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improvement of Insulation in silicone rubber by adding al2o3 filler

Authors:
Khaja Zaffer at Lisbon School Of Economics and Management
Khaja Zaffer
  • Lisbon School Of Economics and Management
Pulla Sammaiah at SR Engineering College
Pulla Sammaiah
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Abstract and Figures

Polymer Nano composite in recent time has shown high improvement in mechanical, chemical and electrical properties. Granting all these, the use of polymer nano-composites has only recently begun starting explorer. In recent times, polymer materials has shown remarkable improvement in electrical insulation because of their numerous advantages in out-door insulation systems because of their negligible weight, better pollution performance, low cost, good dielectric properties with easy processing. In polymer materials, silicone rubber is one of the lead polymer currently used and has high ending properties like high voltage insulator, thermal stability, excellent UV resistance and hydrophobicity. Therefore, Silicone rubber with fillers can overcome few drawbacks such as low strength and insulating properties.Oxides with different properties can help silicone rubber to enhance its properties. Oxides such as alumina, zirconia are being widely used in silicone rubber. Alumina which has strong thermal conductive and compressive strength with good electrical is used in silicone rubber. Here Silicone rubber nano composites are prepared by incorporating Al2O3 nano partic les. Electrical, Chemical properties like NaCl, HCl, and corrosion tests were conducted to know the performance of silicone rubber insulation at pollutant conditions. Dielectric tests were also done to know whether Al2O3 has made any effect with silicone rubber. Tensile strength and Hardness test were carried out to determine mechanical strength of the rubber.
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International Journal of Innovative Technology and Exploring Engineering (IJITEE)
ISSN: 2278-3075, Volume-8 Issue-10, August 2019
4695
Published By:
Blue Eyes Intelligence Engineering
& Sciences Publication
Retrieval Number I8814078919/2019©BEIESP
DOI: 10.35940/ijitee.I8814.0881019
Khaja Zaffer, Pulla Sammaiah
Abstract: Polymer Nano composite in recent time has shown
high improvement in mechanical, chemical and electrical
properties. Granting all these, the use of polymer nano-composites
has only recently begun starting explorer. In recent times, polymer
materials has shown remarkable improvement in electrical
insulation because of their numerous advantages in out-door
insulation systems because of their negligible weight, better
pollution performance, low cost, good dielectric properties with
easy processing. In polymer materials, silicone rubber is one of
the lead polymer currently used and has high ending properties
like high voltage insulator, thermal stability, excellent UV
resistance and hydrophobicity. Therefore, Silicone rubber with
fillers can overcome few drawbacks such as low strength and
insulating properties.Oxides with different properties can help
silicone rubber to enhance its properties. Oxides such as alumina,
zirconia are being widely used in silicone rubber. Alumina which
has strong thermal conductive and compressive strength with
good electrical is used in silicone rubber. Here Silicone rubber
nano composites are prepared by incorporating Al2O3 nano partic
les. Electrical, Chemical properties like NaCl, HCl, and corrosion
tests were conducted to know the performance of silicone rubber
insulation at pollutant conditions. Dielectric tests were also done
to know whether Al2O3 has made any effect with silicone rubber.
Tensile strength and Hardness test were carried out to determine
mechanical strength of the rubber.
Index Terms: silicone rubbers, aluminium oxide, electrical
insulation, mechanical properties.
I. INTRODUCTION
The word silicone rubber ion was first proposed by
Dumas in 1840. During 19th century, Ladenburg
experimentally produced silicone rubber by reacting
diethoxydiethysilane with water and trace amounts of
acids[1-2]. Dow chemical company first commercially
produced it in 1941. Silicone rubber is a synthetic
elastomer[3]. It is a cross-linked silicon based polymer also
bonded with carbon, hydrogen and oxygen. Silicone can be
distinguished from rubbers by atomic structure. It consists of
a backbone of silicone atoms with alternating oxygen atoms.
He recounted few additional compounds of the generic
formula R2SiO2. These were swiftly identified as being and
actually corresponding to polyialkylsiloxanes, with the
formulation
Revised Manuscript Received on August 05, 2019.
