Synthesis, spectral and thermal study of novel bisbenzoxazines based on cardo symmetric double Schiff bases

Abstract

This study presents synthesis of bisbenzoxazines (BBOC, BBOM, BBOS and BBOE) of symmetric double Schiff bases, by condensing 0.01 mol symmetric double Schiff bases, 0.04 mol formaldehyde, and 0.02 mol aniline. Bisbenzoxazines are thermally polymerized via ring-opening polymerization. Resultant cross-linked polymers (CBBOC, CBBOM, CBBOS and CBBOE) and bisbenzoxazines were characterized by solubility, IR, ¹H NMR, DSC and TGA. Bisbenoxazine ring transformation reaction occurs at high temperature as supported by exothermic DSC transition. Cured resins possess high thermal stability (257-425°C) and followed either single or multistep degradation kinetics.