Nature of the Carbonyl Groups in Oxidized Polyvinyl Alcohol and Its Degradation

Abstract

In the previous report we found that oxidized PVA degraded through a reverse aldol reaction when it was treated by alkaline solution, but that only one third of the carbonyl groups of the PVA contributed to the degradation. The reason became clear in the present study. The carbonyl groups of the PVA undergo keto-enol tautomerism depending on pH and temperature and may assume acidic behavior in some conditions. When the PVA is treated in strong acidic solution, all the carbonyl groups take keto-form and contoribute perfectly to the degradation reaction.