Morphology, rheology and biodegradation of oxo-degradable polypropylene/polylactide blends

The blends of polypropylene (PP)/polylactide (PLA) with or without compatibilizer, and with pro-oxidant (cobalt stearate/calcium stearate) and pro-oxidant filled PP were prepared by using the melt blending technique. Films of these blends were prepared by compression molding. PP85PL15 and PP85PL15MA4 were the optimum blends from the tensile strength point of view. The improvement in the tensile strength of PP85PL15MA4 blend was achieved by addition of 4 phr compatibilizer. Cobalt stearate and calcium stearate were added separately to PP85PL15MA4 blend in 0.2% (w/w) ratio. The optimized blends were further characterized by differential scanning calorimetry, X-ray diffraction, rheological studies, scanning electron microscopy (SEM) and biodegradability test. Rheological studies confirmed the pseudo-plastic nature of all the blend samples. SEM studies have revealed that the addition of PLA in PP85PL15 enhances the void and roughness on the blend. All the prepared blends have biodegraded in the composting environment and the blend containing pro-oxidant biodegraded to the maximum extent.