Efficient synthesis of main chain thermosetting polybenzoxazine resin containing tert-butylcyclohexanone and diphenylmethane units for supercapacitor energy storage

Ring-opening polymerization (ROP) can synthesize polybenzoxazine (PBZ) precursors from their respective benzoxazine monomers, resulting in thermosetting phenolic resins. In this study, we synthesized DADCA-DADPM BZ using 4-(tert-butyl)-2,6-bis((E)-4-hydroxybenzalidene)cyclohexan-1-one (DADCA) and 4,4′-diamino-diphenylmethane (DADPM) with paraformaldehyde. The resulting DADCA-DADPM BZ and poly(DADCA-DADPM BZ)_X materials were obtained after thermal curing polymerization at temperatures ranging from 110 to 250 °C were employed as electroactive materials in electrode preparation for supercapacitors (SCs). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed a thermal curing temperature of 230 °C, a char yield of 35 wt%, and a decomposition temperature (T_d10) of 288 °C. The electroactive material DADCA-DADPM BZ and poly(DADCA-DADPM BZ)_X materials were evaluated for their suitability in SCs, showing a specific capacitance ranging from 84.6 to 166.6 F g⁻¹, depending on the thermal curing temperature (110–250 °C). Notably, the poly(DADCA-DADPM BZ)_250 retained 60% of its capacitance efficiency after 5000 cycles at current density of 10 A g⁻¹, highlighting its potential for recyclability.