Thermally reversible cross-linked polyamides and thermo-responsive gels by means of Diels–Alder reaction

Cross-linked polyamides and polyamide gels were prepared from maleimide-containing polyamides and a tri-functional furan compound and showed thermal reversibility in cross-linking behavior and in gel formation through Diels–Alder (DA) and retro-DA reactions. The rate constant k of the DA cross-linking reaction were 1.25–4.83×10−5 dm3 mol−1 s−1 in the temperature range of 20–60 °C with an activation energy of 32.1 kJ mol−1. The cross-linking densities, thermal properties, and thermal reversibility of the polyamides/furan polymers were adjustable with the contents of maleimide groups in polyamides.