| Summary: | 碩士 === 逢甲大學 === 纖維與複合材料學系 === 100 === In this study, a new type of resin cyclic butylene terephthalate(CBT) have low viscosity and low processing temperature. The PBT/pCBT composites made by the PBT plain weave and PET plain weave with CBT by hot press processing respectively. Besides, the CBT also combined with PET/pCBT to form the self-reinforcement composites, then compared with pure resin(PBT). On the other hand, the PET fiber of this study is the same as former research, due to this reason, the PET self-reinforcement also compared in this study. In this experiment, part of sample were processed by the annealing treatment, and observing the mechanical properties. From the results, the toughness of self-reinforcement have obviously increased after the plain reinforcement compared with pure resin.(PBT) It did not have any crack even reach to the limit of test machine. PBT/pCBT composites and PET/pCBT self-reinforcement composites with fabric reinforcement was 4.7 times and 18 times compared with pure resin(PBT) respectively. The result of annealing processed show that annealing process would make the material have re-crystallization phenomenon, and the PET/pCBT self-reinforcement increased 21% and 80% in flexural strength and flexural modulus after the annealing processed. Annealing treatment would bring the higher crystallization so that the impact property decreased 18%. Besides, due to the PBT fiber have poor heat resistance and bring the thermal cracking, resulting in decreased the mechanical properties, therefore PBT fiber system is not adopt for annealing process.
PCBT not only breaking the traditional shortcoming of high viscosity of thermoplastic resin, but also go through the obstacle of fiber reinforced thermoplastic, when it was introduced to the market. In recent research many authors study on the properties of pCBT, but only on the first heating. Due to the awareness of environment and recycle, the mechanical of recycle was more important than before. In this study, two kind of system situ crystalline after polymerization and situ polymerization and crystallinity would be research. The crystal morphology of pCBT Reprocessed has been observed after second heating, also analysis the relationship between the district of Hoffman-Weeks and the transition temperature. Besides, the experiment also produced pCBT/carbon fiber composite and reused of pCBT/carbon fiber composite, then observing the effect of crystallization morphology, degree of polymerization, degree of crystallization and the border of crystallization on mechanical properties. From the PLM results, the district of transition temperature is the same as the actual crystal type. At the high temperature and long time, the crystallization is larger and the border is more short, the impurity are easier for gather up so that the break would happed earlier. At the fast cooling down, the fast emerge of small crystallization would cover the impurity before they gather up, and due to the small crystallization have longer border, the growth of crack need longer path can through the material, so that the system have better mechanical properties.
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