Investigation on permeation properties of liquids into HTV silicone rubber materials

Abstract

In this paper, the permeation properties of three types of liquids into HTV silicone rubber with different Alumina Tri-hydrate (ATH) contents had been investigated by weight gain experiments. The influence of differing exposure conditions on the diffusion into silicone rubber, in particular the effect of solution type, solution concentration, and test temperature were explored. Experimental results indicated that the liquids permeation into silicone rubber obeyed anomalous diffusion ways instead of the Fick diffusion model. Moreover, higher temperature would accelerate the permeation process, and silicone rubber with higher ATH content absorbed more liquids than that with lower ATH content. Furthermore, the material properties of silicone rubber before and after liquid permeation were examined using Fourier infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. The permeation mechanisms and process were discussed in depth by combining the weight gain experiment results and the material properties analyses.

Study on the interface partial discharge between silicone rubber and fiber reinforced plastic in composite insulators

“…After that, discharge of thousands of pC was detected and breakdown happened through the interface between silicone rubber and FRP after few seconds under the applied voltage of 14.2kV. In our previous study, when silicone rubber were immersed in water, weight gain approached saturated condition after 20 days [6]. The water invaded to the interface had influenced the electrical properties of the insulation.…”

“…On the one hand, the water molecules and ions in the HN03 had the same influence on the insulation with deionized water and NaCI solution. On the other hand, a chemical reaction progress between RN03 and fillers of silicone rubber happened, with holes and cracks on the surface of silicone rubber by SEM [6]. The accumulated acid would cause the deterioration of silane coupling agent and bonding of the interface.…”

“…When there are small gaps at the interface, water molecules in deionized water and NaCl solution would fill the gaps and change the electrical field of the interface, which caused more discharge magnitude and even breakdown under a low voltage. Reference [6] found that deionized water diffused into the silicone rubber layer more easily then NaCl solution, and the liquids accumulation at the interface w expected to be much more. When high voltage applied, the specimens in deionized water had larger discharge magnitude and were more easy to breakdown.…”

Corona degradation of the polymer insulator samples under different fog conditions

“…It is observed from the figure 6a that there is a prominent peak appearing at 1650 cm -1 and 1360 cm -1 (encircled with numbers 1 for 1650 cm -1 and 2 for 1360 cm -1 ). This provides evidence for the introduction of nitric acid to the PDMS [27]. These peaks represent the formation of aluminum nitrites which are introduced because of the reaction of alumina trihydrate with the nitric acid giving rise to the aluminum nitrite nonahydrate [28].…”

Effect of aluminum hydroxide on low‐molecular‐weight siloxane distribution and microstructure of high‐temperature vulcanized silicone rubber

“…Dehydration of ATH can also suppress the surface erosion induced by dry band arc discharge . Gao et al . studied the water permeation properties of HTV silicone rubber with different ATH contents and concluded that silicone rubber with low ATH content performed better than that with high ATH content.…”