Khaja zaffer, Mechanical Engineering Department, S.R Engineering
College, warangal, India.
Pulla Sammaiah, Mechanical Engineering Department, S.R
Engineering College, warangal, India
Where ‘R’ represents Methyl or Phenyl or Vinyl or
Trifluoropropyl [4].Here “organic” groups are combined with
“inorganic” as a backbone which makes properties of Silicone
rubber unique. Because of Si-O bond attached to the polymer
backbone, the polymer molecular weight and the polymer
conformation are largely affected and these are remarkably
greater and efficient than C-C bond. These Si-O bonds in
silicone have greater stability and resistance to thermal and
thermo oxidative resistance, greater hydrophobicity, flame
retardant [5-7]. Radioactive particles and electromagnetic
were very rarely attacked in “inorganic” silicones. This
allows there use in different sectors like electrical insulation,
aerospace, electronic and medical devices. With the use of
different oxides and Nano Particles silicone can be used in
different industries. Aluminium oxide has various properties
such as wear-resistance, good thermal conductivity, excellent
dielectric properties, high strength and stiffness. In this paper,
silicone rubber is used with and without alumina as a filler,
various insulation, chemical and mechanical tests were
carried out[8-9]. In the upcoming days there would be huge
demand for power and for transmitting high voltage power,
transmitting lines should have good insulating properties,
higher strength, excellent hydrophobicity and high tensile
strength. Porcelin insulators are limited and can not be used at
costal areas and withstand high temperature. Here, we
demonstrated on how silicone rubber improved insulating,
chemical and mechanical Properties
II. EXPERIEMENTAL PROCEDURE
Our Main aim was to create an identical sample which can be
used at high voltage transmit line by using Liquid Silicone
Rubber (LSR). The following are the properties of Liquid
Silicone rubber.
S.No
Description
Parameter
1
Apperance
White
2
Hardness (A)
15
3
Viscocity (CPS 25Oc)
9500
4
Elongation break %
>450
Table 1: specifications of Liquid Silicone Rubber
2.1 Procedure of making Silicone Rubber Spicemen from
Liquid Silicone rubber Without Adding any Fillers.
1. Take G.I sheet of required dimension
(100X1000X4thickness) mm.
2. Fold the sheet in the form of a tray (as per required
thickness).
3. Take the silicone gel in a separate bowl of required
quantity.
4. Add the hardener to silicone gel in required proportion.
5. Stir the mixture properly.
6. Pour the solution into the
tray
Improvement of Electrical Insulation in Silicone
Rubber by Adding Al2O3
Improvement of Electrical Insulation in silicone rubber by adding Al2O3
4696
Retrieval Number I8814078919/2019©BEIESP
DOI: 10.35940/ijitee.I8814.0881019
7. Allow it to solidify (generally it takes 24 hours).
8. After solidification remove the specimen from the tray.
2.2 The following tests were conducted to analyze the
properties of materials:
Megger Test or Resistivity Test:
1. Megger test is done on the specimen to find its resistivity.
2. Two electrodes are placed on the specimen with varying
distances and rotate the handle of machine to generate the
emf.
3. Resistivity values are noted in the table.
Distance between two electrodes
Note: Megger test is done for voltages up to 1000V.
Table 2: Megger Test of Silicone Rubber without Filler.
Thickness
of silicone
rubber
1mm
2mm
3mm
4mm
5mm
2mm
Infinity
Infinity
Infinity
Infinity
Infinity
3mm
Infinity
Infinity
Infinity
Infinity
Infinity
4mm
Infinity
Infinity
Infinity
Infinity
Infinity
Dielectric Strength Test:
This test is done with high electric voltage to know the limit of
insulation for LSR-1 and LSR-2. The specimen is placed
in-between the 2 electrodes to find insulation. The results are
as follows[11-15,23]:
1. Specimen is placed in between the two electrodes.
2. Switch on the mains.
3. Regulate the voltage slowly until the spark is generated.
4. Spark generation indicates that the specimen has reached
its breakdown point.
5. Note the breakdown value.
Liquid Silicone Rubber
KV
LSR (4mm)
15
Table 3: Dielectric Test of Silicone Rubber without filler
Silicone Rubber has insulated the two electrodes from 0KV to
15KV, Spark was formed at 15KV which states that
conductance of electricity from 15 KV.
