Properties of Gelatin Gum-Arabic Coacervates Composited With Amino Resins

Only a small percent of the formaldehyde added to the coacervation solution is actually utilized for crosslinking the gelatin and gum arabic in the dense coacervate phase, the rest remaining in the colloid-poor solution. It was aimed to use this formaldehyde in the solution in a polymerization reaction with urea to form a composite film of gelatin-gum arabic coacervate within a supramolecular structure of the urea-formaldehyde resin. Part of the urea added reacts with formaldehyde used for crosslinking, opening up the polymer chains, and part reacts with free formaldehyde to form urea-formaldehyde resin phase grafted onto the coacervated macromolecules. The physical properties of the composite film investigated in this work, i.e. water absorbance, water vapor sorption and permeability, are interpreted as a function of the structure evolving as a result of the competing crosslinking and polymerization reactions.