In order to investigate the interfacial interaction in nano-CaCO3 /compatibilizer /polypropylene composites

three kinds of compatibilizers

polypropylene grafted with maleic anhydride(PP-g-MAH)

ethylene-octene copolymer grafted with maleic anhydride(POE-g-MAH) and ethylene-vinyl acetate copolymer grafted with maleic anhydride(EVA-g-MAH) with the same polar groups(MAH) but different backbones were used as compatibilizers.Nano-CaCO3 filled polypropylenes(PP /CC) modified by PP-g-MAH

POE-g-MAH and EVA-g-MAH were prepared by on a twin-screw extruder.In the compatibilized composites

the MAH polar groups of compatibilizers associated with the surface of nano-CaCO3 particles by polarity-polarity interaction

resulting in the formation of the core-shell structure in the composites and two interfaces were obtained: PP /compatibilizer interface and compatibilizer /CC interface.The effect of PP /compatibilizer and CC /compatibilizer interfaces on crystalline morphology

crystallization and melting behavior as well as mechanical properties of PP /CC was investigated by DSC

DMA

POM and WXRD.It was observed that the interfacial interaction between PP and CC in the PP /CC composites increased the crystallization temperature due to the heterogeneous nucleation of nano-CaCO3 particles

tensile modulus and impact strength of PP.In the compatibilized composites

the interfacial interaction between CC and compatibilizer further increased the crystallization temperature of PP.The chemical reaction between polar groups(MAH) of compatibilizer and nano-CaCO3 particles in this interface may lead to the formation of carboxylate salts with more heterogeneous nucleation.The carboxylate salts acted as a more effective nucleating agent further increases the crystallization temperature and crystallization rate of PP and induces the formation of β-crystal of PP.However

the heterogeneous nucleation of carboxylate salts was dependent on the interfacial interaction of PP /compatibilizer interface.The high compatibilization between PP and PP-g-MAH was favor to increase the heterogonous nucleation of carboxylate salts and tensile property of PP composites

but decrease the impact strength of PP / CC.The partial compatibility between PP and POE-g-MAH had little influence on the heterogonous nucleation of carboxylate salts and tensile property

but significantly increased the impact strength of PP /CC.However

poor compatibilization between PP and EVA-g-MAH retarded the heterogeneous nucleation of carboxylate salts and decreased the impact strength of PP /CC.