Figure 1 Dielectric Test Equipment at Electrical Sub
Station
Chemical Test:
(a) Salt test:
1. Sodium Chloride (NaCl) solution is prepared with
concentrations of 0.1N, 1N and 2N[16].
2. Note the weight of specimen before testing.
3. This Specimen is kept in the solution under testing for the
duration of 6 hours, 18 hours and 24 hours.
4. Note the weight of the specimen for each interval.
Table 4: Salt Test of Silicone Rubber without filler
NaCl
Solution
Distilled
water (ml)
Weight of
Silicone
Rubber
Before Test
(gms)
Weight of
Silicone
Rubber
After Test
(gms)
0.1N
100
1.2
1.2
0.2N
100
1.2
1.2
0.3N
100
1.2
1.2
(b) Acid test:
1. Note the weights of specimen before testing[17-18].
2. Specimen is placed in dilute HCl and H2So4 for duration of
6 hours, 18 hours and 24 hours.
3. Weights of the specimens are noted after testing.
Table 5: Acid Test of Silicone Rubber without filler
(c) Corrosion test:
1. Prepare the acidic environment in the presence of
inhibitor[19-22].
2. Weigh the sample by means of an electronic balance and
record the weights of the sample.
3. Immerse samples in the acidic environment in the presence
of inhibitor (immersion period=30 min).
4. After 30 min of immersion period take out the samples, one
by one wash the samples in running water under the tap to
remove the loosely held rust or other corrosion.
5. Rinse the surfaces in acetone.
6. Take them to oven and dry for 5 min.
7. Remove the plates from oven, cool them and weigh them
again.
8. Record these weights.
Table 6: Corrosion Test of Silicone Rubber without
filler
Concentratio
n
Actual Weight
Before Test (gms)
Actual Weight After Test
(gms)
0.1N
1.4
1.4
1N
1.4
1.4
2N
1.4
1.4
H2so4
1.4
1.4
HCl
1.4
1.4
2.3 With addition of Al2O3 Nano particles:
Procedure for preparation ofAl2O3 Nano filler with
silicone rubber for electrical insulation:
1. First, we have calculated the density of silicone rubber and
according to that we have added 5%, 10%, 15% of Al2O3 and
required amount of hardness liquid is added to it.
2. Then we have also added the mixer in cavity for required
shape.
3. The mixer is then heated for 30 min in furnace at 80C so
that Al2O3 can react with silicone rubber and form a stable
state.
4. After that the mixture is left for ample time so that it could
solidify at room temperature.
The following are the calculation taken to produce 4mm of
silicone rubber with Al2O3
as fillers.
Concentratio
n
Actual Weight (gms)
Weight after 24 hours
(gms)
H2So4
1.40
1.40
HCl
1.40
1.40
International Journal of Innovative Technology and Exploring Engineering (IJITEE)
ISSN: 2278-3075, Volume-8 Issue-10, August 2019
4697
Published By:
Blue Eyes Intelligence Engineering
& Sciences Publication
Retrieval Number I8814078919/2019©BEIESP
DOI: 10.35940/ijitee.I8814.0881019
Calculation of Al2O3 for LSR-2:
Density of Al2O3 => 0.00389 gm/mm3
Density of LSR= 1.09 gm / cm3 = 0.00109 gm/mm3
Mass= density x volume
For 100x100x4 dimension, mass = 0.00109 x 10000 =10.9
gm
Available weight of Al2O3 is 2.260gm
For 2.260gms of Al2O3
5% is (2.260 x 5 / 100) = 0.113gms
Similarly, for 10% = 0.226gms
Table 7: Calculation of fillers in LSR
Table 8: Megger Test of Silicone Rubber with Filler.
Dielectric Strength Test:
Liquid Silicone Rubber
KV
LSR (4mm) 5%
17
LSR (4mm) 10%
20
Table 9: Dielectric Test of Silicone Rubber with filler
Silicone Rubber has insulated the two electrodes from 0KV to
15KV, Spark was formed at 15KV which states that
conductance of electricity from 15 KV.
