Cationic Copolymerization of Isobutylene with 4-Vinylbenzenecyclobutylene: Characteristics and Mechanisms.

Zhifei Chen,Shan Huang,Shuxin Li,Yibo Wu,Yuwei Shang,Wenli Guo,Kangda Wu

doi:10.3390/polym12010201

Abstract

A random copolymer of isobutylene (IB) and 4-vinylbenzenecyclobutylene (4-VBCB) was synthesized by cationic polymerization at −80 °C using 2-chloro-2,4,4-trimethylpentane (TMPCl) as initiator. The laws of copolymerization were investigated by changing the feed quantities of 4-VBCB. The molecular weight of the copolymer decreased, and its molecular weight distribution (MWD) increased with increasing 4-VBCB content. We proposed a possible copolymerization mechanism behind the increase in the chain transfer reaction to 4-VBCB with increasing of feed quantities of 4-VBCB. The thermal properties of the copolymers were studied by solid-phase heating and crosslinking. After crosslinking, the decomposition and glass transition temperatures (Tg) of the copolymer increased, the network structure that formed did not break when reheated, and the mechanical properties remarkably improved.

Highlights

Over the years, isobutylene (IB) has played a crucial role in cationic polymerization due to its special structure
We studied thermal and mechanical properties through the solid-phase crosslinking of poly(IB-co-4-VBCB)
Wereactivity first added IB Scheme to the initiation to avoid the of self-polymerization of 4-VBCB

Summary

Introduction

Isobutylene (IB) has played a crucial role in cationic polymerization due to its special structure. Copolymers with different structures and functions are obtained by the copolymerization of IB and other monomers [12,13,14,15,16]. Obtaining a functionalized copolymer by introducing a specific monomer during IB polymerization is an important research direction. The BCB’s strained four-membered ring opens when heated to >180 ◦ C to form a high-activity intermediate, o-quinodimethane. Benzocyclobutene (BCB) and its derivatives are attracting considerable attention because of their special thermal properties. This intermediate can react with dienophiles through the Diels–Alder reaction, thereby forming a six-membered ring

Methods

Results

Conclusion