K. Izumi's research while affiliated with Central Research Institute of Electric Power Industry and other places
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Publications (8)
This paper describes the effect of blending of
poly(trifluoropropylmethylvinylsiloxane) (PTFPMVS) with
poly(dimethylsiloxane) (PDMS) on the surface properties of the blend,
such as hydrophobicity. We have investigated the surface molecular
mobility of the PDMS/PTFPMVS blends via dynamic contact angle
measurements and adhesion tension relaxation. We...
Analysis using gas chromatography/mass spectroscopy (GC/MS) was
performed for evaluation of surface degradation of silicone insulating
materials. Silicones are used as coatings for porcelain insulators and
shed material for high voltage composite insulators. A comparison
between virgin silicone rubber and aged silicone rubber samples, which
were ag...
Silicone-based materials for outdoor insulators have the advantage
that low molecular weight (LMW) components migrate through the material
and coat the surface, thereby restoring hydrophobicity over a period of
hours. By measuring the IR absorption of siloxane migrating to the
silicone surface through a thin carbon coating, the time constant for
mi...
Polymer insulator has the advantage of light weight, high strength
and high performance on antipollution. At the present, polymer insulator
is being tested on AC transmission lines and a few DC transmission lines
in Japan. This paper reports on the surface degradation and
characteristics of leakage current on silicone rubber (SR) under DC(+)
and AC...
Thermogravimetric analysis (TGA) was used to evaluate the surface
degradation of polymer insulators designed for outdoor high voltage
applications. Such insulators are usually formed as a composite of
silicone matrix and inorganic materials, such as aluminum trihydrate
(ATH) filler and/or fumed silica. However, the surface of insulators is
subject...
The present contribution describes an analytical technique which
can be used to investigate degradation phenomena of silicones and
provide a quantitative evaluation of surface degradation. The technique
employed in the present investigation is based on the use of gas
chromatography/mass spectrometer (GC/MS) methods
Some artificial aging tests were performed using test rods made of
Silicone Rubber (SR) and Ethylene Propylene Rubber (EPDM), based on the
Rotating Wheel Dip Test (RWDT) method and the Salt Fog Chamber Test
(SFCT) method, and aspects of the surface degradation were evaluated.
Following the tests, it was concluded that the surface degradation of
pol...
Artificial aging tests are performed using test rods made of
silicone rubber (SR) and ethylene propylene diene monomer (EPDM), based
on the rotating wheel dip test (RWDT) method and the salt chamber test
(SFCT) method. Aspects of surface degradation are evaluated. It is
concluded that the surface degradations of polymer insulating materials
are dir...
Citations
... For all samples, the TGA curves obtained their weight loss at a temperature of 500˚C tended to decrease of 89% for the virgin sample, 79% for the samples after ageing 60 h and 70% for the samples after ageing 120 h. This result indicates that the weight loss of the samples after the accelerated ageing process was slightly higher than the virgin sample, according to comparison of TGA curves for the virgin and aged silicone rubber material caused by depolymerisation of the siloxane matrix during the ageing process [245]. The weight loss rate of silicone elastomer can be divided into three main phases of temperature, which consisted of the low molecular weight silicone at 310˚C, the maximum weight loss due to decomposition of the crosslinked silicone elastomer at 450˚C and the formation of the silica glass, including loss of carbon on the bulk of molecular structures between 630˚C and 670˚C [246]. ...
... Discoloration of EPDM due to aging has been reported previously by many authors [260][261][262][263][264]. Higher discoloration of composites in comparison to neat samples was also recently reported by Fairus, M et al in [265]. ...
... A FTER about 7 years of aging at the Millstone NGS on the Connecticut coast, the RTV silicone coatings on station post insulators have depolymerized substantially resulting in conversion of low molecular weight (LMW) PDMS ( to 15 DMS units) to to 5 units, which are of such low molecular weight that they are volatile and much more easily washed off the surface (Fig. 1).Fig. 2 shows the mass spectrum of LMW PDMS components with 3, 4, and 5 PDMS units which indicate that these components are primarily cyclic in nature [1]. The recent measurements in [2] confirm this finding. ...
... In order for a surface to be superhydrophobic, it should have a water contact angle of 150 • or greater [6,7]. Silicone rubber (SR) as a polymer has a high hydrophobicity due to an inorganic backbone of Si-O that attaches to the organic groups (frequently methyl) [8][9][10][11]. SR is commonly used in many fields such as fabrication of electrical insulators [12], biomedicine, machinery, electronics and food processing [13] due to its excellent resistance, low toxicity [14], super transparency, high thermal stability [15], and hydrophobicity. ...
... Here, the m/z of 73, 147 and 221 correspond to the structure of [+Si(CH 3 ) 3 ], [+(CH 3 ) 2 SiOSi(CH 3 ) 3 ], and [+((CH 3 ) 2 SiO) 2 Si(CH 3 ) 3 ], which originate from the methyl shift process after the electron impact. By contrast, the m/z of 207, 281 results from the loss of a methyl group (CH 3 ) in D 3 and D 4 , respectively [19]. The results indicate that peaks from N-1 to N-19 are also siloxanes, judging by the distinctive mass number, that is, m/z of 73, 147, 207, 221 and 281. ...