Figure 2: Dielectric Test Equipment at Electrical Sub
Station
Chemical Test:
(a) Salt test:
Table 9 Salt Test of Silicone Rubber with filler
(b) Acid test:
Concentratio
n
Actual Weight
Before Test (gms)
Actual Weight
After Test (gms)
0.1N
1.6
1.6
1N
1.6
1.6
2N
1.6
1.6
H2so4
1.6
1.6
HCl
1.6
1.6
Table 10: Acid Test of Silicone Rubber with filler
(c) Corrosion test:
NaCl
Solution
Distilled
water (ml)
Weight of
Silicone Rubber
Before Test
(gms)
Weight of
Silicone Rubber
After Test (gms)
0.1N
100
1.6
1.6
0.2N
100
1.6
1.6
0.3N
100
1.6
1.6
Table 11: Corrosion Test of Silicone Rubber with
filler
III. RESULT
Dielectric Test:
Dielectric test of Liquid silicone rubber with and without
fillers are carried out.
Table 12: The above table replicates liquid silicone
rubber with and without filler and their insulation in KV.
Figure 3: Dielectric test of LSR with and without filler
The above line graph represents improvement of electrical
insulation when LSR is added with 5% and 10% of Al2O3.
2.4 Hardness and Tensile Strength Test
Because LSR with 10% have shown better electrical
insulation, when compared to LSR with 5%. Hardness and
Tensile Strength Test were carried out for LSR with 10%.
Figure 4: Hardness and Tensile Strength of LSR without
filler
For 95% (LSR2+hardener) +5%
Al2O3
) (gms
For 95%
LSR
weight
9.837
9.319
Hardner
0.517
0.490
Al2O3
0.113
0.226
Thickne
ss of
silicone
rubber
1mm
2mm
3mm
4mm
5mm
2mm
Infinity
Infinity
Infinit
y
Infinity
Infinity
3mm
Infinity
Infinity
Infinit
y
Infinity
Infinity
4mm
Infinity
Infinity
Infinit
y
Infinity
Infinity
Concentrati
on
Actual Weight (gms)
Weight after 24 hours (gms)
H2So4
1.60
1.60
HCl
1.60
1.60
Liquid Silicone Rubber
KV
LSR (4mm) without filler
15
LSR (4mm) 5% of filler
17
LSR (4mm) 10% of filler
20
Improvement of Electrical Insulation in silicone rubber by adding Al2O3
4698
Retrieval Number I8814078919/2019©BEIESP
DOI: 10.35940/ijitee.I8814.0881019
The above graph illustrates that Liquid silicone rubber with
Al2O3 as filler had a peak load of 20.0116 newton, where as
elongation break was at 143.5870%
Figure 5: Hardness and Tensile Strength of LSR with
Filler
The above graph illustrates that Liquid silicone rubber with
Al2O3 as filler had a peak load of 24.3726 newton, where as
elongation break was at 421.3292%
Hence, from the above tests, filler played a pivotal role in not
only improving of electrical insulation but also hardness and
Strength of LSR.
IV. CONCLUSION
The above research is about the development of Silicone
Nano composites for not only outdoor high voltage insulators
but also can be used near by costal areas. Silicone rubber
Nano composites have been prepared by incorporating Al2O3
Nano particles. Electrical and chemical properties of the
Nano composites were investigated. Chemical properties
such as NaCl, Corrosion and Acid tests were conducted to
know the performance of silicone insulation at pollutant
conditions. Dielectric tests were conducted on both LSR with
and without filler. With addition of fillers in silicone rubber
particularly in LSR with 10% 5 KV of electrical insulation
was increased.With addition of Al2O3 as filler insulation has
increased to total of 20KV from 15 KV. Mechanical tests such
as hardness and tensile strength were conducted on Liquid
Silicone rubber without and 10% Al2O3 filler and out of
which 10 % Al2O3 filler in silicone rubber showed huge
strength when compared to without filler. Silicone rubber
without filler showed elongation % of 150 at 20.0 N whereas
silicone rubber with filler had elongation % of 421.3 at peak
load of 24.3 N on Universal Testing Machine.
