Polymer / Montmorillonite Nanocomposites And Percolation Theory, Research,

Based on organophilic-modified-montmorillonite (O-MMT), polystyrene/ montmorillonite (PS/MMT) nanocomposites and polypropylene/montmorillonite (PP/MMT) nanocomposites were synthesized by intercalation polymerization in emulsion and polymer melted intercalation. Fourier Transition Infrared (FTIR) and X-ray Diffraction (XRD) characterization for composites' structure showed that, The chains of PS and PP have been intercalated into the galleries of MMT, and the position of the diffraction peak of MMT's 001 profile excursed to left (which means that the distance between layers has broadened) and the intensity of peaks has weakened. The diffraction peak of MMT's 001 profile has become a dispersed peak, which indicates an exfoliated state.In this thesis, the effects on nanocomposites' thermal properties caused by different O-MMTs and different contents of O-MMT have been studied. The result shows that the three kinds of Organic modified montmorillonites are all capable of improving the heat-resistant property. Comparatively speaking, the PS/O-MMT-3 composites exhibit best thermal properties. As for PS/MMT composites, the start temperature at thermal losing weight of composites that contains 8wt% MMT is highest. And as for PP/MMT composites, the thermal decomposition temperature firstly increases and then decreases with the contents of MMT increase In contrast to PP, the decomposition temperature of PP/MMT composites has improved 11 C when the content of MMT is 5 percent.The effects on nanocomposites' mechanical properties caused by different O-MMTs and different contents of O-MMT have been studied too. The results are as follows: as for PS/MMT composites, when the content of MMT equals 4wt%, the stretch strength reaches the highest value which has improved 34.3% compared with pure PP. For PP/O-MMT-1 composites, the stretch strength and the impact strength both exhibits a trend that firstly increases and then decreases with the contents of MMT increase. Also, the comprehensive properties when the content of MMT is 4 wt%. For instance, the stretch strength has improved 5.5% and the impact strength has improved 8.3% respectively.In this thesis, The Percolation Theory, a commonly applied theory in physical realm, has been applied to the field of polymer-based composites. The percolation models forvarious composites systems were offered. These models include the percolation model of iso-diameter particle filler random dispersed in polymers, the percolation model of different diameter particle filler random dispersed in polymers, the percolation model of plastics filled with fiberglass and the percolation model of plastics filled with layered silica. Moreover, the presumptions of various percolation models are proposed which give us a clew on the development of percolation theory and on the computer simulation of percolation model.The simulation program of the percolation model of iso-diameter particle filler random dispersed in polymer has been realized initiatorily, and its program algorithm has been elucidated.In this thesis, the percolation theory has been applied to qualitatively explain the changing trends of the properties of polymer/MMT nanocomposites studied by our group. At the same time, the program for the BDT percolation model of plastic composites filled with rubber, lodged by Qi Zong-neng, was programmed. The results of the running of the program agreed well with the reference. Furthermore, the program gives a visualized output of the BDT percolation model. Undoubtedly it provides references for further appliance of the percolation theory in the study field.