Greatly Improved Toughness of Isotactic Polypropylene Blends With Traces of Carbon Nanotubes

In this work, the [beta]-nucleated isotactic polypropylene (iPP)/ ethylene-octene copolymer (POE) blends demonstrated greatly enhanced impact toughness by adding traces of carbon nanotubes (CNTs) (only 0.05 wt%). When the POE content was 30 wt%, the impact strength of [beta]-nucleated iPP/POE blends with CNTs was as high as 51.7 kJ/[m.sup.2], about 5.6 kJ/[m.sup.2] higher than [beta]-nucleated iPP/POE blends, 15.2 kJ/[m.sup.2] higher than CNTs-filled iPP/POE blends, and almost 19 times of pure iPP sample. This significantly improved impact toughness was considered to be attributed to the shear yielding and multiple-crazing, originating from the presence of abundant [beta]-crystals in the iPP matrix, the enhanced mobility of the molecular chains in the confined amorphous region of iPP lamellae and the homogenous distribution of POE dispersed phase with a small size, indicating the synergistic effect of CNTs, [beta]-nucleating agent and POE on the toughness of iPP.
INTRODUCTION As a general plastic, isotactic polypropylene (iPP) is widely used in our daily life from common packaging and textile products to components in cutting-edge automobiles and aircraft, due to [...]