| Institution: | 1. Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 17, Hungary
Department of Plastics and Rubber Technology, Budapest University of Technology and Economics, H-1521 Budapest, P.O. Box 92, Hungary;2. Department of Physical Chemistry, Budapest University of Technology and Economics, H-1521 Budapest, P.O. Box 92, Hungary |
| Abstract: | The aggregation tendency of 11 different CaCO3 fillers with widely differing particle sizes was studied in polypropylene (PP) composites. The fillers were characterized by different techniques in powder form and in suspension. Homogenization and sample preparation were carried out by extrusion and injection molding, or in an internal mixer and compression molding, respectively. Thin slices were prepared from the composites and the relative area of aggregates was determined by image analysis. Tensile and fracture properties were studied as a function of filler content. The results proved that the extent of aggregation increases with decreasing particle size and increasing filler content. Surprisingly, extruded and injection molded samples contained more aggregates than those prepared by homogenization in an internal mixer followed by compression molding. Good agreement was found between the powder properties of the fillers and their performance in the composites. Deviations from the general tendency indicate that some factors, which were not accounted for in the study, also influence aggregation and composite properties. |
