| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 92 === New miscible blend systems comprised of poly(p-vinyl phenol) (PVPh) and a homologous series of polyesters of different CH2/COO ratios were investigated by using differential scanning calorimeter (DSC), polarized-light microscopy (POM), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR). The series blends of PVPh/PEAz、PVPh/PHA and PVPh/PHS all exhibit a single composition-dependent glass transition and homogeneous phase morphology. Kovacs equation is used to explained the Tg-composition relationship and the g values of PVPh/PEAz、PVPh/PHA、PVPh/PHS blends are 0.010, 0.010 and 0.018, respectively.
Binary interaction strengths in these series of miscible blends were quantitatively compared. FT-IR study showed evidence of hydrogen-bonding interactions between the two polymers in blends. The quantitative Flory-Huggins interaction parameters (��12) obtained from analysis of melting point depression are -1.230, -0.416 and -0.167 for PVPh/PEAz, PVPh/PHA and PVPh/PHS, respectively. The negative values proving that the blends are miscible in a wide temperature range from ambient up to high temperatures in the melt state.
The rate of nucleation and growth crystallization was affected by miscible components in the blends on the basis of Avrami model.
When using THF casting, the blends of PVPH/PEAz and PVPh/PHS are apparently immiscible. However, with increasing the temperatures, the blends become miscible. Utilizing different solvents and methods to prepare the binary blends it is further proved that no UCST behavior exists and the phase separation is induced by solvent.
|
|---|
