Kúdelčík Jozef, Hardoň Štefan, Trnka Pavel, Michal Ondřej, Hornak Jaroslav
Department of Physics, Faculty of Electrical Engineering and Information Technology, University of Žilina, 010 26 Žilina, Slovakia.
Department of Materials and Technology, Faculty of Electrical Engineering, University of West Bohemia, 306 14 Pilsen, Czech Republic.
Polymers (Basel). 2021 Jan 26;13(3):375. doi: 10.3390/polym13030375.
The influence of different concentrations (0.5, 1.0, and 2.0 wt.%) of Zinc Oxide (ZnO) filler on the dielectric properties of the cold-curing polyurethane (PU) resin is presented in this study. For this purpose, the direct DC conductivity and the broadband dielectric spectroscopy measurements were used to describe the changes in dielectric responses of PU/ZnO nanocomposites over the frequency and temperature range, respectively. It can be stated that, the 1.0 wt.% nanoparticles and lower caused a decrease in the real relative permittivity compared to the pure PU resin, while the higher concentration of nanoparticles for frequencies above 1 Hz had the opposite effect. The presence of nanoparticles in the polyurethane resin affected the segmental dynamics of the polymer chain and changed a charge distribution in the given system. These changes caused a shift of local relaxation peaks in the spectra of imaginary permittivity and dissipation factor of nanocomposites. It is suggested that the temperature-dependent transition of the electric properties in the nano-composite is closely associated with the α-relaxation and intermediate dipolar effects (IDE).
本研究展示了不同浓度（0.5、1.0和2.0重量%）的氧化锌（ZnO）填料对冷固化聚氨酯（PU）树脂介电性能的影响。为此，分别使用直流直流电导率和宽带介电谱测量来描述PU/ZnO纳米复合材料在频率和温度范围内介电响应的变化。可以说，与纯PU树脂相比，1.0重量%及更低浓度的纳米颗粒导致实部相对介电常数降低，而对于高于1 Hz的频率，较高浓度的纳米颗粒则产生相反的效果。聚氨酯树脂中纳米颗粒的存在影响了聚合物链的链段动力学，并改变了给定系统中的电荷分布。这些变化导致纳米复合材料虚部介电常数和损耗因子谱中局部弛豫峰的移动。研究表明，纳米复合材料中电性能的温度依赖性转变与α弛豫和中间偶极效应（IDE）密切相关。
