| Summary: | 碩士 === 國立交通大學 === 材料科學與工程系 === 89 === Miscibility in blends of random liquid crystalline copoly(oxybenzoate -ethylene terephthalate) at molar ratio 60/40 (P64) and spolyamide 6,6 (PA66) were investigated with differential scanning calorimetry, wide angle X-ray diffraction and polarized optical micrography. It was found that P64 and PA66 were partially miscible as evidenced from the appearance of a single glass transition temperature for each blend at different composition. At the melt state, the Flory-Huggins interaction parameter, 12, which was determined to be — 0.19 through the melting point depression analysis. The coherence lengths of PA66 in the presence of a small amount (around 7 wt%) of P64 were larger than that in pure PA66.
The isothermal and non-isothermal crystallization behaviour in blends of P64 and PA66 were studied with differential scanning calorimetry. In isothermal crystallization experiment, the Avrami exponent were found to decrease with increase the concentrate of P64 and the crystallization rate coefficient had largest value in the small amount (7%) of P64. In non-isothermal crystallization experiment, we found that the Ozawa equation can not work on our case. We selected another one equation to discuss our results.
The 13C nuclear magnetic resonance was found that the ester —amide exchange in the two polymers took place within 10 min when the blend was annealed at 300oC.
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