Acoustic Microscopy Evaluation of Polypropylene/Calcium carbonate Composites.

Dispersion behavior has been characterized by acoustic microscopy method for polypropylene (PP) filled with calcium carbonate (CaCO3). The heterogeneous structure of the large size such as aggre gate, agglomerate of the filled particles and presumably void at polymer-particle interface possessing mod ulus heterogeneity in the compounds were evaluated. Binarization method was carried out in order to obtain area fraction of the structure. The relationship between dispersion behavior and content, size and surface treatment of the filler, and the mechanical property (elongation at break) has been investigated. The heter ogeneous structure was inclined to increase with the increase in CaCO3 content and the decrease in CaCO3 particle size. The heterogeneous structure in composites filled with CaCO3 of various particle sizes marked ly decreased by the surface treatment of CaCO3. While, the elongation at break of PP/CaCO3 composites could roughly be expressed as a function of aggregation or agglomeration fraction calculated from ultra-sonic image.