Preparation of thiolated polyvinyl alcohol hydrogels

The esterification reaction of polyvinyl alcohol (PVA) with thioglycolic acid (TGA) in the presence of sulfuric acid as a catalyst offers an attractive route to develop thiolated functional material. During esterification maximum thiol content of 3.9 mmol/g was achieved. It was observed that the esterification is significantly influenced by the reaction conditions, such as TGA concentration, reaction time, reaction temperature and reactant concentration. Sulfuric acid had considerable influence on the thiolation. The thiol content was found to increase with the reaction temperature but showed significant increase beyond 60 degrees C. The swelling decreases with the increasing reaction temperature indicating the role of crosslinking during the thiolation at higher temperature. Suitable conditions for the modification of PVA via thiolation have been investigated. The involvment of thiol group in the PVA matrix was confirmed by ATR-FTIR spectra. The micro analysis of sulfur in sample by EDX analysis showed the sulphur content of 3.7%. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 129: 815-821, 2013