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.
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http://dx.doi.org/10.1016/j.ijbiomac.2024.129363 | DOI Listing |
RSC Adv
January 2025
Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya Aichi Japan 466-8555
We recently proposed a concept of self-transformation from thermoplastic polyesters into vitrimers intermolecular bond exchange as the cross-linking reaction. Key was the use of polyesters bearing hydroxyl side groups, which were cross-linked without additional cross-linkers through intermolecular transesterification in the presence of a suitable catalyst. In our previous study, a linear polyester was synthesized as the starting polymer by reacting dithiol monomers containing ester bonds (2-SH) with diepoxy monomers (2-epoxy) a thiol-epoxy reaction, generating hydroxyl side groups along the polyester chain.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), CONICET/UNMdP, Av. Colón 10850, B7606BWV, Mar del Plata, Argentina.
This study addresses the extension of the service life of carbon-fiber reinforced epoxies by inducing thermal healing of microcracks through the use of a vitrimer as a polymeric matrix. Our aim was to explore the feasibility of using a blend of selected carboxylic acids (citric, glutaric, and sebacic acids) and commercial monomers to design a matrix specifically developed for technological implementation in composites with the ability of intrinsic repair of microcracks under moderate (even remote) heating treatments. The selection of the formulation (the acid blend, catalysts, and monomers) was the result of an exhaustive prescreening analysis of processing requisites and final properties.
View Article and Find Full Text PDFMater Horiz
December 2024
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
Glass fiber reinforced polymer (GFRP) composites are valued for their strength and cost-effectiveness. However, traditional GFRPs often face challenges for end-of-life recycling due to their non-depolymerizable thermoset matrices, and long-term performance due to inadequate interfacial adhesion, which can lead to fiber-matrix delamination. Here, we have designed dynamic fiber-matrix interfaces to allow tough and closed-loop recyclable GFRPs by utilizing a vitrimer, derived from upcycled polystyrene--poly(ethylene--butylene)--polystyrene (SEBS) with boronic ester (S-Bpin) and amine-based diol crosslinker.
View Article and Find Full Text PDFPolymers (Basel)
November 2024
Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
Introducing dynamic ester bonds into epoxy-anhydride resins enhances the reprocessability of the crosslinked network, facilitated by various types of transesterification catalysts. However, existing catalysts, such as metal salts and organic molecules, often struggle with dispersion, volatility, or structural instability issues. Here, we propose to solve such problems by incorporating a liquid-state, thermally stable transesterification catalyst into epoxy resins.
View Article and Find Full Text PDFPolymers (Basel)
November 2024
Department of Aerospace Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Nowadays, self-healing materials have been studied actively in electronics, soft robotics, aerospace, and automobiles because they can prolong the life span of the materials. However, overcoming the trade-off relationship between mechanical properties and self-healing performance is challenging. Herein, graphene oxide-polyaniline (GO-PANI) filler was introduced to overcome this challenge because GO has a highly excellent modulus, and nitrogen atoms in PANI can endow a self-healing ability through hydrogen bonds.
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