In order to investigate the influence of β-phase on the mechanical properties of CaCO
3
/polypropylene (CaCO
3
/PP) composites
β-PP composites were prepared by PP filled with the mixture of nano CaCO
3
(CC) supported with β-nucleating agent (β-CC) and CC or micro CaCO
3
(WC). Using PP-g-MA
POE-g-MA and EVA-g-MA as compatibilizers
the compatibilized composites were also prepared. The results indicated that the tensile strength of PP composites decreased and tensile modulus increased with increasing the content of CaCO
3
. Addition of β-CC increased tensile modulus of PP and had no influence on the tensile strength of PP. Compatibilization of PP-g-MA increased the tensile strength
tensile modulus and impact strength of filled PP composites. Compatibilization of POE-g-MA significantly increased the impact strength of filled PP composites. Compatibilization of EVA-g-MA decreased the tensile properties of filled PP composites. The impact strength of β-CC/PP composites increased with increasing the content of β-CC and the impact strength of β-CC/CC/PP and β-CC/WC/PP were higher than those of CC/PP(w(CC)/w(PP)=5/95) and WC/PP(w(WC)/w(PP)=5/95)