The results obtained for various tests indicate that the
compatibles of Silicone rubber withAl2O3 have improved
mechanical, thermal and dielectric properties. Silicone
Rubber with Al2O3as a filler would be a better way for high
voltage electrical insulation due to its improved dielectric.
Chemical and mechanical characteristics.
REFERENCES
1. Princy KG, Joseph R, Kartha CS (1998) Studies on conductive
siliconerubbercompounds.JApplPolymSci69(5):1043–1050
2. J.F. Hall, History and bibliography of polymeric insulators for outdoor
applications,IEEE Trans. Power Deliv. 8 (1993) 376–385.
3. Mark JE, Erman B, Eirich FR (1994) Science and technology of
rubber, 2nd edn. Academic, SanDiego
4. A review on silicone rubber by Shubas C, Shit, Pathik Shah
5. S. Kumagai and N. Yoshimura, In: Proc. 1998 international
symposium on electrical insulating materials (Toyohashi, Japan, 1998)
C3.
6. Super-hydrophobic zinc oxide/silicone rubber nanocomposite
surfacesAna Isabel Mendozaa, Rosana Morianaa,b,c, Henrik
Hillborgd, Emma Strömberga,⁎
7. Hydrophobicity of silicone rubber used for outdoor insulation
-Mohammad Amin, Mohammad Akbar and Salman Amin.
8. D.-H. Han, D.-J. Kang, D.-P. Kang, K.-E. Min, Characteristics of
electrical insulationin PDMS-ATH composite for high voltage
insulators, Polym. Bull. 61 (2008)611–617.
9. Hamdani, S.; Longuet, C.; Lopez-Cuesta, J.M.; Ganachaud, F.
Calcium and aluminium-based fillers as flame-retardant additives in
silicone matrices. I. Blend preparation and thermal properties. Polym.
Degrad. Stab. 2010, 95, 1911–1919
10. Hu, S.; Chen, F.; Li, J.G.; Shen, Q.; Huang, Z.X.; Zhang, L.M. The
ceramifying process and mechanical properties of silicone
rubber/ammonium polyphosphate/aluminium hydroxide/mica
composites. Polym. Degrad. Stab. 2016, 126, 196–203.
11. H. Hillborg, U.W. Gedde, Hydrophobicity recovery of
polydimethylsiloxane afterexposure to corona discharges, Polymer 39
(1998) 1991–1998.
12. Raji Sundararajan, Areef Muhammad, Noppom Chaipanit, Tim
Karcher and Zhenquan Liu // IEEE trans on dielectric and electrical
insulation 11 (2004) 348.
13. J. Lambrecht, R. Basch, S.M. Guhski and M.A. Fernando, In:
Proc.1998 IEEE international conference on conduction and
breakdown in solid dielectrics (1998, Vasteris, Sweden) p. 430.
14. K. Naito R. Matsuoka, T. Irie and K. Kondo // IEEE. transactions on
dielectric and electrical insulation 6 (1999) 732.
15. S. Shihab, V.Melik, L.Zhou, G.Melik and N.Alame, In: Proceedings of
the 4th international conference on properties and applications of
dielectric materials (Brisbane, Australia, 1994) p. 530.
16. V.M. Moreno-Villa, M. A. Ponce-Velez, E. VaIIe-Jaime and J.L.
Fierro-Chavez // IEE Proc.-Gener. Transm. 145 (I998) 675
17. Polymer Data Handbook (Oxford University Press, Inc, 1999).
18. X. Wang, S. Kumagai and N. Yoshimura, In: Proc. of 1998
International symposium on electrical insulating materials (Toyohashi,
Japan, 1998) p. 619.
19. K. Seog-Hyeon, E.A. Cherney, R. Hackam, K.G. Rutherford, Chemical
changes at thesurface of RTV silicone rubber coatings on insulators
during dry-band arcing,
20. A Suzuki, T. Kumai, M. Hidaka, R. Kishida, N. Toshima, Y. Koshino,
K. Sakanish, Y. Utsumi and Higashi Ku, deterioration diagnosis
technique of housing rubber for composite hollow insulator (NGK
review overseas, edition No. 27, Dec. 2003).
