| Summary: | 碩士 === 逢甲大學 === 紡織工程所 === 94 === This thesis investigated the rheological properties of thermoplastic polyvinyl alcohol (TPVA) and of blends with polypropylene (PP). TPVA was prepared via plasticization with glycerin, which has good stability and excellent compatibility with PVA. In the respect of the flow properties of TPVA/PP blend melts, as the blending proportions were approached, the shear dependence of viscosity was lowest and the temperature sensitivity of the viscosity was the highest, and the viscosity reached a minimum. Furthermore, the melt spinning method was used to test the elongational flow properties of TPVA and TPVA/PP blend melts. The test results indicate that TPVA melt with a higher plasticizer concentration or a lower degree of polymerization had higher fiber velocity and elongation rate, but lower elongational resistance. The elongational resistance increased with elongation rate, and reached a plateau at higher elongation rates exhibiting a concave downward curvature. This phenomenon demonstrates no sudden rise occurs in elongational resistance exhibiting lower strain hardening. Regarding the elongational flow properties of the blend melts which was dominated by the drawing ratio, and was also affected by the blending ratios. The blend with approximated blending ratios, the elongation rates increased, but the elongational resistances remain relatively lower.
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