Trouble-free combination of ω-alkenylmethyldichlorosilane copolymerization-hydrolysis chemistry and metallocene catalyst system for highly effective and efficient direct synthesis of long-chain-branched polypropylene
Trouble-free combination of ω-alkenylmethyldichlorosilane copolymerization-hydrolysis chemistry and metallocene catalyst system for highly effective and efficient direct synthesis of long-chain-branched polypropylene
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DOI：
10.1016/j.polymer.2022.125327
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发表时间：
2022-09
期刊：
影响因子：
4.6
通讯作者：
Yuanjie Wang;Yawei Qin;Jin‐Yong Dong
中科院分区：
文献类型：
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作者：
Yuanjie Wang;Yawei Qin;Jin‐Yong Dong
采用ω-烯基甲基二氯硅烷共聚-水解（ACH）化学和茂金属催化体系相结合的方法，高效合成了长支链聚丙烯（LCB-PP）。潜在的副反应，二氯硅烷-甲基铝氧烷（MAO）双取代反应，被发现是缓慢发生的，并在很大程度上通过稍微增加反应物上的烷基取代基的空间位阻抑制。因此，对于链烯基链长增加一些的5-己烯基甲基二氯硅烷和7-辛烯基甲基二氯硅烷，茂金属催化ω-烯基甲基二氯硅烷/丙烯共聚合主副反应竞争动力学涉及二氯硅烷的（外消旋-Me 2Si-[2-Me-4-Ph（Ind）] 2 ZrCl 2）-改性的MAO络合物-MAO双取代反应可使共聚反应向主反应方向转移，使副反应的影响不明显。合成的LCB PP分子量分布较窄，LCB结构为H型，交联键为1，2-二羟基硅氧烷。ACH化学和基于常规茂金属和MAO的茂金属催化剂体系的成功组合确保了H形LCB-PP的容易的、明确的、并且最重要的是高效的和高效的合成，与提供相同类型的LCB-PP的两种现有的优秀化学相比，包括ACH化学与非均相齐格勒-纳塔催化剂体系和非共轭α，研究了1，9-癸二烯和茂金属催化体系的ω-二烯烃共聚反应。
This paper reports a highly effective and efficient synthesis of long-chain-branched polypropylene (LCB-PP) rendered by combination ofω-alkenylmethyldichlorosilane copolymerization-hydrolysis (ACH) chemistry and metallocene catalyst system. The potential side reaction, the dichlorosilane-methylaluminoxane (MAO) double replacement reaction, is revealed to be slow-occurring and largely suppressible by slightly increasing the steric hindrance of the alkyl substituent(s) on the reactants. Thus, with 5-hexenylmethyldichlorosilane and 7-octenylmethyldichlorosilane of some increased alkenyl chain lengths, the main/side reaction competition dynamics inω-alkenylmethyldichlorosilane/propylene copolymerization with metallocene (rac-Me2Si-[2-Me-4-Ph(Ind)]2ZrCl2)-modified MAO complex involving the dichlorosilane-MAO double replacement reaction could shift disproportionally to the main copolymerization to the extent that the effect of the side reaction is not detectable. The synthesized LCB-PPs are characterized by narrow molecular weight distribution, with the LCB structure being H-shape and the interlinkage well defined as 1,2-dihydroxylsiloxane. The successful combination of ACH chemistry and metallocene catalyst system based on conventional metallocene and MAO assures a facile, well-defined, and, most importantly, highly effective and efficient synthesis of H-shape LCB-PP, as compared to two existing outstanding chemistries rendering the same type of LCB-PP, including ACH chemistry combined with heterogeneous Ziegler-Natta catalyst system and nonconjugatedα,ω-diolefin copolymerization (NDC) chemistry exercised with 1,9-decadiene and metallocene catalyst system.