α,ω-Epoxide, Oxetane, and Dithiocarbonate Telechelic Copolyolefins: Access by Ring-Opening Metathesis/Cross-Metathesis Polymerization (ROMP/CM) of Cycloolefins in the Presence of Functional Symmetric Chain-Transfer Agents.

Elise Vanbiervliet,Guillaume Michaud,Stéphane Fouquay,Frédéric Simon,Sophie M Guillaume,Jean-François Carpentier

doi:10.3390/polym10111241

Abstract

Epoxide- and oxetane-α,ω-telechelic (co)polyolefins have been successfully synthesized by the tandem ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclic olefins using Grubbs’ second-generation catalyst (G2) in the presence of a bifunctional symmetric alkene epoxide- or oxetane-functionalized chain-transfer agent (CTA). From cyclooctene (COE), trans,trans,cis-1,5,9-cyclododecatriene (CDT), norbornene (NB), and methyl 5-norbornene-2-carboxylate (NBCOOMe), with bis(oxiran-2-ylmethyl) maleate (CTA 1), bis(oxetane-2-ylmethyl) maleate (CTA 2), or bis(oxetane-2-ylmethyl) (E)-hex-3-enedioate (CTA 3), well-defined α,ω-di(epoxide or oxetane) telechelic PCOEs, P(COE-co-NB or -NBCOOMe)s, and P(NB-co-CDT)s were isolated under mild operating conditions (40 or 60 °C, 24 h). The oxetane CTA 3 and the epoxide CTA 1 were revealed to be significantly more efficient in the CM step than CTA 2, which apparently inhibits the reaction. Quantitative dithiocarbonatation (CS2/LiBr, 40 °C, THF) of an α,ω-di(epoxide) telechelic P(NB-co-CDT) afforded a convenient approach to the analogous α,ω-bis(dithiocarbonate) telechelic P(NB-co-CDT). The nature of the end-capping function of the epoxide/oxetane/dithiocarbonate telechelic P(NB-co-CDT)s did not impact their thermal signature, as measured by DSC. These copolymers also displayed a low viscosity liquid-like behavior and a shear thinning rheological behavior.

Highlights

Telechelic polymers, i.e., polymers with functional end-groups, attract much interest due to their unique properties
Both oxetane- and epoxide-functional chain-transfer agent (CTA) have been developed in order to access the corresponding α,ω-difunctional coPOs (Scheme 1)
While the bis(oxiran-2-ylmethyl) maleate CTA 1 was prepared according to the previously reported procedure [44], the two oxetane functional CTAs were prepared by sequential transesterification reactions

Summary

Introduction

Telechelic polymers, i.e., polymers with functional end-groups, attract much interest due to their unique properties. They are commonly used as precursors to block copolymers, as cross-linking agents, or as intermediates in the formation of polymeric networks [1,2,3,4]. Telechelic POs are valued synthetic targets with major uses that are derived from their adhesion, toughness, print/paintability, compatibility with diverse, more polar materials, and rheological properties. Efforts both in academia and in industry are, currently dedicated to developing such polymer materials. While post-polymerization chemical modification enables us to incorporate the desired functions at the termini of POs, metathesis polymerizations have been revealed to be a most useful and effective direct approach towards α,ω-functional POs [5,6,7,8,9,10,11,12,13]

Methods

Results

Conclusion