Because thermosets have superior thermal stability, mechanical properties, and chemical resistance relative to common thermal plastics, thermosets are widely used in many areas for coatings, construction, and aerospace. However, poor reusability of thermosets remains a challenge, resulting in considerable plastic pollution. A new class of polymeric materials, termed vitrimer, were proposed to solve this problem and have drawn greater attention. Vitrimers are covalent adaptive crosslinked networks, in which the crosslinks undergo swift dynamic exchange and rapid topology change. The dynamic properties of vitrimers enable macroscopic flow and good reprocessibility. Herein, we report a poly(methyl methacrylate) (PMMA) based vitrimer-like material. The materials were synthesized from PMMA with hydroxyethyl methacrylate and aromatic disulfide crosslinkers. Incorporating aromatic disulfide crosslinks greatly improved the solvent resistance, dimensional stability, and mechanical properties of PMMA without sacrificing its transparency and thermal stability. Additionally, the dynamic exchange reaction of the aromatic disulfide afforded the rapid stress relaxation, and thus the PMMA vitrimer could be reprocessed efficiently and repeatedly. The reprocessed PMMA vitrimer showed comparable mechanical properties to the original material. The total performance of the aromatic disulfide crosslinked PMMA will lead to potential applications in 3D printing.

Fully reprocessable vitrimer-like materials based upon aromatic disulfide linkages

ACS Spring 2022

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