPO; but is not as effective as L-256 or TBPO in promoting rubber grafting. At the polymerization end, the final molecular characteristics are practically independent of the initiator type because most of the polymerization is induced by monomer initiation. Due to its slow decomposition rate, the L-233 initiator is less effective that TBPO for reducing prepolymerization times and for promoting phase inversion. (C) 1996 John Wiley & Sons, Inc. [References: 15]
机译：这项工作在实验和理论上研究了双功能引发剂在高抗冲聚苯乙烯（HIPS）合成中的用途。实验设计涉及在聚丁二烯（PB）存在下的苯乙烯（St）的一系列非等温本体聚合。三种市售引发剂[2,5-二甲基-2,5双（2-乙基己基过氧）己烷或L-256的性能; 2,5-二甲基-2,5-双（苯甲酰过氧）己烷或L-118;将其与3，3二（叔丁基过氧化丁酸乙酯）或L-233]的性能与标准单官能引发剂（过辛酸叔丁基酯或TPBO）的性能以及空白情况（即没有引发剂）进行比较。从沿预聚合阶段采集的样品中，可以估算出相转化点和30％转化点。对于最终产品，测量了游离聚苯乙烯（PS）的分子量和St接枝效率。建立了数学模型，该数学模型预测了游离PS，残留PB和接枝共聚物的MWD的演变以及总接枝共聚物的化学组成分布。与单功能情况相比，L-256引发剂在低转化率下引起相转化和橡胶接枝。而且，它可将预聚合时间缩短约38％，而不会影响最终产品的分子特性。 L-118还可以缩短相对于TBPO的预聚合时间;但在促进橡胶接枝方面不如L-256或TBPO有效。在聚合结束时，最终的分子特性实际上与引发剂类型无关，因为大多数聚合反应都是通过单体引发而引发的。由于其缓慢的分解速度，L-233引发剂在减少预聚合时间和促进相转化方面不如TBPO有效。 （C）1996 John Wiley＆Sons，Inc. [参考：15]

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