Vitrimers are a new class of materials that simultaneously offer the physical properties of thermosets at working temperatures and malleability/reprocessability of thermoplastics at processing temperatures. This vitrimer behavior is imparted by their dynamic cross-links that can shuffle bonds at elevated temperatures. In this study, we develop a new strategy for vitrimer design via direct silyl ether metathesis reaction. Specifically, we synthesized cross-linked poly(ethylene-co-vinyl alcohol) (PEOH) via dynamic silyl ether linkages. First, pendant hydroxyl groups on PEOH are capped with trimethylsilyl (TMS) moieties, which protect the alcohol from detrimental side reactions such as oxidation and dehydration. Next, vitrimers were prepared by crosslinking the TMS functionalized PEOH with a difunctional silane crosslinker in presence of a Lewis acid catalyst. Networks were generated with gel fractions &gt;90% while still maintaining reprocessability. The vitrimer properties such as recyclability and stress relaxation at various temperatures were carefully investigated. This work demonstrates a universal method to convert commercially relevant alcohol-bearing polymers to vitrimers.

New vitrimer design via direct silyl ether metathesis reaction

2019 Fall National Meeting

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