Study On The Preparation Of Nanocrystal PVC And Its Application In The PVC/Nanometer CaCO₃ Composites

On the basis of survering of the relative literature, the mechanism and the present application of nanocomposite technologies in toughening and reinforcing PVC are detailedly introduced in this paper. It is inferred that fine PVC and nanometer CaCO3/PVC mixture are used to toughen and reinforce PVC.In this paper, the crystallinity of PVC modified by homemade nucleating agent is increased. The crystal PVC is crashed by jet-mill to prepare nanocrystal PVC. The crash, degradation and the change of morphology and crystalline structure changes of PVC is studied by FTIR, SEM, DSC, TEM. The self-plasticization of nanocrystal PVC is studied, too. The results show that there is anomalistic crystal whose size reaches nanometer grade in fine PVC; The crystal structure is damaged by jet-milling, which induces the melting point of nanocrystal PVC decreases from 210 to 128. The nanocrystal PVC induces the decrease of plasicizing time and equilibrium torque and the increase of maximal torque, which show that the nanocrystal PVC have self-plasticization in PVC composites.Nanocrystal PVC/PVC, nanocrystal PVC/PVC/nanometer CaC03 and nanocrystal PVC/PVC/light CaCO3 composites are prepared by mixing and pressing. The properties of these composites are studied in various content of nanocrystal PVC, light CaCO3 and nanometer CaCO3. The results show that the mechanical properties of nanocrystal PVC/PVC composite are increased, tensile strength increases from 43 MPa to 61.3 MPa, as well as impact strength from 47 kJ/m2 to 70.3 kJ/m2. The tensile strength and impact strength of nanocrystal PVC/PVC/nanometer CaCO3 composite both increase heavily, tensile strength increases from 43 MPa to 76.4MPa, as well as impact strength from 47 kJ/m2 to 100.9. kJ/m2. Nanometer CaCO3 is dispersed equably in nanocrystal PVC/PVC/nanometer CaCO3 composite by TEM test. The best content of nanometer CaCO3 is 10 part by weight(pbw); light CaCO3 have no ditinct toughening and reinforcing effect in nanocrystal PVC /PVC/light CaCO3 composite. Nanocrystal PVC promotes the form of claster crystal that induce the improvement of property of PVC by SEM test.Nanocrystal PVC and nanometer CaCO3 is applied in profile and tube .production. The properties of profile and tube are studied in various content of nanocrystal PVC and nanometer CaC03. The results show that nanocrystal PVC can instead ACR to improve the plasticizing property in processing and reduce cost; the mechanical and heat resistance of the profile and tube filled nanocrystal PVC and nanometer CaCO3 increase heavily.