Catalyst-free gallic acid-based epoxy vitrimers with reprocessability and high glass transition temperature

• Published in: Polymer (Guilford) Vol. 311; p. 127462
• Main Authors: Yao, Yucheng, Cao, Zhaolin, Huang, Nengkun, Yu, Min, Tan, Jihuai, Zhu, Xinbao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 09-10-2024
• Subjects: Bio-based vitrimers; Catalyst-free; Gallic acid; High glass transition temperature; Reuse; Stress relaxation; High glass transition temperature; Stress relaxation; Gallic acid; Catalyst-free; Bio-based vitrimers; Reuse
• ISSN: 0032-3861
• DOI: 10.1016/j.polymer.2024.127462

General approaches for preparing epoxy vitrimers required lots of catalysts to accelerate transesterification to form the cross-linked network and the residual catalyst not only resulted in toxicity but also poor compatibility with other components. Herein, a green and facile strategy for preparing gallic acid epoxy resin (GA-EP) was developed under catalyst-free condition using renewable gallic acid, xylitol and hexahydro 4-methylphthalic anhydride (MHHPA) as feedstocks. The results indicated that the bio-based epoxy vitrimer had higher glass transition temperature (122 °C), satisfactory mechanical, thermal and degradation properties compared to neat Bisphenol A-based epoxy vitrimer. Furthermore, recycled GA-EP was ground into powder and added to the fresh resin to investigate its reusability. Compared to the original, the recycled epoxy vitrimer system demonstrated comparable performance, except for minor reductions in glass transition temperature (Tg) and modulus, likely stemming from the inherent inhomogeneity of the reprocessed material. This work provides a new approach to the production of high Tg bio-based epoxy vitrimers without adding any catalyst.
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•Vitrimers based on gallic acid are utilitarian materials and prime contenders for industrial applications.•The glass transition temperature of the vitrimers was controlled by the addition of polyol (xylitol).•Gallic acid-derived catalyst-free epoxy vitrimers exhibit high Tg (122.3–182.8 °C) and recyclability.