Development of reprocessable novel sulfur-containing epoxy based on thermal treatment

Inspired by the Diels–Alder reaction (DA reaction), the product of the reaction of 2-thiophenecarboxaldehyde (TCD) with epichlorohydrin (ECH) was combined with 1,4-anthraquinone to form a DA structure (a sulfur-containing self-healing epoxy resin (EP-DA) containing a large amount of π-electrons) was synthesized. The chemical structure, thermal properties, thermo-reversibility and tribological properties of EP-DA were studied by FTIR, DSC, gel–sol conversion and MRH-3G, respectively. The results indicated that the as-prepared epoxy composite network, which contains the thermally reversible D–A bond, enabled the epoxy resin to undergo self-repair. Moreover, the waste epoxy resin can be recycled and reused. The friction and wear of the epoxy during actual use were simulated. Macroscopic qualitative observation and quantitative measurement of shearing and peeling recovery were combined to examine the repair behavior and reprocessing ability of EP-DA, confirming that this material has good performance of self-repair and reprocessability, with the highest repair efficiency of up to 83.4%. Moreover, the introduced sulfur-containing diene body greatly improved the lubricating performance of the material, and the treatment time of waste reprocessing had a great influence on the content of the sulfur-containing epoxy monomer in the final EP-DA film. It was often possible to determine the degree of recovery of frictional properties. Inspired by the D–A reaction, a self-assembled large molecule that shares a large number of π-electrons is constructed.