Study On Preparative Technique And Properties Of PBT/OMMT Nanocomposites

Polymer/Layered silicate nanocomposites is composited by organic macromolecules that serve as continuous phase and lamellas of layered silicate that are at least in single dimension composited by nanoscale size (1-100nm). In recent years, experimental research and industrial exploitation of PLS nanocomposites were very active, but there were still many problems. In this research, PBT/OMMT nanocomposites were prepared through two different preparative methods which were monomer inserted—in-situ polymerization and melting intercalation by use of PBT and OMMT, and test results showed that its menchanical properties and flame retardant properties were better than pure PBT. Shandong province is rich in MMT resource and has many manufacture factories of PBT, the experimental study not only solves the deficiencies in properties of PBT and widens the field of application but also increases the added value of MMT. It is also the purpose and purport of the research.In the research, we used natural Ca-MMT as raw materials and prapared OMMT through purification of hign precision, cation exchange and organic modification. We discussed the influence of different modified methods and pH value on the modification of MMT. XRD results indicated that in subalkalic environment, long-chain organic cation-modifiers came up to the best results in the modification of MMT.PBT/OMMT nanocomposites were prepared by monomer inserted—in-situ polymerization and melting intercalation. The structure and interface features were characterized by XRD and SEM, and results showed that monomer inserted—in-situ polymerization and melting intercalation both made the long chains of PBT intercalate into the interlamination of OMMT and formed different types of nanocomposites(the former was intercalated-exfoliated structure; the latter was intercalated structure).The menchanical properties and flame retardant properties were characterized by electronic omnipotent testing machine, oxygenindex tester and so on. Results showed that only adding OMMT could improve both of the properties, but the flame retardant properties was not enhanced obviously. Coordination of OMMT and flame retardant played a synergy effect in the flame retarded properties which reached the standard (V-0 level), but the cost can be dropped by a wide margin. Through the comparison in study of two preparative methods, it was found that the structure and properties of PBT/OMMT nanocomposites prepared by monomer inserted—in-situ polymerization were better than those of melting intercalation, but its industrial craft was complex; Melting intercalation had advantages such as simpleness of procreative equipments, friendlyness in envrionment and easiness to continuous manufacture and so on, but the structure and properties of PBT/OMMT nanocomposites were a little less than those of monomer inserted—in-situ polymerization.We analysed the behaviour of crystallization and rheological behaviour of PBT/OMMT nanocomposites. It was found that OMMT played a part of nucleating agent which could enhance the crystallization rate and crystallinity of PBT. Enlarging the content of OMMT could enhance the viscosity of the system, but elevating the temperature and enhancing the rate of shear could lower the viscosity of the system. If the content of OMMT was too large, the flowability of system would turned out bad rapidly and it was to the disadvantage of contour maching.