Thermoplastic Superelastomers Based on Poly(isobutylene)-graft-Poly(l-lactide) Copolymers: Enhanced Thermal Stability, Tunable Tensile Strength, and Gas Barrier Property

• DOI: 10.1021/acs.macromol.9b02720
• Publication Date: 2020-04-01T16:35:55Z
• Authors: Jeong Suk Yuk; Eunbi Mo; Suhyun Kim; Haemin Jeong; Hyeonji Gwon; Nam-Kyun Kim; Young-Wun Kim; Jihoon Shin
• Keywords: Isobutylene; Thermoplastic elastomer; Oxygen permeability; Thermal Stability; Lactide

A mechanically adjustable reinforced thermoplastic superelastomer system, with tunable gas-permeability, was developed. The is based on a graft copolymer structure, using commercial butyl rubbers (or poly(isobutylene-co-isoprene), P(IB-co-I)) and l- or d,l-lactide (LLA LA) derived from renewable feedstocks, by "grafting from" controlled polymerization. First, hydroxyl-functionalized PIB (PIB-g-(OH)) macroinitiators were prepared through epoxidation an economical alternative to m-chloroperoxybenzoic acid ring-opening reaction. Second, PIB-based copolymers end-hydroxylated poly(lactide) as hard side-chains, PIB-g-(P(L)LA–OH)s, synthesized target fP(L)LA of 0.18–0.45, achieve mechanical reinforcement additional gas barrier. They subsequently acetylated acetic anhydride produce PIB-g-(P(L)LA–Ac)s improved thermal stability. well-defined molecular structures indicated P(L)LA lengths, the resulting superelastomers demonstrated stability increased Td,5%; microphase-separated having spherical and/or elongated features; behaviors proved TODT, which much lower than superior characterizations, proving control elastomeric-to-ductile properties. An oxygen permeability value low 27 mL mm m–2 day–1 atm–1 achieved increasing 0.45, comparable polyethylene terephthalate. partially biodegradable processable barrier films these PIB-g-PLLA have great potential for flexible packaging food medical products.