In-vitro degradation behaviour of starch/EVOH biomaterials

Blends of corn starch with poly(ethylene-vinyl alcohol) copolymer (SEVA-C) were aged up to 120 days on NaCl sterile isotonic solution (9 g/l) and the degradation solutions were analysed by several techniques. Mechanical prope rties (i.e. strength, stiffness and ductility), weight loss, and water upta ke were also assessed. The evolution of the material structure was followed by scanning electron microscopy (SEM), contact angle measurements and ther mogravimetric analysis (TGA). The degradation solutions were monitored with anionic chromatography (HPAE-PAD), colorimetric methods, and Fourier trans formed infra-red spectrophotomety (FT-IR) in order to quantify the amount o f plasticisers and sugars. SEVA-C micrographs presented an increase in the surface porosity as a function of immersion time. The main compound release d to the solution is glycerol, the other degradation products are low molec ular weight polymeric chains. From the physical-chemical point of view the material degradation is principally associated with the leaching of glycero l, since the other metabolites were not released. (C) 2001 Elsevier Science Ltd. All rights reserved.