Morphological and impact properties of thermo-oxidative degraded polypropylene/metallocene linear low density polyethylene blend systems

Thermo- oxidative degradation of the blends of polypropylene ( PP) with metallocene linear low density polyethylene ( mLLDPE), has been examined. The samples were exposed in the air- oven for a period of 120 days at 150 degrees C. Scanning Electron Microscopy ( SEM) and Light Microscopy ( LM) were used for the study of morphology and the measurement of impact properties, to assess the embrittlement of the blend systems. In case of PP, surface cracks appeared spontaneously after 30 days of thermal aging. However, it has been observed that thermal stability of PP has significantly improved by blending it with mLLDPE even after 120 days of thermal aging. Similarly impact strength of PP has shown deterioration after 30 days while there is not much reduction in impact strength in case of PP/ mLLDPE blends. The presence of stabilizer in both materials has not shown much difference in impact strength and morphology. Therefore the stabilizer ratio can be optimized vis- a- vis appropriate PP/ mLLDPE blend composition.