PREPARATION OF INDUSTRIAL MINERAL COMPOSITE POWDERS ANDTHE APPLICATION IN PP COMPOSITES

e mineral composite particles with rough surfaces and blunt edge angles , coated by nanometer calcium carbonate with a particle size range of 20～100 nm , were successfully prepared by a chemical method in Ca (OH)₂-H₂O-CO₂ system. The specific surface area of the composite powders increased twice or above after coating. It is exhibited thatpolypropylene (PP) composites filled by the composite powders with nano-structure surface have better properties becausethe nano-structured mineral powders have bigger surface areas which would lead to more interfacial compatibility betweenpowders and polymer matrix when the powders are filled into the polymer and moreover , the blunt edge angles would reduce the stress concentration at angles , compared with un-coated powders as filler.