Biodegradation of Three-Layer Laminate Films Based on Gelatin Under Indoor Soil Conditions

J. F. MARTUCCI; R.A. RUSECKAITE

POLYMER DEGRADATION AND STABILITY

ELSEVIER

Año: 2009

0141-3910

Three-layer films composed by a 5wt.% sodium montmorillonite (MMt) - plasticized gelatin (Ge-5MMt) inner layer and dialdehyde starch (DAS) - crosslinked and plasticized gelatin (Ge-10DAS) outer layers obtained by heat-compression molding were submitted to degradation under indoor soil burial conditions for 14 days. Biodegradation of multilayer as well as individual components and control gelatin films was evaluated by monitoring water absorption and weight loss. It has been established that technological treatments performed on gelatin such as cross-linking, compounding with clay and heat-compression moulding have major impact on the biodegradation rate and extent. The possible reason was also discussed. Weight loss results revealed that the susceptibility to microbial attack during soil burial varied in the order: Ge-10DAS < multilayer < Ge-5MMt < gelatin control film. The intermediate behaviour of the multilayer was associated to the presence of hydrogen interactions between layers induced by processing. Scanning electronic microscopy revealed that multilayer was preferentially biodegraded by filamentous microorganisms and even larvae in the later stages of the process. The presence of holes and pits on the multilayer surface was more likely attributed to the preferential removal of glycerol and DAS as evidenced by thermo-gravimetric analysis.