Polyblend samples of chitosan/poly(vinyl alcohol) (PVA) have been prepared using a casting technique. Scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis measurements revealed that chitosan and PVA are compatible with each other. Alternate current (AC) conductivity and dielectric relaxation features of pure and polyblend samples are analysed in the frequency range of 0.1 Hz to 100 kHz covering a broad temperature range from room temperature to 423 K. Variation of AC conductivity, σ AC , of pure and chitosan/PVA polyblend samples is found to be characterized by a plateau region at low frequency and high temperature, and this plateau region increases with increase in temperature. Based on the behaviour of the exponent s vs. temperature, AC conductivity dependence on frequency is found to be correlated with overlapping-large polaron tunnelling (OLPT) model. The polyblend samples showed an improvement in their dielectric properties compared to the pure materials. The dielectric constant, ε ′, of polyblend samples was increased by increasing the content of PVA. The dielectric dispersion was observed in the variation of ε ′ against frequency for all samples. The high values of ε ′ for all samples at high temperature and low frequency are attributed to space charge polarization. Also, loss tangent-frequency behaviour of pure chitosan, PVA and all polyblend samples showed two distinguished relaxation peaks with different values of activation energies. The first relaxation peak is termed as interfacial polarization or Maxwell–Wagner–Sillars polarization due to heterogeneity of the polyblend samples, whereas, the second relaxation peak is termed as δ-relaxation and α-relaxation, for pure chitosan and PVA, respectively.

中文翻译：

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壳聚糖/聚乙烯醇生物聚合物共混物的交流电导率和介电弛豫

使用浇铸技术制备了壳聚糖/聚乙烯醇 (PVA) 的共混物样品。扫描电子显微镜、傅里叶变换红外光谱和热重分析测量表明壳聚糖和 PVA 相互兼容。在 0.1 Hz 至 100 kHz 的频率范围内分析纯样品和多混合物样品的交流电 (AC) 电导率和介电弛豫特性，覆盖了从室温到 423 K 的广泛温度范围。发现壳聚糖/PVA 共混物样品在低频和高温下具有平台区的特征，并且该平台区随着温度的升高而增加。基于指数 s 与温度的关系，交流电导率对频率的依赖被发现与重叠大极化子隧穿 (OLPT) 模型相关。与纯材料相比，共混物样品的介电性能有所改善。通过增加 PVA 的含量，共混物样品的介电常数 ε ' 增加。在所有样品的 ε ' 随频率的变化中观察到介电色散。所有样品在高温和低频下的高 ε ' 值归因于空间电荷极化。此外，纯壳聚糖、PVA 和所有共混物样品的损耗角正切频率行为显示出两个具有不同活化能值的显着弛豫峰。