Applications of FT-IR spectroscopy to the studies of esterification and crosslinking of cellulose by polycarboxylic acids: Part I. Formation of cyclic anhydrides as the reactive intermediates

Butanetetracarboxylic acid (BTCA) has been the most effective nonformaldehyde crosslinking agents for cotton cellulose. In this research, we applied FT-IR spectroscopy in combination with thermalgravimetry (TG) and differential scanning calorimetry (DSC) to investigate the formation of carboxylic anhydrides by BTCA in its pure form and as a finish on cotton fabric. The FT-IR spectroscopy and TG/DSC data indicated that BTCA is converted to anhydride when the temperature reaches the vicinity of its melting point. The formation of the anhydride is accelerated above the melting point. The FT-IR spectroscopy data also showed that BTCA forms an anhydride at much lower temperatures when it is applied to cotton fabric as a finish.