Graphene Nanosheets and Shear Flow Induced Crystallization in Isotactic Polypropylene Nanocomposites

By Jia-zhuang Xu, Cheng Chen, Yan Wang, Hu Tang, Zhong‐Ming Li, Benjamin S. Hsiao. 2011

174 citations recorded by the source corpus.

Combined effects of graphene nanosheets (GNSs) and shear flow on the crystallization behavior of isotactic polypropylene (iPP) were investigated by in-situ synchrotron wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) techniques. For crystallization under quiescent condition (at 145 °C), the half-crystallization time (t1/2) of nanocomposites containing 0.05 and 0.1 wt % GNSs was reduced to at least 50% compared to that of neat iPP, indicating the high nucleation ability of GNSs. The crystallization rate of iPP was directly proportional to the GNS content. Under a relatively weak shear flow (at a rate of 20 s−1 for 5 s duration) and a low degree of supercooling, the neat iPP exhibited an isotropic structure due to the relaxation of row nuclei. However, visible antisotropic crystals appeared in sheared iPP/GNSs nanocomposites, indicating that GNSs induced a network structure hindering the mobility of iPP chains and allowing the survival of oriented row nuclei for a long period of t...

Subfields: Biomaterials, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/9002cd9cf7df8cee5e0b81ce85151589287d0d2b