Study On The Surface Modification Of Calcium Carbonate And Its Application To PVC

To improve the dispersion and compatibility of nano-CaCO₃in PVC （polyvinyl chloride） matrix and the interfacial interaction between the nano-CaCO₃and PVC.Through molecular design new modifiers PAMs was successfully prepared and was used in the surface modifi-cation of nano-CaCO₃. The application of PAMs-CaCO₃to toughen the PVC matrix was studied in this paper.In chapter2, PAMs were synthesized respectively by single esterification with the phthalic anhydride and butyl alcohol, octanol, cetyl alcohol, diethylene glycol monobutyl ether.Wet modification was used to treat the surface of nano-calcium carbonate which was then added into PVC matrix to study the properties of PVC. Through FT-IR, SEM, TEM, impact strength, tensile and other tests we can conclude that among these modifiers PAD was the best. In chapter3,the modifier PAD was used in the surface modification of nano-CaC03.The best conditions of wet modification and the change of the surface of nano-CaCO₃was investigated through the Sedimentation volume,Contact angle and oil-absorption value tests.In chapter4, PVC/CaCO₃nanocomposites added with PAD-CaCO₃were prepared to study the mechanical properities of and morphology of PVC nanocomposites which repectively added with different modifiers,different contents of PAD and PAD-CaCO₃nanoparticles.The comprehen-sive properities of PVC/CaCO₃were also investigated through the impact strength, flexure modulus and the tensile strength test.The results show that with the modification of four different modifiers, the surfaces of nano-CaCO₃changed from hydrophile to hydrophobe and PAD was the best modifider.The dispersion of CaCO₃in PVC matrix and the processing properties were improved after the surface modification of CaCO₃.The presence of PAD-CaCO₃led to slight decrease in the tensile strength and flexible strength but sharp increase in fracture toughness.