Effect of Molecular Size of Modifying Agents on the Properties of Gelatin films

There is an increasing interest in developing renewable and degradable gelatin films for various applications. However, gelatin has to be modified before use due to its poor mechanical properties, sensitivity to water and microorganisms. In this work, gelatin films were modified physically and chemically. Effects of the molecular size of the modifying agents on the properties of the structure and properties of gelatin films were discussed. It was found that alcohols with higher molecular weight endowed the gelatin films with reduced migration ratio in water, showing an excellent plasticizing stability. Films chemically modified with macromolecule dialdehyde starch (DAS) showed obviously lower swelling ratio than that modified with small molecule glutaraldehyde (GTA). The present work indicated that the plasticizers and crosslinking agents with proper molecular size and molecular weight endowed the physically and chemically modified gelatin films with superior physical properties, providing useful information for the modification of gelatin and other biopolymers.