Synthesis and healing properties of poly(arylether sulfone)–poly(alkylthioether) multiblock copolymers containing disulfide bonds

ABSTRACT Thermoplastic elastomers composed of soft and hard segments are important elastic and processable synthetic polymers. The microphase‐separated soft domains show low glass transition temperature and possess sufficient chain mobility at room temperature. In this study, we report the synthesis and healing properties of multiblock copolymers containing disulfide bonds as dynamic covalent bonds. The multiblock copolymers composed of poly(arylether sulfone) and poly(alkylthioether) segments were synthesized by oxidative coupling polymerization of the corresponding thiol‐terminated oligomers. Atomic force microscopy phase images, differential scanning calorimetry, and dynamic mechanical analysis curves indicated the microphase‐separated morphology of the multiblock copolymer. Self‐healing properties of the polymer were evaluated by changes in the elongation at break of the cut/adhered samples. The elongation recovery increased with UV irradiation time, and the multiblock copolymer showed a 93% recovery after UV irradiation for 5 h. The healing efficiency induced by UV irradiation, determined by subtracting the recovery without UV irradiation, was calculated to be 51%. According to the UV spectra and solubility changes after UV irradiation, the main healing factor in this study was the crosslinking reactions caused by thiyl radicals generated from UV irradiation instead of disulfide exchange reactions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3545–3553 Multiblock copolymers composed of hard (poly(arylether sulfone)) and soft (poly(alkylthioether)) segments were synthesized as new self‐healing thermoplastic elastomers via oxidative polymerization of thiol‐terminated oligomers. Self‐healing properties of the samples were evaluated by tensile tests of broken samples. Elongation at break of the broken sample after UV irradiation for five hours was recovered to 93% and the healing efficiency induced by UV irradiation was 51% against the elongation of uncut samples.