Dielectric relaxation of poly(vinyl acetate)
Dielectric relaxation of poly(vinyl acetate)
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聚醋酸乙烯酯的介电弛豫
DOI：
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发表时间：
1982
期刊：
影响因子：
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通讯作者：
S. Takeishi
中科院分区：
文献类型：
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作者：
S. Mashimo;R. Nozaki;S. Yagihara;S. Takeishi
在288<T<366 K，1 μHz ~ 150 MHz的极宽频率范围内测量了未稀释和稀释的聚醋酸乙烯酯（PVAc）的介电弛豫。复介电常数可以通过Havriliak-Negami方程e*=e∞+Δe[1+（jωτ0）β]−α，0<α，β≤1定量描述。发现参数α由偶极矩比g的线性方程α=1.09-0.91g给出。这一观察结果表明，α与局部链构象密切相关。另一方面，在玻璃化转变温度以上，β几乎是常数<$0.87，并且与稀释剂的影响无关。这表明β的恒定值是PVAc弛豫谱的固有特征。
Dielectric relaxation measurements of undiluted and diluted poly(vinyl acetate) PVAc have been made at temperatures 288<T<366 K over an extremely wide frequency range from 1 μHz to 150 MHz. The complex permittivity can be described quantitatively by the Havriliak–Negami equation e*=e∞+Δe[1+(jωτ0)β]−α, 0<α, β≤1. It has been found that the parameter α is given by a linear equation of dipole moment ratio g as α=1.09–0.91g. This observation suggests that α is connected closely with local chain conformations. On the other hand, β is nearly constant ∼0.87 above the glass transition temperature and is independent of effect of the diluent. This suggests that the constant value of β is an inherent characteristic of the relaxation spectrum of PVAc.