Crosslinking of Gelatin in the Reaction with Formaldehyde: An FT-IR Spectroscopic Study

The reaction of an aqueous solution of formaldehyde with gelatin dispersed in a potassium bromide pellet is monitored in real time by FT-IR spectroscopy. Principal component regression analysis of the spectra recorded at different times is carried out. On the whole, the latter results and the observed spectral changes are in agreement with a previously reported interpretation for the kinetics of the crosslinking reaction of gelatin with formaldehyde, according to which the reaction is initialized by the lysine–methylol formation and is subsequently followed by arginine–methylol, which, in turn, reacts with lysine–methylol to originate arginine–lysine crosslinks.