Polyisobutylenes with Controlled Molecular Weight and Chain-End Structure: Synthesis and Actual Applications

Abstract

The polymerization of isobutylene allows us to obtain a wide spectrum of polyisobutylenes (PIBs) which differ in their molecular weight characteristics and the chemical structure of chain-end groups. The bulk of the PIBs manufactured worldwide are highly reactive polyisobutylenes (HRPIBs) with –C(Me)=CH2 end-groups and low-molecular weights (Mn < 5 kDa). HRPIBs are feedstocks that are in high demand in the manufacturing of additives for fuels and oils, adhesives, detergents, and other fine chemicals. In addition, HRPIBs and CMe2Cl-terminated PIBs are intensively studied with the aim of finding biomedical applications and for the purpose of developing new materials. Both chain control (molecular weight and dispersity) and chemoselectivity (formation of exo-olefinic or –CMe2Cl groups) should be achieved during polymerization. This review highlights the fundamental issues in the mechanisms of isobutylene polymerization and PIB analysis, examines actual catalytic approaches to PIBs, and describes recent studies on the functionalization and applications of HRPIBs and halogen-terminated PIBs.

A Bio-Based Tackifier Synthesized by Room-Temperature Cationic Copolymerization of Isobutene and β-Pinene

“…Moreover, selectivity in the initiation as well as termination reaction, along with β-proton abstraction in the polymerization using an aluminum halide-based catalyst system, which is widely applied for industrial manufacturing, is vigorously studied [22,23]. The addition of dialkyl ether enabled the yielding of low molecular weight polyisobutene, with vinylidene end groups over 90 mol% [24][25][26][27][28][29][30]. The main characteristic of this catalyst system is that the operation temperature is relatively high (−30~20 • C).…”