| Summary: | 碩士 === 中原大學 === 化學研究所 === 96 === Abstract
Clays are considered to be the ideal reinforcement additives for advanced polymer composites because of their excellent improvement in the mechanical strength, electronic and thermal properties. Poly (ethylene terephthalate) (PET)/clay nanocomposites have been prepared by in-situ polymerization in vacuum system. The morphologies of Poly (ethylene terephthalate) (PET)/clay nanocomposites were investigated by wide angle X-rays diffraction (WAXD) and transmission electron microscopy (TEM) techniques which indicate that the nanocomposites were mostly intercalated and partially exfoliated. Thermo-gravimetric analyzer (TGA), dynamic mechanical analyzer (DMA) and differential scanning calorimeter (DSC) were applied to study the thermal and mechanical properties. The gas (oxygen, nitrogen and carbon dioxide) barrier property was measured by gas permeability analyzer (GPA) which confirms that the better dispersion of clay in the polymer matrices provides much higher gas barrier property. Optical property was measured by UV-Vis spectra which shows the materials are good optical clarity.
PET belongs to highly crystalline polymer; therefore we may use variable temperature XRD to observe the change of crystallinity. In 120C ~ 200C temperature range, it has been observed that the crystallinity is increased compared to pure PET with increasing the concentration of clay into the PET polymer. In this work, two types of clays, CL-88 and CL-120 with CEC of 200 and 168 meq of 100 g of clay; respectively, are applied as inorganic layered materials. Two clays are modified with different modifier to increase the compatibility between polymer and clay, followed by preparation of PET/clay nanocomposites. The properties of all nanocomposites are compared with respect to thermal, mechanical and gas barrier properties.
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