Bio-based epoxy vitrimer with inherent excellent flame retardance and recyclability via molecular design

• Published in: International journal of biological macromolecules Vol. 262; no. Pt 1; p. 129363
• Main Authors: Zhou, Mei-Hui, Ao, Xiang, Islam, Monsur, Liu, Yu-Yao, Prolongo, Silvia González, Wang, De-Yi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-03-2024
• Subjects: Bio-epoxy vitrimer; Epoxy Resins; Ethers; Ethyl Ethers; Flame Retardants; Imines; Intrinsic flame retardancy; Recyclability; Bio-epoxy vitrimer; Recyclability; Intrinsic flame retardancy
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.129363

The development of biobased fire-safe thermosets with recyclability heralds the switch for a transition towards a circular economy. In this framework, we introduced a novel high-performance bio-epoxy vitrimer (named GVD), which was fabricated by forming a crosslinking network between bio-epoxy glycerol triglycidyl ether (Gte), varying amounts of reactive flame-retardant agent 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) (0–7 wt%) and a vanillin-based hardener (VA) with imine bonds. For instance, the epoxy vitrimer GVD5, featuring a DOPO content of 5 wt%, achieved a V-0 rating in the vertical burning test (UL-94) and obtained a limiting oxygen index (LOI) value of 31 %, surpassing the performance of pristine epoxy. Furthermore, the peak heat release rate and total heat release of GVD5 were reduced by 38.2 % and 26.3 %, respectively, compared to pristine epoxy. The GVD vitrimers further demonstrated exceptional reprocessability and recyclability, attributed to the presence of dynamic imine bonds within the topological crosslinking network. Remarkably, the epoxy vitrimers maintained the mechanical properties of the parent epoxy. Therefore, this work provides a facile strategy for fabricating high-performance and multi-functional bio-epoxy thermosets.
[Display omitted]
•Bio-epoxy vitrimer exhibits excellent flame retardancy via introducing 5 wt% DOPO.•Bio-epoxy vitrimer imparts excellent reprocessability and recyclability.•Bio-epoxy vitrimer possesses good mechanical strength via reprocessing procedures.•Flame-retardant mechanisms of epoxy were attributed to both condense and gas phases.