Dramatically Accelerating II−I Crystal Phase Transition of Polybutene‑1 by In Situ Incorporation of H‐Shape Long‐Chain‐Branching Structures

Abstract

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 hours to even higher degrees.This article is protected by copyright. All rights reserved