Fractal analysis of polypropylene composite filled with nano‐calcium carbonate

Polypropylene (PP) and nano‐calcium carbonate (CaCO 3 ) composites were prepared by melt mixing in a corotating twin‐screw extruder. Transmission electron microscopy study and particle size analysis revealed the dispersion and the size distribution of CaCO 3 in PP. With the increase of loading of filler, CaCO 3 nanoparticles densely aggregated together and the dispersion of filler became bad. The fractal dimensions of the composites were determined using fractal concept. The fractal dimensions of D and D k described the irregularities of the shape of an object and the distributions of particle populations, respectively. The D and D k values were influenced by the content of filler, i.e., the D values increased, and the D k values decreased with the increase of loading of filler. When the loading of filler was low, the values of D and D k of PP composites differ slightly than the counterparts of PP/PP‐ g ‐MA (50 wt %) blend. For 20 wt %, they were almost identical. This fact showed that the fractal dimension was correlated with the dispersion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008