Research Of Preparing Composite Calcium Carbonate Technology At High Temperature And Application

Ground calcium carbonate(GCC)has numerous applications in various areas of plastics,papers,rubbers,paints in order to reduce cost and improve properties.GCC is comminuted along the cleavage plane which cause it has flat surfaces and sharp edge angles.Flat surfaces limit contact area and coupling links between the polymer,and sharp edge angles cause many stress concentration points where breakage always initiate from in the polymer matrix.So let the smooth cleavage planes rough and the sharp edge angles blunt to improve the surface morphology of GCC,prepare high valueable composite calcium carbonate is quite necessary.In this article,we used intermittent sparging mixing carbonization method to prepare composite calcium carbonate.The technological parameter of the reaction system such as filling amount of GCC,concentration of Ca(OH)2,stirring intensity had significantly affect on composite calcium carbonate surface morphology.When added the appropiate crystal oriented agent at high temperature carbonization,prepared 50-80 nm globular nano-CaC03,the width about 50 nmlength-diameter ratio is about 3 of rodlike nano-CaCO3,the width about 30 nm length-diameter ratio is about 9 of needle-like nano-CaCO3 were respectively modified at surface of GCC,realized nano modification of GCC at high temperature.XRD analysis showed that composite calcium carbonate crystallizing stable calcite.Characterization of composite calcium carbonate found that specific surface area,whiteness,oil absorption value were higher than GCC,and also the fractal dimension,showed that after modification increase grain roughness.Ultrasonic disintegrator was employed to check the bond strength between the coating layer and GCC,and the result showed that it was a strong bond strength between them for the coating layer still existed without break after disintegrating by large power ultrasonic.Analysis carbonization process of preparing composite calcium carbonate,found that heterogeneous nucleation and homogenneous nucleation were existing in the reaction system.Composite calcium carbonate was filled into PP matrix to prepare composite polymer,and the experiment results showed that PP composites filled by composite calcium carbonate had better mechanical properties,could enhance the toughness of polymer materials.PP composites filled by composite calcium carbonate had better mechanical properties than that of GCC.The fracture morphology observed composite calcium carbonate had stronger bond with PP matrix than GCC.Composite calcium carbonate has good application potential in plastics,rubbers,paints and papers because of not only it can improve the polymer materials mechanical properties but also can reduce the cost of products.