Preparation and characterization of biodegradable trilayer films based on starch and polyester.

The trilayer films of polyester/starch/polyester with different starch/polyester layer thickness ratios were prepared by co-extrusion blowing. FTIR and SEM results showed the successful fabrication of trilayer films. The crystallinity of trilayer films gradually increased as the thickness of polyester layer increased. Dynamic mechanical analysis was used to investigate the compatibility between starch and polyester. The presence of polyester layer significantly increased the tensile strength and water contact angle of starch film. All trilayer films had lower water vapor permeability than the starch film, and lower oxygen permeability than the polyester film. The trilayer films were degraded to a much greater extent compared with the polyester film. The weight loss of P10 trilayer film in 120 days is about 80% through degradation test. These results suggested that the polyester/starch/polyester films with excellent mechanical and hydrophobic properties could serve as packaging material for wider applications.