CAS Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Macromol Rapid Commun. 2024 Aug;45(16):e2400195. doi: 10.1002/marc.202400195. Epub 2024 May 11.
This communication reports an effective strategy helping address the long-troubling melt processing issue of isotactic polybutene-1 (i-PB) caused by its extremely slow II-I crystal phase transition. The solution lies in a facile synthesis of i-PB containing H-shape long-chain-branching structures (LCB-i-PB) by applying a so-called ω-alkenylmethyldichlorosilane copolymerization-hydrolysis (ACH) chemistry to butene-1 polymerization with Ziegler-Natta or metallocene catalysts. It is evident that the H-shape LCB structures effectively enhance chain entanglements of i-PB and induce an over-the-board acceleration of the overall melt crystallization process including nucleation, form II crystallization, and form II-form I phase transition. As i-PB usually requires up to a week to reach equilibrium of the II-I phase transition, it is found that with LCB-i-PB such a transition is almost finished within as short as 24 h to even higher degrees.
本通讯报道了一种有效的策略，有助于解决等规聚丁烯-1（i-PB）长期存在的熔融加工问题，该问题由其极其缓慢的 II-I 晶相转变引起。该解决方案在于通过应用所谓的ω-烯基甲基二氯硅烷共聚-水解（ACH）化学，在齐格勒-纳塔或茂金属催化剂存在下使丁烯-1聚合，从而制备出含有 H 形长链支化结构（LCB-i-PB）的 i-PB。显然，H 形 LCB 结构有效地增强了 i-PB 的链缠结，并促使整个熔融结晶过程（包括成核、形成 II 型结晶和 II 型- I 型相转变）全面加速。由于 i-PB 通常需要长达一周的时间才能达到 II-I 相转变的平衡，因此发现，使用 LCB-i-PB，这种转变几乎在 24 小时内甚至更高程度内完成。