21. E Sherif and C. Andreasson, Results from long term tests with long rod
composite insulators exposed to natural pollution (NordIS 84, 1984
22. H Homma, T. Kuroyagi, K. Izumi, C. L. Mirley, J. Ronzello and S. A. //
IEEE transactions on power delivery 15 (2000).
23. T.G. Gustavsson, S.M. Gubanski, H. Hillborg, S. Karlsson, U.W.
Gedde, Aging ofsilicone rubber under ac or dc voltages in a coastal
environment, Dielectr. Electr.Insul. IEEE Trans. 8 (2001) 1029–1039.
AUTHORS PROFILE
Khaja zaffer, He has worked as research analysist
before joining EPE PVT limited as floor supervisor in
fabrication department. He has worked in Talla
padmavathi college of Engineering as an assistant
professor during which he got more interest on
discovering something new.
Pulla Sammaiah, Currently working as Dean and HOD
of Mechanical Engineering department at S.R
Engineering college. He has 20 years of Teaching and
currently handling many research projects.
... Since the structure of SiO2 particles enacts a major aspect [16]. Incorporating different fillers like ATH (aluminium trihydrate), SiO2, Al2O3 (aluminium oxide), Si3N4 (silicon nitride), CaCO3 (calcium carbonate), CaSiO3 (wollastonite) enhanced the mechanical properties of the SR, higher crosslinking takes place owing to the chemical reaction between reinforcing particles and SR matrix, uniform distribution of the particles in the base material, effect of particle sizes of the micro & nanofillers, interaction between the molecules of filler and base polymer escalates [17][18][19][20][21][22][23][24][25]. Inclusion of large concentrations of optical fibre scrap as a filler in LSR/hardener composite evinced recommended results. ...
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... In addition to the previously mentioned qualities and its simplicity regarding fabrication and shaping, silicone rubber was adopted by various firms to produce a variety of products for the electronics industry, aviation industry, aerospace industry, bakeware industry, cookware industry, cable accessories industry, automotive industry, medical devices industry, veterinary industry, molding industry, semiconductors industry, and toy manufacturing industry [3]. Aluminium oxide (Al2O3) has several qualities, such as good strength, stiffness, outstanding dielectric qualities, improved heat conductivity, and wear resistance [4]. Cordierite ceramic is a magnesium aluminum silicate material with the general formula 2MgO. ...
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Full-text available
  • Jan 2002
Material samples of silicone rubber with known differences in their composition, i.e. different filler content and extra silicone oil added, have been aged at the Anneberg field station on the west coast of Sweden. ac or dc voltage supplied to cylindrical samples at stress levels of 50 or 100 V/mm. The work includes laboratory examination of material changes together with on-site, visual observations and leakage current measurements. Material samplings for the laboratory tests were made after 18 months of electrical aging, which went on for one more year in order to gather further information on the long-term electrical performance of the material. The dominant aging factor was the level of the applied stress, independent of ac or dc voltage. The dc stressed samples showed a higher leakage current and exhibited larger surface degradation compared with samples exposed to ac voltage. The material parameter, an addition of extra silicone oil, initially led to an increase in adhesion of pollutants, whereas the overall performance was improved by the higher suppression of the leakage current related to oligomer diffusion. Samples with lower levels of alumina trihydrate (ATH) exhibited a delayed onset of degradation, but once damaged they degraded more rapidly than the specimens with a higher ATH content. Infrared spectroscopy showed that the ATH was completely consumed at the eroded surface regions. The aging of the surfaces was further assessed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The low molar mass siloxanes present in the pollution layer were extracted and analyzed by size exclusion chromatography and gas chromatography-mass spectroscopy. The results indicated that the main degradation factor was thermal depolymerization activated by electrical discharges. Oxidative crosslinking of the silicone rubber, usually attributed to surface close corona discharges, appeared to have played a minor role
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Science and Technology of Rubber
Book
  • Jan 2005
The 3rd edition of The Science and Technology of Rubber provides a broad survey of elastomers with special emphasis on materials with a rubber-like elasticity. As in the 2nd edition, the emphasis remains on a unified treatment of the material; exploring topics from the chemical aspects such as elastomer synthesis and curing, through recent theoretical developments and characterization of equilibrium and dynamic properties, to the final applications of rubber, including tire engineering and manufacturing. Many advances have been made in polymer and elastomers research over the past ten years since the 2nd edition was published. Updated material stresses the continuous relationship between the ongoing research in synthesis, physics, structure and mechanics of rubber technology and industrial applications. Special attention is paid to recent advances in rubber-like elasticity theory and new processing techniques for elastomers. This new edition is comprised of 20% new material, including a new chapter on environmental issues and tire recycling.
