Ternary nano-CaCO3/poly(ethylene terephthalate) fiber/polypropylene composites: Increased impact strength and reinforcing mechanism

The binary nano-CaCO₃/polypropylene (PP), poly(ethylene terephthalate) (PET) fibers/PP and ternary nano-CaCO₃/PET fibers/polypropylene composites were prepared by melt blending method, and their structure and mechanical properties were investigated. The results show that the ternary nano-CaCO₃/PET fibers/PP composite displays significantly enhanced mechanical properties compared with the binary PET fibers/PP and nano-CaCO₃/PP composites, and neat PP. The X-ray diffraction, dynamic mechanical analysis, scanning electron microscopy and analysis of the non-isothermal crystallization kinetics were used to investigate the reinforcement mechanism of composites. The results indicate that the interfacial action and compatibility between PET fiber and PP are obviously enhanced by the addition of modified nano-CaCO₃ particles in the ternary composites and the mechanical property enhancement in the ternary system may be mainly originated from the formation of β-form crystallites of PP induced by the synergistic effect between PET fibers and nano-CaCO_3.