Crystallization behavior of polypropylene filled with surface‐modified calcium carbonate

Polypropylene (PP) and calcium carbonate (CaCO 3 ) were mixed in a two‐roll mill. The mixed compounds were molded on the plate by using a compression press heater. To improve the affinity of the relation between CaCO 3 and the PP matrix, we modified the CaCO 3 surface through chemical reaction with alkyl dihydrogen phosphates. The CaCO 3 content and size modification affected the crystallization behavior of the filled PP composites. The crystallization temperature in the nonisothermal crystallization process increased with the increase of CaCO 3 content and the decrease of CaCO 3 size. The crystallization temperature revealed the function of log (1 + T s ) ( T s , total surface area of CaCO 3 ) irrespective of CaCO 3 content and size for modified and unmodified systems, respectively. The shoulder or double crystallization peak of PP composites is recognized for the unmodified system (particle sizes: 1.0 and 4.5 μm).