Study On The Surface Modification Of Calcium Carbonate And Its Applica-tion In PVC (Polyvinyl Chloride)

Polyvinyl-chloride (PVC) is one kind of general resins with low price and fine perfor-mances. But PVC must be toughening modification because of its poor processability and brittleness. Nano-CaCO3 is a common PVC toughening agent, but the compatibility between them is very bad, so the surface of nano-CaCO3 must be modified. Two kinds of modifiers are chose in this article to modify the surface of nano-CaCO3, then adding these particles to PVC and obtaining PVC composites.Firstly, we used octadecylamine, Dodecanamine and octylamine as representative of the aliphatic amine modifiers, and the nano-CaCO3 was modified by these modifiers. Then the PVC composites material was prepared. The influence of modified nano-CaCO3 on the me-chanical properties of PVC composites was studied. It was demonstrated that all of the modi-fiers could be combined with the surface of nano-CaCO3 very well, and the modified nano-CaCO3 can be dispersed in PVC resin evenly. The notched impact strength of the three kinds of PVC composites are dramatically increased, and the strength of composite modified by octadecylamine is 114 KJ/m2. Compared with PVC modified by pure nano-CaCO3(without modifier) and composite modified by coupling agent of organic titanic, the notched impact strength of composite modified by octadecylamine improve by 303.6% and 52%, respectively. The flexural strength of the PVC composites are slightly improved, but the tensile strength declined slightly.Secondly, three different modifiers were synthesized by the reaction of MA and Octade-canamine, Dodecanamine, Octylamine, respectively. The surface of nano-CaCO3 was treated in the same way by these modifiers and PVC composites were prepared. The influence of modified nano-CaCO3 with different modifiers on the mechanical properties of PVC compo-sites materials was investigated. It was found that these new modifiers also could be com-bined with the surface of nano-CaCO3 very well, and the modified nano-CaCO3 could be dis-persed in PVC well. Modified nano-CaCO3 by three kinds of modifiers could dramatically increase the impact strength of PVC, and the strength of composite modified by MDA is 96 KJ/m2. Compared with PVC modified by pure nano-CaCO3 and the composite modified by coupling agent of organic titanic, the notched impact strength of composite modified by MDA improve by 242.9% and 28%, respectively. Compared with aliphatic amine modifiers, the processing performance of the PVC composites modified by these new modifiers is greatly improved. It shows that two kinds of modifiers can improve toughening strength of PVC, but in the view of processing progress, the new modifiers are better choice.Finally, MSA, MDA were chose to modifier the nano-CaCO3, then changing the amount of nano-CaCO3 and CPE to optimize the production formulation. Studies show that when the content of MSA, MDAwas 3%wt and keeping content of nano-CaCO3 was 10 pigment con-centration, the content CPE can be controlled in 5-8 pigment concentration. Keeping the content of CPE is 10 pigment concentration, and the amount of nano-CaCO3 can be controlled in 10-15 pigment concentration. So we can optimize the production formulation by enhanc-ing the amount of nano-CaCO3 or reducing the content CPE.