Influence of Biodegradable Poly(butylene carbonate) on Plasticized Polylactide Blown Films

ABSTRACT The polylactide (PLA) was blended with poly(1,2‐propylene glycol adipate) (PPA) and poly(butylene carbonate) (PBC). Then the extruded PLA/PPA/PBC blends were processed in the form of blown films. All of the ingredients used in the films are biodegradable. The miscibility, fracture surface morphology, and rheological properties of the PLA/PPA/PBC blends, further thermal properties, the tear‐fracture surface morphology, crystalline morphology, and mechanical and optical properties of the blown films were investigated. PPA did not enhance the miscibility between PLA and PBC. From SEM micrographs of the cryogenically fracture surfaces, PBC particles evenly dispersed in the PLA matrix. It could increase the nucleating density of the spherulites and decrease the size of the spherulites of PLA. The results indicated that the 85.5/9.5/5 PLA/PPA/PBC film had excellent tensile strength, elongation at break, tear strength, and transmittancy. The shear yielding induced by cavitation of PBC particles was the major tearing mechanism during the film tear test. The enzymatic degradation of PLA was slightly retarded in the presence of both PPA and PBC. These findings contribute new knowledge to the additives area and give important implications for manufacturing biodegradable polymer packaging materials.