Manifestation of Interactions of Nano-Silica in Silicone Rubber Investigated by Low-Frequency Dielectric Spectroscopy and Mechanical Tests

• Published in: Polymers Vol. 11; no. 4; p. 717
• Main Authors: Wu, Chao, Gao, Yanfeng, Liang, Xidong, Gubanski, Stanislaw M, Wang, Qian, Bao, Weining, Li, Shaohua
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 19-04-2019; MDPI
• Subjects: Chemical elements; Composite materials; dielectric response; Dielectrics; Electric fields; Fillers; Fourier transforms; Frequency ranges; Insulation; interface; Interfaces; Mechanical drives; Mechanical properties; Mechanical tests; Moisture absorption; Morphology; Nanocomposites; Polymers; Power; Power transmission; Rubber; Scanning electron microscopy; silica nanocomposites; Silicon dioxide; Silicone resins; Silicone rubber; Silicones; Spectrum analysis; Strain; Substations; China; silicone rubber; silica nanocomposites; dielectric response; interface; mechanical properties
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym11040717

Silicone rubber composites filled with nano-silica are currently widely used as high voltage insulating materials in power transmission and substation systems. We present a systematic study on the dielectric and mechanical performance of silicone rubber filled with surface modified and unmodified fumed nano-silica. The results indicate that the different interfaces between the silicone rubber and the two types of nano-silica introduce changes in their dielectric response when electrically stressed by a sinusoidal excitation in the frequency range of 10
-1 Hz. The responses of pure silicone rubber and the composite filled with modified silica can be characterized by a paralleled combination of Maxwell-Wagner-Sillars interface polarization and DC conduction. In contrast, the silicone rubber composite with the unmodified nano-silica exhibits a quasi-DC (Q-DC) transport process. The mechanical properties of the composites (represented by their stress-strain characteristics) reveal an improvement in the mechanical strength with increasing filler content. Moreover, the strain level of the composite with a modified filler is improved.