Comparative kinetics of induced radical autocondensation of polyflavonoid tannins. I. Modified and nonmodified tannins

Comparative kinetics of the radical autocondensation induced by SiO2 of a polyflavonoid tannin, namely quebracho tannin a mostly profisetinidin/prorobinetinidin tannin, in its natural extract state, sulfited, carbohydrate free, and in its adhesive intermediate form were carried out by electron spin resonance (ESR). The results obtained not only confirmed the existence of strong radical mechanisms of tannin autocondensation in the presence of...