Hydrophobic transfer of RTV silicone rubber aged in single and multiple environmental stresses and the behavior of LMW silicone fluid

Kumagai, Seiji; Yoshimura, Noboru

doi:10.1109/tpwrd.2003.809690

Cited by 47 publications

(16 citation statements)

References 30 publications

(21 reference statements)

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“…It has been shown that diffusion of hydrophobic linear LMW silicon molecules from the bulk to the surface of the plastic could increase the contact angle. [6][7][8][9][10] The slight decrease of the contact angle could be a result of decrosslinking and chain scissions on the surface. Degradation of silicone rubbers in a strongly acidic environment, 3 which is present inside the human body, predominantly occurs through hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

“…Chain scission results in loss of hydrophobicity (since hydrophilic groups are formed) and the migrating LMW compounds are responsible for the hydrophobic recovery of the surface. [6][7][8][9][10] These LMW compounds were found to be linear PDMS with methyl and/or hydroxyl end groups. 11,12 In medical use of silicone rubber there are two factors which are the main reasons for degradation.…”

Section: Introductionmentioning

confidence: 99%

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Degradation of biomedical polydimethylsiloxanes during exposure to in vivo biofilm environment monitored by FE‐SEM, ATR‐FTIR, and MALDI‐TOF MS

Kaali

Momcilovic

Markström

et al. 2009

J of Applied Polymer Sci

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Polymers used for biomedical purposes in medical devices are usually requested to be inert to degradation. This article describes that slow irreversible changes were observed in silicone surfaces exposed to in vivo biofilms even if silicone, in general, is supposed to have excellent long-term properties. Tracheostomy tubes made of silicone rubber were exposed to in vivo biofilm environments in clinical tests for periods of 1, 3, and 6 months. The chemical degradation was monitored by MALDI-TOF MS, ATR-FTIR, and FE-SEM. In addition, the physical changes were monitored by contact angle and hardness measurements. Cyclic polydimethylsiloxane (PDMS) was detected on the surfaces of new (unaged) silicones. On the surfaces of the in vivo samples new compounds, presumably linear methyl-hydroxyl-terminated PDMS, were detected in addition to cyclic PDMS. These compounds may be formed as a result of the hydrolysis of linear dimethyl terminated PDMS, which is also present in the silicone rubber. ATR-FTIR spectroscopy confirmed that hydrolysis had indeed occurred during the in vivo exposure, since SiAOH groups were detected. Furthermore, significant changes in the topography were detected by FE-SEM, indicating the initiation of degradation. No significant changes in the contact angle of the in vivo used samples were observed, but this information may be shielded by the fact that biofilm may remain on the surface, despite the thorough cleaning before the analysis. It is also possible that the surface hydrophobicity was recovered by the diffusion of linear low-molecular-weight compounds from the bulk.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Degradation of biomedical polydimethylsiloxanes during exposure to in vivo biofilm environment monitored by FE‐SEM, ATR‐FTIR, and MALDI‐TOF MS

Kaali

Momcilovic

Markström

et al. 2009

J of Applied Polymer Sci

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“…The boiling point of silicone oligomer for each size is tabulated in Table 2, in which M means (CH 3 ) 3 SiO 1/2 -and D means -(CH 3 ) 2 SiO-. The different boiling temperatures for the linear and cyclic silicone oligomers signify that a heat treatment at adequate temperature can remove the desired groups of silicone oligomers [8]. Since the cycling temperature range is considerably lower than the boiling points of linear and cyclic silicone oligomers, the loss of the organic materials may be the result of temperature cycling.…”

Section: Tg Analysismentioning

confidence: 99%

“…Due to the promising properties, such as hydrophobicity and transfer of hydrophobicity, room temperature vulcanized (RTV) silicone rubber coatings are widely used to prevent pollution flashover, which has been proven to be effective in the presence of pollution and humidity [4][5][6]. However, numerous aging problems exist in the long-term use of RTV silicone rubbers, which can cause changes in their physical and chemical properties [7,8]. Since testing methods for evaluating the long-term reliability have not been completely standardized, it becomes vitally necessary to assess the effect of environmental factors and operating conditions on the properties of RTV silicone rubbers.…”

Section: Introductionmentioning

confidence: 99%

RTV Silicone Rubber Degradation Induced by Temperature Cycling

et al. 2017

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Room temperature vulcanized (RTV) silicone rubber is extensively used in power system due to its hydrophobicity and hydrophobicity transfer ability. Temperature has been proven to markedly affect the performance of silicone rubbers. This research investigated the degradation of RTV silicone rubber under temperature cycling treatment. Hydrophobicity and its transfer ability, hardness, functional groups, microscopic appearance, and thermal stability were analyzed using the static contact angle method, a Shore A durometer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetry (TG), respectively. Some significant conclusions were drawn. After the temperature was cycled between −25 • C and 70 • C, the hydrophobicity changed modestly, but its transfer ability changed remarkably, which may result from the competition between the formation of more channels for the transfer of low molecular weight (LMW) silicone fluid and the reduction of LMW silicone fluid in the bulk. A hardness analysis and FTIR analysis demonstrated that further cross-linking reactions occurred during the treatment. SEM images showed the changes in roughness of the RTV silicone rubber surfaces. TG analysis also demonstrated the degradation of RTV silicone rubber by presenting evidence that the content of organic materials decreased during the temperature cycling treatment.

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“…So the hydrophobicity recovery performance of SIR, especially after corona deterioration, has been investigated by many researchers [7][8][9][10][11]. According to the previous study, most of researchers believe that the stronger the corona strength or the longer the corona duration, the severer the corona deterioration, the quicker the hydrophobicity recovery.…”

Section: Introductionmentioning

confidence: 99%

Effect of corona intensity on the hydrophobicity recovery characteristics of HTV silicone rubber

Liu

Liang

et al. 2008

2008 International Symposium on Electrical Insulating Materials (ISEIM 2008)

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This paper has investigated the influence of corona intensity on the hydrophobicity recovery characteristics of HTV silicone rubber (SIR) deteriorated by corona discharge. The accelerating aging experiments of HTV silicone rubber were carried out with five levels of corona voltage. The hydrophobicity recovery with time was measured by static contact angle method. The experimental results show that the hydrophobicity of HTV silicone rubber can get some recovery after the corona deterioration, and the corona intensity play an important role on static contact angle of HTV SIR. In general, the procedure of hydrophibicity recovery would be varied with the different corona intensity and varied corona deterioration duration. And the hydrophibicity would not be recovered as original when the corona intensity is high enough under an certainty deterioration duration time.

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Hydrophobic transfer of RTV silicone rubber aged in single and multiple environmental stresses and the behavior of LMW silicone fluid

Cited by 47 publications

References 30 publications

Degradation of biomedical polydimethylsiloxanes during exposure to in vivo biofilm environment monitored by FE‐SEM, ATR‐FTIR, and MALDI‐TOF MS

Degradation of biomedical polydimethylsiloxanes during exposure to in vivo biofilm environment monitored by FE‐SEM, ATR‐FTIR, and MALDI‐TOF MS

RTV Silicone Rubber Degradation Induced by Temperature Cycling

Effect of corona intensity on the hydrophobicity recovery characteristics of HTV silicone rubber

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