Crystallization behavior of polypropylene filled with surface‐modified calcium carbonate

Polypropylene (PP) and calcium carbonate (CaCO3) 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 CaCO3 and the PP matrix, we modified the CaCO3 surface through chemical reaction with alkyl dihydrogen phosphates. The CaCO3 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 CaCO3 content and the decrease of CaCO3 size. The crystallization temperature revealed the function of log (1 + Ts) (Ts, total surface area of CaCO3) irrespective of CaCO3 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).