Greatly improved toughness of isotactic polypropylene blends with traces of carbon nanotubes

Abstract

In this work, the β‐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 β‐nucleated iPP/POE blends with CNTs was as high as 51.7 kJ/m2, about 5.6 kJ/m2 higher than β‐nucleated iPP/POE blends, 15.2 kJ/m2 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 β‐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, β‐nucleating agent and POE on the toughness of iPP. POLYM. ENG. SCI., 59:757–764, 2019. © 2018 Society of Plastics Engineers