Polybenzoxazine precursors As self-healing agents for polysulfones

In this work, a novel self-healing system based on the use of polybenzoxazine precursor (PBP) as a healing additive is presented. PBP (M _n = 2300 g/mol, M_w/M_n = 2.6) is facilely synthesized in a reasonable yield by Mannich type polycondensation of bisphenol A, 1,6-diaminohexane with paraformaldehyde. The additive PBP faintly undergoes a thermal ring-opening reaction when contained in polysulfone (PSU) films. Thermal treatment at 160 C enables PBP to chemically bind to PSU chains and form networks through the Friedel-Crafts reaction, demonstrating a novel self-healing behavior. The extent of the recovery was studied using a stress-elongation (%) test and found to be 55%. Thermal properties of the polybenzoxazine precursor and the healed sample were investigated.