| Summary: | 碩士 === 國立臺北科技大學 === 有機高分子研究所 === 100 === The aim to this study is to analysis tri-component copolymers of PET (Polyethylene Terephthalate). We added different percentage of AA (Adipic Acid) – 0 mole ratio (AA-1), 0.037 mole ratio (AA-2), 0.075 mole ratio (AA-3), and 0.117 mole ratio (AA-4) together with fixed amount of 0.009 mole ratio PEG (Polyethylene Glycol) to synthesis PET. To investigate their physical properties, we done series of tests on these tri-component copolymers.
Firstly we analysis from NMR spectrum and proved that the PET structures had grafted with PEG and AA. With GPC analysis, we known that PDI value is between 4 to 6. Using DSC and DMA to determine their Tm point, Tg point, and mechanical properties. We had found that by increasing AA percentage in the copolymer, their results were decreasing. By TGA, we had figured out the Td points were in the same temperature zone. We evaluated crystallinity with XRD, and we found that they had same direction with DSC (Tc). In AA-1 copolymer, we only added PEG and crystallinity was increased. By addition of AA, the crystallinity decreased.
Then, we analyses viscoelastic properties by Rheometer. The G’ and G” was decreased by the increase of temperature and AA additon. All the results were liquid-like behavior. During frequency of 10 rad/s, we evaluated difference of G’ value between 270° and 250°. We had found out with increasing of AA addition, the difference of G’ value were decreased. Furthermore, we used cole-cole plot method to test their compatibility. We had proved that PEG, AA, and PEG were incompatible materials.
Finally we used DSC to analysis isothermal crystallization. Operating by Avrami equation, we had ploted n value, k value and Tc point in DSC. The crystallization of DSC had same results with crystallization of XRD. From the result of half-time crystallization (t1/2) and crystallization rate (G1/2), we had known that by the increase of isothermal crystallization temperature, the t1/2 value decreased and the G1/2 value increased. The mechanism of PET/PEG/AA tri-component copolymers is a homogeneous nucleation.
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