Crosslinking of Gelatin with Formaldehyde; a 13C NMR Study

Abstract

The different species formed when gaseous formaldehyde is dissolved in aqueous medium are investigated by a 13C NMR flow-through technique and the spectra of commercial aqueous form­aldehyde solutions containing methanol completely interpreted. 13CH2O was used to study the crosslinking reaction with gelatin which leads to methylene and oxymethylene bridges between gelatin-amino-groups. On ageing, hardened gelatin shows an increase in the number of methylene bridges.