Self-Healing Catechol-Based Polybenzoxazine Vitrimers Containing Disulfide Bonds

A series of catechol-based polybenzoxazine (PCT) vitrimers with self-healing and triple shape memory properties were prepared by using 4-aminophenyl disulfide (APDS) as a curing agent. A biobased main-chain type benzoxazine precursor (CT-appdms) was synthesized from catechol, aminopropyl-terminated poly(dimethylsiloxane) (APPDMS), and paraformaldehyde. Then, a series of polybenzoxazines containing dynamic disulfide bonds were prepared by using different amounts of APDS. Due to the introduction of disulfide bonds, the PCT vitrimers had dynamic exchange activation energies between 47.8 and 58.2 kJ/mol. The dynamic exchange of disulfide bonds and the flexible poly(dimethylsiloxane) segments endowed PCT with self-healing and triple shape memory properties. The self-healing efficiencies of the vitrimers for the first healing increased from 57 to 88% in terms of tensile strength with the increased amounts of APDS. In addition, the PCT vitrimers exhibited high hydrophobic properties with static water contact angles above 105°. This work provides a feasible route for the preparation of self-healing polybenzoxazine vitrimers.