Aging analysis of high voltage silicone rubber/silica nanocomposites under accelerated weathering conditions

Abstract

Silicone rubber (SiR) is extensively used in outdoor insulation and other applications. However, like other polymers, SiR also degrades and lessens its performance in the exposition of environmental stresses. Nanofillers improve the aging behavior of polymeric insulating materials. To investigate the effect of nanosilica on the aging behavior of SiR, we fabricated nanocomposites of SiR with 2.5 wt.% nanosilica (SNC-2.5) and 5 wt.% nanosilica (SNC-5) by mechanical mixing and ultrasonication method. The prepared samples were subjected to uniform ultraviolet (UV) radiation, heat, humidity, salt fog, and acid rain along with neat SiR in cyclic manner at 2.5 kV for 5000 h in a specially fabricated weathering chamber. Neat SiR and both nanocomposites showed gradual decrease in transparency. Random loss and recovery in hydrophobicity and increase and decrease in leakage current (LC) were recorded for all samples, in which SNC-5 showed the best hydrophobic behavior and least LC. For SNC-5, Fourier transform infrared (FTIR) results showed negligible reduction in absorption peaks at important wave-numbers and increase and intactness were observed at absorption peaks related to the hydrophobic methyl group. Scanning electron microscopy (SEM) results also concurred with FTIR, LC measurements, and hydrophobicity analysis.

Long-term aging characteristics of co-filled nano-silica and micro-ATH in HTV silicone rubber composite insulators

“…S2 shows the lowest LC, making it more stable after 9000 h of aging. S2 presented improved breakdown strength (percentage loss) as compared to the samples in Yuan et al 10 In case of Khattak et al, 32 5000 h aging was performed and the obtained results indicated the improved performance of SNC-5 (silicone rubber with 5 wt% nano-SiO 2 ). The overlapping wave number presented better performance of SNC-5 as compared to the SNC-2.5 (silicone rubber with 2.5 wt% nano-SiO 2 ).…”

“…This loss and recovery pattern in hydrophobicity was also observed by other researchers. 32,33 It can be seen from Figure 7 that SV sample losses hydrophobicity from HC1 to HC5 level. The SV sample started with a high HC3 level and then dropping to HC2 level for some time.…”

Life estimation and investigation of dielectric strength of multistressed high‐voltage epoxy micro and nanocomposites

“…Putting fitting parameters of EPNC from Table 3 in (1) and solving for x . The high resistivity of silica and its good interaction at nanoscale with polymer matrix may be the reasons of increased surface resistivity which resulted in relatively less leakage current in the case of the nanocomposite [20, 21].…”

Dough moulding compound reinforced silicone rubber insulating composites using polymerized styrene butadiene rubber as a compatibilizer

“…The thermal degradation resistance of silicone rubber is the best in all kinds of rubbers [7,8]; silicone rubber also has excellent weather resistance, aging resistance and good electrical insulating properties, which make it irreplaceable by other materials [9]. However, the mechanical properties of silicone rubber are poor [10,11]; the addition of inorganic filler, such as silica, to reinforce rubber composite systems has been researched for several decades [12][13][14][15], thus the need for further research. On the other hand, in recent years scholars at home and abroad have been focusing attention on the research of fiber reinforced rubber composites [16][17][18][19].…”