| Irradiation induced intermolecular cross-linking of polymers, silane-grafted water-crosslinked polymers and the polymer/clay nanocomposites are the important techniques for the modification of polymers. However, based on the investigation of a large amount of literatures, it is founded that articles on the influence of irradiation on the structure and properties of polymer/clay nanocomposites and the study on silane-grafted polymer based nanocomposites are lacking. In this dissertation, the polyethylene/organophilic montmorillonite nanocomposites (PE/OMT) modified by gamma-ray irradiation and silane-grafted water-crosslinking techniques were studied systematically. Meanwhile, in order to improve the flame retardant and mechanical properties of PE, the inorganic whisker-magnesium hydroxide sulfate hydrate whisker (MHSH) reinforced and flame retardant polyethylene composites were also investigated. The morphology and performances of the above mentioned materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transfer infrared (FTIR) spectroscopy, thermogravimetric analyses (TGA), cone calorimetry and so on. The main conclusions are as followings:1. Study on the influence of gamma irradiation on polyethylene/clay nanocomposites:1.1 The dispersion of the clay in the exfoliated maleic grafted polyethylene (MAPE)/ organo-montmorillonite (OMT) nanocomposites evolved under gamma-ray irradiation. TEM images demonstrated that the morphology of the nanocomposite evolved via three stages under irradiation: ideally face-face ordered exfoliation, followed by a completed disordered dispersion of stacked layers, and relative ordered distribution of stacked layers. Three facts are postulated to be responsible for the evolution: the first is the interaction of clay layers, the second is the formation of the new conformation at polymer-clay interface and the last is the...
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