メガヘルツ領域における高分子溶液の粘弾性 : ポリスチレン-ジブチルフタレート溶液

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The ultrasonic absorption in solutions of polystyrene in dibutylphtalate was measured in the frequency range from 1 to 52 MHz. The measuring temperature range was from 5 to 65℃. and the concentration of the solution was up to about 8g/100ml. The molecular weight of the sample of polystyrene was 3.0×10^6. The ultrasonic velocity, density and absorption coefficient of the solution increased linearly with the increase of the concentration of polymer over the while temperature range. The plot ⊿α/f^2 against the frequency showed a relaxation curve of single relaxation. With the temperature rise, the relaxation frequency f_r increased, and the absorption maximum per wavelength μ_<max> showed the maximum. The imaginary part of the bulk modulus K" and shear modulus, G" were calculated from the data of ultrasonic absorption and those of Moore et al. ⊿K" and ⊿G" were increased were with the increase of the concentration and frequency. The ratio, ⊿K"/⊿G" is far greater than 1, and the ratio of ⊿_<K'> (Bulk viscosity) to ⊿η' (Shear viscosity) was 2.2 at 25℃. From the temperature dependence of the partial specific compressibility and the partial molar volume, it is suggested that the polymer chains in the solution began to rotate freely above 35℃. The energy difference and the activation energy were estimated from the temperature change of the absorption on the bases of two state model. The following values were obtained ; the energy difference ⊿H_0=1.66kcal/mol, and the activation energy ⊿H<21>=6.6Kcal/mol.
社団法人日本材料学会の論文
1971-05-15

メガヘルツ領域における高分子溶液の粘弾性 : ポリスチレン-ジブチルフタレート溶液

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