A fully bio-based epoxy vitrimer: Self-healing, triple-shape memory and reprocessing triggered by dynamic covalent bond exchange

TLDR

Vitrimers are a new class of polymers with promising applications in innovative materials. The study aims to overcome the challenge of producing plant‑oil based vitrimers that combine high glass‑transition temperatures and mechanical strength. The authors employ epoxidized soybean oil, rich in epoxy groups, and demonstrate that transesterification reactions modify the network structure as evidenced by stress‑relaxation measurements. They synthesize a fully bio‑based ESO‑FPA vitrimer with a Tg of 65 °C and tensile strength of 16 MPa that self‑heals, exhibits triple‑shape memory, and can be reprocessed through dynamic covalent bond exchange, thereby broadening the utility of commercial ESO.

Abstract

Vitrimers are a new type of polymers with promising applications in innovative materials. Epoxidized soybean oil (ESO) is an ideal candidate for vitrimer preparation owing to its abundant epoxy groups. However, preparing plant oil-based vitrimers with high glass transition temperatures (Tg) and strength remains challenging. A novel and fully bio-based vitrimer with a Tg above room temperature was synthesized from ESO and a rosin derivative-fumaropimaric acid (FPA) and exhibited excellent self-healing, shape memory, and reprocessing due to the presence of dynamic covalent bond exchange. The fully bio-based ESO-FPA vitrimer exhibited a Tg of 65 °C and a tensile strength of 16 MPa, which resulted from the rigid structure and tricarboxylic groups of FPA. The effect of transesterification reactions on the network structure was confirmed through stress relaxation. Our work expands the applications of commercial ESO in vitrimer materials and provides a novel approach to prepare bio-based vitrimers with desirable properties.