Long-chain polyester dicarboxylic acid-induced rapid transesterification chemistry of biobased epoxy system for improved self-repairing performances

Constructing self-repairing epoxy materials based on transesterification chemistry can be regarded as a potential path for practical industrial applications given on its simplicity and ease of processing. However, there is still a challenge to improve the slow bonding exchange process for desired healing performances. Herein, this work reports a simple and effective strategy to prepare high-biomass-content self-repairing epoxy materials by introducing polyester oligomer (PEO) dicarboxylic acid as modifier into epoxidized soybean oil and itaconic acid compounds. The PEO is synthesized from glutaric anhydride and 1,4-cyclohexanediol, as well possess a unique pentamer molecular structure. It not only endows the epoxy system with improved molecular mobility in virtue of its long-chain structure, but also increases the number the essential ester groups of transesterification process, thus synergistically promoting bonding exchange rate for expected properties. As a result, the employment of PEO decreases the activation energy from 100 to 70 KJ/mol, as well as presents optimized self-repairing efficiency in storage modulus and tensile strength tests compared to the control group. It may provide a new and practical way to fabricate high-effective self-repairing epoxy system for industrial applications.