Polyisobutylene Stars and Polyisobutylene-block-Poly(tert-Butyl Methacrylate) Block Copolymers by Site Transformation of Thiophene End-Capped Polyisobutylene Chain Ends

Abstract

A new synthetic route for the synthesis of polyisobutylene (PIB) stars and PIB-poly-(methacrylate) block copolymers was developed by combining living carbocationic and anionic polymerizations. Rapid and quantitative monoaddition of thiophene to living PIB chains has been observed in conjunction with TiCl 4 as Lewis acid in n-hexane/CH2Cl2 60/40 v/v at -78 °C leading to the formation of 2-polyisobutylenyl-thiophene (PIB-T). PIB-T was quantitatively metalated with n-butyllithium in THF at -40 °C. 1 H NMR spectroscopic and GC studies of the corresponding model compound, 2-(1,1,3,3tetramethylbutyl)thiophene, clearly verified quantitative metalation. The resulting stable macrocarbanion (PIB-T -,Li + ) was used to initiate living anionic polymerization of tert-butyl methacrylate (tBMA) yielding PIB-b-PtBMA block copolymers with high blocking efficiency. PIB stars were prepared via the coupling reaction of the stable macrocarbanion with SiCl4 as a coupling agent. Characterization of these block copolymers and PIB stars was carried out by size exclusion chromatography (SEC), liquid adsorption chromatography at critical conditions (LACCC), and NMR spectroscopy.

Polymeric Surfactants: Synthesis, Properties, and Links to Applications

“…Thiophene has been found to be a suitable capping agent, which is more successful compared to furan (known to lead to unwanted secondary reactions). 159 Reaction of thiophene-terminated PIB with n-BuLi provides an efficient macroinitiator for anionic polymerization of tBMA. The polyisobutylene hydrophobic block is usually synthesized by a cationic procedure using BCl 3 /TiCl 4 catalyst.…”

Synthesis and Characterization of Poly(methyl methacrylate‐co‐hydroxyethyl methacrylate)‐b‐polyisobutylene‐b‐poly(methyl methacrylate‐co‐hydroxyethyl Methacrylate) Triblock Copolymers

“…For instance, Müller et al reported the synthesis of PIB-b-poly( t butyl methacrylate) (P t BMA) and poly(methyl methacrylate) (PMMA)-b-PIB-b-PMMA by metalation of DPE end-capped PIB with Na/K alloy or cesium followed by anionic polymerization (3,4). Another attempt demonstrated by Müller et al involved the preparation of thiophene end-functionalized PIB and subsequent metalation of the polymer chain end with an alkyllithium compound, followed by polymerization of t BMA with the generated macroanion (5). In a recent publication, we also reported the synthesis of PIB-b-PMMA by a novel coupling approach combining living cationic and anionic polymerization techniques (6).…”

Structural characterization of telechelic polyisobutylene diol

“…The same THF/methanol 80.5/19.5 (w/w) composition has already been employed by Mueller and coworkers for the LCCC analysis of PIB block copolymers. [26] However, this solvent composition is not suitable for high MW PIB as suggested by the very low sample recovery observed with M n = 20900 due to precipitation of the polymer.…”