Enhanced Mechanical Recycling of Polymer Mixtures by a Trifunctional Dynamic Crosslinker.

Westworth, Xavier; Shamsan, Essa; Gao, Yunpeng; Carr, Nevaya; Chen, Eugene Y-X · Adv Mater · 2026

basic_science · Level V

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Abstract

Mechanical recycling of mixed post-consumer apolar/polar polymers, due to their mis-matched polarity and inherent immiscibility, is typically a downcycling process yielding brittle materials. An emerging method that can enhance recycling of such mixtures into dynamically crosslinked, high-performance thermosets is a dynamic crosslinker (DC) platform; however, current DCs typically require an external catalyst and, due to their insufficiently high peak activation temperature (T<sub>a</sub> <190°C), are limited to a subset of applicable polymers and unsuitable for industrial melt-extrusion processing of high melting temperature (T<sub>m</sub>) polymers. Herein, we report a trifunctional DC incorporating three sought-after properties: thermally robust pyridotriazole cores as the high-T<sub>a</sub> (245°C) crosslinking sites compatible with reactive extrusion up to 270°C; dynamic siloxane linkages as the robust yet exchangeable bonds; and pyridine/ester functionalities as the internal catalysis sites devoid of external catalysts. Overall, this self-catalyzed, high-T<sub>a</sub> DC can compatibilize waste plastic mixtures containing high T<sub>m</sub> polymers and impart the recycled mixtures with superior thermoset properties such as enhanced creep resistance and thermomechanical stability while being melt-(re)processable.