Effect of interfacial interaction on the crystallization and mechanical properties of PP/nano‐CaCO 3 composites modified by compatibilizers

To investigate the effect of interfacial interaction on the crystallization and mechanical properties of polypropylene (PP)/nano‐CaCO 3 composites, three kinds of compatibilizers [PP grafted with maleic anhydride (PP‐ g ‐MA), ethylene–octene copolymer grafted with MA (POE‐ g ‐MA), and ethylene–vinyl acetate copolymer grafted with MA (EVA‐ g ‐MA)] with the same polar groups (MA) but different backbones were used as compatibilizers to obtain various interfacial interactions among nano‐CaCO 3 , compatibilizer, and PP. The results indicated that compatibilizers encapsulated nano‐CaCO 3 particles, forming a core–shell structure, and two interfaces were obtained in the compatibilized composites: interface between PP and compatibilizer and interface between compatibilizer and nano‐CaCO 3 particles. The crystallization and mechanical properties of PP/nano‐CaCO 3 composites were dependent on the interfacial interactions of these two interfaces, especially the interfacial interaction between PP and compatibilizer. The good compatibility between PP chain in PP‐ g ‐MA and PP matrix improved the dispersion of nano‐CaCO 3 particles, favored the nucleation effect of nano‐CaCO 3 , increased the tensile strength and modulus, but reduced the ductility and impact strength of composites. The partial compatibility between POE in POE‐ g ‐MA and PP matrix had little effect on crystallization and mechanical properties of PP/nano‐CaCO 3 composites. The poor compatibility between EVA in EVA‐ g ‐MA and PP matrix retarded the nucleation effect of nano‐CaCO 3 , and reduced the tensile strength, modulus, and impact strength. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009