Phosphate-based covalent adaptable networks with recyclability and flame retardancy from bioresources

Abstract Epoxy thermosets play a significant role in our life, while they have three common issues of depending on fossil resources, flammability and recycle difficulty. Nowadays, it’s still a challenge to address them simultaneously. Here, we report phosphate-based epoxy covalent adaptable networks (CANs) with reprocessability, degradability and flame retardancy from bioresources. Epoxy monomer synthesized from itaconic acid was cross-linked with phytic acid to achieve the phosphate-based epoxy CANs. The CANs were reprocessed at 160 °C within 1.5 h with the activation energy of the bond exchange of 49–90 kJ mol−1 and were readily degraded under mild basic conditions. Meanwhile, the epoxy CANs presented flame retardancy with UL-94 V0 rating and high LOI of 31.2–33.5% on account of the high phosphorus content of phytic acid. This work opens the door of developing phosphate-based CANs and provides a simple method to produce bio-based and fire-safe thermosets.