writer：Wentao Wang, Juan Zhang, Feng Jiang, Xuehui Wang*, and Zhigang Wang*
keywords：glass transition, mechanical property, microphase separation, noncovalent, RAFT polymerization, supramolecular network
source：期刊
specific source：ACS Appl. Polym. Mater., 2019, 1, 571-583
Issue time：2019年

A new strategy was proposed to enhance tensile strength, toughness, and extensibility of BAB-type reprocessable supramolecular triblock copolymer elastomers (STBCPEs) by simply incorporating 1-vinylimidazole (VI) as a minor comonomer to introduce metal–ligand coordinate bonds of minor contents into the soft matrix. Poly(n-butyl acrylate-co-1-vinylimidazole)-b-poly(isobornyl acrylate)-b-poly(n-butyl acrylate-co-1-vinylimidazole) (P(BA-co-VI)-b-PIBA-b-P(BA-co-VI)) triblock copolymers with varied molecular masses were synthesized via successive reversible addition–fragmentation chain transfer (RAFT) polymerization. Zinc chloride (ZnCl₂) was used to coordinate with the pendent imidazole groups in the soft matrix. These supramolecular STBCPEs exhibited simultaneously improved creep-resistance, Young’s modulus, tensile strength, and toughness without sacrificing any extensibility. Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) results indicated that these supramolecular elastomers showed typical microphase-separated morphology. The microstructure of elastomeric STBCPEs consisted of microphase-separated glassy PIBA domains, serving as physical cross-linking points for one network, and metal–ligand cross-linked clusters formed by ZnCl₂ and imidazole groups, which constrained the soft flexible end P(BA-co-VI) blocks, serving as cross-linking points for the second network. This strategy provides a novel means to design high-performance reprocessable supramolecular elastomers through strategically introducing a network of dynamic metal–ligand interaction into the microphase-separated thermoplastic elastomeric system.

https://pubs.acs.org.ccindex.cn/doi/abs/10.1021/acsapm.8b00277