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Hydrophobicity recovery of polydimethylsiloxane after exposure to corona discharges
Article
  • May 1998
  • POLYMER
A high-temperature-vulcanized polydimethylsiloxane (PDMS) elastomer has been subjected to corona discharges for different periods of time in dry air. The loss and recovery of hydrophobicity of the surface have been characterized by contact angle measurements. Immediately after exposure to corona discharges, samples showed a low surface hydrophobicity and, on storage in dry air, a continuous increase in hydrophobicity finally approaching the hydrophobicity of the unexposed material. The activation energy of the hydrophobicity recovery was two to four times greater than the activation energy of the diffusivity of low molar mass PDMS in PDMS elastomers, indicating that the diffusivity properties of the oxidized surface layer were different from that of the bulk. PDMS elastomers quenched in liquid nitrogen or subjected to small mechanical deformation (
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Characteristics of Electrical Insulation in PDMS-ATH Composite for High Voltage Insulators
Article
  • Jan 2008
The electrical insulation properties and the tracking and erosion resistances of high-temperature vulcanized silicone rubber were investigated as to the concentration of alumina trihydrate (ATH) therein for the fabrication of silicone rubber with optimum ATH content. Controlling the ATH concentration has been found to be an important factor in the enhancement of the tracking and erosion resistances of silicone rubber. In addition, the silicone rubber showed constant electrical resistivity and dielectric breakdown voltage without any decrease due to the interfacial problems with the addition of ATH to the silicone rubber. Therefore, this fabricated silicone rubber that contains an optimum ATH concentration can be applied to outdoor high-voltage insulators.
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Calcium and aluminium-based fillers as flame-retardant additives in silicone matrices. I. Blend preparation and thermal properties
Article
  • Sep 2010
  • POLYM DEGRAD STABIL
This series investigates silicone composites with enhanced thermal behaviour for cable applications. Calcium and aluminium-based fillers introduced into silicone formulations were classified according to three categories: non-hydrated fillers such as CaCO3 (precipitated calcium carbonate and natural calcite) and wollastonite, water-releasing fillers such as calcium hydroxide, ATH, boehmite, and hydroxyl-functionalized fillers including alumina and mica. The fillers were first characterized in detail, and the thermal stability of their blends with silicone was recorded by thermogravimetric analyses. A discussion on various aspects of the filler morphology (size, microstructure, release profile with temperature) on the silicone stability is finally given.
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History and bibliography of polymeric insulators for outdoor applications
Article
  • Feb 1993
A history of polymeric insulators is given, beginning in the 1940s when organic insulating materials were used to manufacture high-voltage indoor electrical insulators from epoxy resins. Their advantages and early experiences with them are given. A bibliography covering mainly 1970 to the present is given
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  • Jan 1998
  • 1043-1050
  • K G Princy
  • R Joseph
  • C S Kartha
Princy KG, Joseph R, Kartha CS (1998) Studies on conductive siliconerubbercompounds.JApplPolymSci69(5):1043-1050
  • Jan 2004
  • 348
  • Raji Sundararajan
  • Areef Muhammad
  • Noppom Chaipanit
  • Tim Karcher
  • Zhenquan Liu
Raji Sundararajan, Areef Muhammad, Noppom Chaipanit, Tim Karcher and Zhenquan Liu // IEEE trans on dielectric and electrical insulation 11 (2004) 348.
Results from long term tests with long rod composite insulators exposed to natural pollution
  • Jan 1984
  • E Sherif
  • C Andreasson
E Sherif and C. Andreasson, Results from long term tests with long rod composite insulators exposed to natural pollution (NordIS 84, 1984