| Summary: | 碩士 === 國立臺北科技大學 === 分子科學與工程系有機高分子碩士班 === 107 === This study used various instruments to analyze and identify the properties and crystallization behavior of a series of Polybutylene terephthalate/Polytetramethylene Ether Glycol thermoplastic Polyester Elastomer (TPEE) synthesized in this laboratory. The first part is the identification of components and properties. Firstly, the results of PBT and PTMEG copolymerization were confirmed by FTIR and NMR spectroscopy. The actual peak ratio of PTMEG in each material was calculated from the corresponding characteristic peak area of NMR spectrum. When the Tg point was tested by DMA, it was found that the Tg point decreased significantly with the increase of PTMEG content. The same trend appeared when the Tm test by DSC. Indicating that the softness of the whole molecular chain was obtained with the increase of the soft chain PTMEG content And the Tm and Tg decrease. However, there was no significant difference between pure PBT and other copolymers at the Td test (5%) by TGA, indicating that the initial cracking step was dominated by the hard segment PBT. The second part is non-isothermal crystallization kinetics. The temperature is raised and lowered by DSC at 2, 5, 10, 20 °C/min. The crystallization curve is observed. It is found that under the same cooling condition, when the proportion of PTMEG increases, the temperature range of the crystallization peak was lowered. And then analyzed and compared using the Avrami and Mo models, and the crystallization activation energy was calculated by the Kissinger equation. The third part is a temperature-controlled hot plate with a polarizing microscope to make the materials isothermally crystallize and observe the behavior and crystallization rate changes. Similar to the DSC non-isothermal crystallization, at the same temperature, the crystal growth rate decreases as the PTMEG content increases. The crystal morphology, with the increase of PTMEG content, the more obvious the color of negative spherulite field. Indicating that the soft segment increases the flexibility of the molecular chain, and the stack is more regular. In the same material, as the crystallization temperature increases, the molecular chain kinetic energy is enhanced and it is difficult to form a stack, the color different becomes inconspicuous, and the shape of the crystal deviates from the spherical shape.
|
|---|
