Microstructure and mechanical properties of isotactic polypropylene composite with two-scale reinforcement

Isotactic polypropylene (iPP) composite with two-scale reinforcement structure, i.e. nanoscale shish-kebab structure and micron-scale glass fiber (GF) with orientation, was fabricated by an oscillatory shear injection molding (OSIM) technology. The oscillatory shear flow provided by the OSIM gave rise to a high fraction of shish-kebab structures in the iPP composite, characterized by X-ray scattering technique. On the other hand, the oscillatory shear flow oriented GFs in the iPP composite, which was revealed by scanning electron microscopy measurement. The iPP composite with this two-scale reinforcement structure exhibited simultaneously remarkably enhanced tensile strength and impact strength. Fracture mechanism of this iPP composite was also proposed.