| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 103 === Polyacrylonitrile (PAN) is a common precursor for manufacturing carbon fiber in industrial production. In this study, the effects of initial spinning condition and heat treatment temperature (HTT) on the structures and mechanical properties of PAN precursor fiber and the corresponding carbon fiber were investigated. Moreover, the hereditary effect of precursor fiber, oxidized fiber and the subsequent carbon fiber was evaluated by WAXS, DSC, TGA, FTIR, SEM, EA and tensile test. The PAN precursor fiber was successfully produced through wet spinning method by an industrial spinning line at Industrial Technology Research Institute (ITRI) of Taiwan. From the 2D WAXS patterns and tensile test, it was found that the higher draw ratio and DMSO content in the initial spinning condition produce stronger precursor fiber due to the enhancement in crystal orientation. However, the mechanical properties possessed by the precursor fiber with better initial spinning condition cannot be translated into the resulting carbon fiber. Through Raman spectroscopy and thermoporometry, it was found that the strength of the carbon fiber decreased with increasing voids and defects within its crystalline regions, which were inherited from the imperfections formed during the initial spinning and stabilization process. In addition, the appropriate oxygen content in oxidized fiber is also an important factor to create strong carbon fiber. Therefore, carbon fiber with better mechanical properties can be produced by the appropriate combination of the initial spinning condition with subsequent heat treatment and carbonization condition.
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