Sanida Aikaterini, Stavropoulos Sotirios G, Speliotis Thanassis, Psarras Georgios C
Smart Materials & Nanodielectrics Laboratory, Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece.
Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", Aghia Paraskevi, 15310 Athens, Greece.
Materials (Basel). 2019 Sep 17;12(18):3015. doi: 10.3390/ma12183015.
In this study nanocomposites consisting of an epoxy resin and ceramic zinc ferrite nanoparticles have been successfully developed and investigated morphologically and structurally by means of scanning electron microscopy (SEM) images and X-ray diffraction (XRD) spectra. The thermal properties of the nanocomposites were studied via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermomechanical characterization of the fabricated nanocomposites was studied via dynamic mechanical analysis (DMA) and the magneto-dielectric response was assessed by means of a broadband dielectric spectroscopy (BDS) and by employing a superconducting quantum interference device (SQUID) magnetometer. Data analysis demonstrates that the incorporation of nanoinclusions into the matrix improves both the thermomechanical and the dielectric properties of the systems, as indicated by the increase of the storage modulus, the real part of dielectric permittivity and conductivity values with filler content, while at the same time induces magnetic properties into the matrix. Zinc ferrite nanoparticles and their respective nanocomposites exhibit superparamagnetic behavior at room temperature. Three relaxations were recorded in the dielectric spectra of all systems; originating from the filler and the polymer matrix, namely interfacial polarization, glass to rubber transition of the polymer matrix and the reorientation of small polar side groups of the polymer chain.
在本研究中，由环氧树脂和陶瓷锌铁氧体纳米颗粒组成的纳米复合材料已成功制备，并通过扫描电子显微镜（SEM）图像和X射线衍射（XRD）光谱对其形态和结构进行了研究。通过差示扫描量热法（DSC）和热重分析（TGA）研究了纳米复合材料的热性能。通过动态力学分析（DMA）研究了制备的纳米复合材料的热机械性能，并通过宽带介电谱（BDS）和超导量子干涉仪（SQUID）磁力计评估了磁电响应。数据分析表明，将纳米夹杂物掺入基体中可改善体系的热机械性能和介电性能，这表现为储能模量、介电常数实部和电导率值随填料含量的增加而增大，同时使基体具有磁性。锌铁氧体纳米颗粒及其相应的纳米复合材料在室温下表现出超顺磁性行为。在所有体系的介电谱中记录到三种弛豫现象；它们分别源于填料和聚合物基体，即界面极化、聚合物基体的玻璃态到橡胶态转变以及聚合物链小极性侧基的重新取向。
