| Summary: | 碩士 === 國立中興大學 === 材料工程學研究所 === 93 === Poly(lactic acid) has received considerable attention as a potential replacement for conventional polymer due to its biodegradability and favorable miscibility with other polymers. It is currently being investigated for biomedical application, pharmaceutical controlled release systems and in biodegradable packaging materials. However, the technological development of PLA in this area is limited by its poor thermal stability and mechanical properties. Thus several studies have been devoted to organic/inorganic nanocomposites with the aim to improve their properties.
In this study, we have used organically modified montmorillonite(MMT) as a dispersed phase to prepare the PLA/MMT nanocomposites. The fabricated PLA/MMT nanocomposites were then formed the PLA/MMT scaffolds using NaCl-leaching technique. Both X-ray diffraction data and TEM micrographs of PLA/MMT nanocomposites indicate most of the swelling silicate layer are exfoliated and randomly dispersed into PLA matrix. The PLA/MMT nanocomposites and scaffolds were found to be a bioactive material, as it formed calcium phosphate in the form of hydroxyapatite deposits in a simulated body fluid (SBF). The physical properties and biocompatibility of fabricated nanocomposites and scaffold can also be measured by DMA, GPC, FE-SEM, DSC and XRD.
From the results of FE-SEM after decomposition for 28 days, the porous structure of PLA/MMT nanocomposites and scaffolds were significantly destroyed and the results were consistent with the data of GPC. Interesting, the crystallization of PLA/MMT nanocomposites and scaffolds increase as increasing decomposition period indicating the better polymer chain arrangement after decomposition.
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