| Summary: | 碩士 === 雲林科技大學 === 化學工程與材料工程研究所 === 98 === In this study, we use THF for the preparation of poly(methyl methacrylate) (PMMA)-intercalated organo-modified montmorillonite (OMMT), followed by treatments of supercritical carbon dioxide (sc CO2) and heat to investigate foam formations using wide angle X-ray diffractometer (WAXD), differential scanning calorimeter (DSC), and scanning electron microscope (SEM). The unmodified (NaMMT) and organic-modified montmorillonite (OMMT) clays are also comparatively studied. WAXD patterns find that PMMA is much less intercalated in NaMMT than in OMMT. Following sc CO2 treatments, the interlayer spacings of the PMMA/OMMT composites are reduced. At a given temperature, the interlayer spacing of the intercalated OMMT reduces with CO2 pressure, but at a given pressure, the interlayer spacing increases with temperature; this can be attributed to the closer solubility parameters for sc CO2 and PMMA so that PMMA is easier to be dragged out from the interlayers at higher pressures or lower temperatures. The sc CO2-treated samples can be found by WAXD to increase interlayer spacing with heat treatments, with the interlayer spacing of the intercalated OMMT increasing with temperature for a given treatment time but decreasing with treatment time for a given treatment temperature. DSC data find that the addition of OMMT causes a decrease in Tg of PMMA but this Tg would increase with increasing OMMT contents in the composites. SEM confirms the foam formation in the interlayer of OMMT.
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