No abstract

Endowing epoxy resin with high performance, controllable degradation as well as feasible upcycling is a huge challenge. Herein, we synthesized a bio-based amine curing agent containing spiro diacetal unit using an environment-friendly method, then the controllable degradable epoxy resin was obtained after the curing reaction between diamine (DVPM) and bisphenol A epoxy resin (DGEBA). Results showed that DVPM-DGEBA resin performed high glass translation temperature of 136 C, glassy storage modulus of 3.93 GPa, and tensile strength of 85.9 MPa, owing to spiro diacetal unit and abundant methoxyl-related hydrogen bonds confirmed by non-isothermal fourier transform infrared spectra (FT-IR) and dynamic mechanical analyses. More importantly, DVPM-DGEBA resin could decompose into soluble linear oligomers in mild acidic solution. Systematically investigated by 1 H nuclear magnetic resonance, gel permeation chromatography, and FT-IR. Furthermore, the recycled oligomers could be reprocessed into thermosetting resins in the presence of diamines, and the upcycling resin performed high-performance (glass translation temperature of 170 C, glassy storage modulus of 6.03 GPa and tensile strength of 86.4 MPa) and flame-retardant (V-0 rating). This work gives us some new ideas to achieve the upcycling of the thermoset resin.