Abstract: A three layer films composed of poly(propylene carbonate)(PPC) and poly(butylene adipatecobutylene terephthalate)(PBAT) having excelled barrier and mechanical properties were prepared bycoextrusion multilayer. The effect ofthe thickness of PPC layer, PBAT layer, anddifferent traction speed at a constant extrusion output on properties of PBAT/PPC/PBAT films was investigated. The results showed that the tensile strength and the processibility of PBAT/PPC/PBAT films were improved in comparison with PPC films. The maximum of the tensile strength was increased by about 200 %. Thickness of the films and molecular chain orientation degree has great effect on barrier behavior of the composite films. At a maximal PPC layer thickness of about 12 μm, oxygen permeation is the lowest, 9.5×10^-15 cm3·cm/(cm2·s·Pa). At the highest traction speed, that is,the molecule chain orientation degree is the maximum, oxygen permeation is the lowest, 9.52×10^-15 cm3·cm/(cm2·s·Pa).

Key words: poly(propylene carbonate), poly(butylene adipate-co-butylene terephthalate), multi-layer co-extruded film, fully biodegradablability, barrier