scholarly journals Surface Recovery Investigation of Silicone Rubber Composites for Outdoor Electrical Insulation under Accelerated Temperature and Humidity

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3024
Author(s):  
M. Hassan Raza ◽  
Abraiz Khattak ◽  
Asghar Ali ◽  
Safi Ullah Butt ◽  
Bilal Iqbal ◽  
...  
Keyword(s):  
High Temperature ◽  
Silicone Rubber ◽  
Room Temperature ◽  
Nano Silica ◽  
Rubber Composites ◽  
Temperature And Humidity ◽  
Before And After ◽  
Overall Performance ◽  
Alumina Trihydrate ◽  
Better Than

Degradation of silicon rubber due to heat and humidity affect its performance in outdoor applications. To analyze the effects of high temperature and humidity on room temperature vulcanized (RTV) silicone rubber (SiR) and its composites, this study was performed. Five different sample compositions including neat silicone rubber (nSiR), microcomposites (15 wt% silica(SMC 15% SiO2) and 15 wt% ATH(SMC 15% ATH), nanocomposite (2.5 wt% silica(SNC 2.5% SiO2) and hybrid composite (10 wt% micro alumina trihydrate with 2 wt% nano silica(SMNC 10% ATH 2% SiO2) were prepared and subjected to 70 ˚C temperature and 80% relative humidity in an environmental chamber for 120 h. Contact angle, optical microscopy and Fourier transform infrared (FTIR) spectroscopy were employed to analyze the recovery properties before and after applying stresses. Different trends of degradation and recovery were observed for different concentrations of composites. Addition of fillers improved the overall performance of composites and SMC 15% ATH composite performed better than other composites. For high temperature and humidity, the ATH-based microcomposite was recommended over silica due to its superior thermal retardation properties of ATH. It has been proved that ATH filler is able to withstand high temperature and humidity.

Effect of Temperature on Tensile Properties of Vulcanized Rubber

1934 ◽  
Vol 7 (2) ◽  
pp. 371-386
Author(s):  
A. A. Somerville ◽  
W. F. Russell
Keyword(s):  
High Temperature ◽  
Tensile Properties ◽  
Room Temperature ◽  
Point Of View ◽  
Effect Of Temperature ◽  
Curing Conditions ◽  
Vulcanized Rubber ◽  
Before And After ◽  
Temperature Test ◽  
Better Than

Abstract The tensile properties and tear resistance of a large number of commercial inner tubes, before and after aging by different methods, are studied at 0°, 25°, and 100° C. A number of uncured bus-truck tube stocks are also studied from the point of view of their capacity to withstand high temperatures. The effect of testing rubber at 100° C. as compared with room temperature is discussed; how some compounds collapse at 100° C., while others have tensile properties equal to, or better than those at 25°, is shown. The effect of testing artificially aged specimens at 100° C., as well as at 25° C., is discussed; the high-temperature test may reveal conditions of deterioration and overcure that are not noticeable in the 25° tests. The compounding and curing conditions that lead to high tensile properties at 100° C., as well as those which cause inferior quality, are discussed.

Deformation of an extruded nickel beryllide between room temperature and 820 °C

1991 ◽  
Vol 6 (12) ◽  
pp. 2653-2659 ◽  
Author(s):  
G.M. Pharr ◽  
S.V. Courington ◽  
J. Wadsworth ◽  
T.G. Nieh
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Flow Stress ◽  
Strain Hardening ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Compression Tests ◽  
Tension And Compression ◽  
Better Than

The mechanical properties of nickel beryllide, NiBe, have been investigated in the temperature range 20–820 °C. The room temperature properties were studied using tension, bending, and compression tests, while the elevated temperature properties were characterized in compression only. NiBe exhibits some ductility at room temperature; the strains to failure in tension and compression are 1.3% and 13%, respectively. Fracture is controlled primarily by the cohesive strength of grain boundaries. At high temperatures, NiBe is readily deformable—strains in excess of 30% can be achieved at temperatures as low as 400 °C. Strain hardening rates are high, and the flow stress decreases monotonically with temperature. The high temperature strength of NiBe is as good or better than that of NiAl, but not quite as good as CoAl.

