Effect of stretching speed on morphologies and properties of in situ microfibrillar POE/PLA composites

In situ microfibrillar ethylene-octene copolymer (POE)/poly(lactic acid) (PLA) composites (MFCs) with different phase morphologies were prepared by controlling the stretching speed and maintaining the weight ratio of POE/PLA of 80/20. Four different stretching speeds were employed to study the effect of PLA microfibrillar morphology on tensile, crystalline, and rheological properties of MFCs. Scanning electron microscopic images revealed that the morphology of PLA phase was strongly influenced by stretching speed. MFCs with highest aspect ratio and smaller diameter of PLA microfibrils were obtained with a stretching speed of 60 rpm. The PLA microfibrils with high aspect ratio had the best reinforcement effect on MFCs. The dynamic rheological properties indicated that the MFCs achieved higher storage modulus and loss modulus at the stretching speed of 60 rpm.