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

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 717 ◽  
Author(s):  
Chao Wu ◽  
Yanfeng Gao ◽  
Xidong Liang ◽  
Stanislaw M. Gubanski ◽  
Qian Wang ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Power Transmission ◽  
Mechanical Performance ◽  
Filler Content ◽  
Low Frequency ◽  
Mechanical Tests ◽  
Nano Silica ◽  
Rubber Composites ◽  
Rubber Composite ◽  
Surface Modified

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 10−4–1 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.

Evaluation of the Hydrophobicity on Silicon Rubber Coating with Loads of Alumina Trihydrate and Nanosilica for Use in Electrical Insulation Coatings

2015 ◽  
Vol 820 ◽  
pp. 405-410
Author(s):  
Daniella Cibele Bezerra ◽  
Ignat Pérez Almirall ◽  
Edson Guedes da Costa ◽  
Ana Cristina Figueiredo de Melo Costa ◽  
Edcleide Maria Araújo
Keyword(s):  
Silicone Rubber ◽  
Room Temperature ◽  
Salt Spray ◽  
Rubber Matrix ◽  
Spray Chamber ◽  
Heterogeneous Distribution ◽  
The Matrix ◽  
Rubber Coating ◽  
Rubber Coatings ◽  
Alumina Trihydrate

This study aims to evaluate the hydrophobicity of vulcanized silicone rubber coatings at room temperature (RTV SR) with loads of alumina trihydrate (ATH) and nanosilica (NS) in the polymeric silicone rubber matrix, in order to obtain coatings ATH/NS/RTV SR to cover the surface of glass electrical insulators. The coatings were characterized by scanning electron microscopy (SEM), testing in salt spray chamber, loss test and recovery of hydrophobicity. These coatings showed varying sizes of agglomerates and heterogeneous distribution of particles within the matrix RTV SR. In the test in salt spray chamber smaller leakage current values was observed for the insulator coating with the ATH/NS loads. In the loss and recovery of the hydrophobicity test the best result was observed for insulating load RTV SR / 20: 1 (ATH: NS).

“House-of-cards” structures in silicone rubber composites for superb anti-collapsing performance at medium high temperature

RSC Advances ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 7970-7976 ◽  
Author(s):  
Xinping Zhang ◽  
Yinyan Guan ◽  
Yue Xie ◽  
Dong Qiu
Keyword(s):  
High Temperature ◽  
Silicone Rubber ◽  
Polymer Nanocomposite ◽  
Rubber Composites ◽  
House Of Cards ◽  
Polymer Decomposition

We have introduced a novel polymer nanocomposite with superb anti-collapsing performance after polymer decomposition.

Processing, mechanical properties and oxidation behavior of TaC and HfC composites containing 15 vol% TaSi2 or MoSi2

2009 ◽  
Vol 24 (6) ◽  
pp. 2056-2065 ◽  
Author(s):  
Diletta Sciti ◽  
Laura Silvestroni ◽  
Stefano Guicciardi ◽  
Daniele Dalle Fabbriche ◽  
Alida Bellosi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Mechanical Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
Oxidation Behavior ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Better Than

Fully dense HfC and TaC-based composites containing 15 vol% TaSi2 or MoSi2 were produced by hot pressing at 1750–1900 °C. TaSi2 enhanced the sinterability of the composites and nearly fully dense materials were obtained at lower temperatures than in the case of MoSi2-containing ones. The TaC-based composites performed better than HfC composites at room temperature, showing values of mechanical strength up to 900 MPa and a fracture toughness of 4.7 MPa·m1/2. However, preliminary oxidation tests carried out in air at 1600 °C revealed that HfC-based composites have a superior high temperature stability compared to TaC-based materials.

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