Silicone Rubber, Its Development and Technological Progress

1988 ◽  
Vol 61 (3) ◽  
pp. 470-502 ◽  
Author(s):  
Keith E. Polmanteer
Keyword(s):  
Silicone Rubber ◽  
Technological Progress ◽  
Main Chain ◽  
Backbone Flexibility ◽  
Commercial Development ◽  
Silicone Polymers ◽  
Chronological Sequence ◽  
Group Rotation ◽  
Molecular Forces ◽  
Silicone Rubbers

Abstract This paper has described silicone rubber, its first commercial development in 1944, and its technological progress since then. Pioneering research on silicon opened the door to the development of silicone polymers and silicone rubber. The substitution of two methyl groups on silicon was present in the first examples of silicone rubber and still is the predominant organic group in commercial silicone rubber today. Silicone rubbers have filled a need in the marketplace because of their combination of unusual properties not found in other rubbers. The alternating inorganic main-chain atoms of silicon and oxygen, and the two pendant organic groups, primarily methyl, provide strong chain bonds, backbone flexibility, ease of side-group rotation, and low “inter” and “intra” molecular forces. This molecular makeup and properties thereof are primarily responsible for the observed performance of silicone rubbers. Many significant advances in silicone rubber have been discussed in chronological sequence to trace its history from 1944 to 1987.

Network Scission Processes in Peroxide Cured Methylvinyl Silicone Rubber

1967 ◽  
Vol 40 (2) ◽  
pp. 629-634
Author(s):  
D. K. Thomas
Keyword(s):  
Silicone Rubber ◽  
Elevated Temperatures ◽  
Main Chain ◽  
Methyl Groups ◽  
Chain Polymer ◽  
Filled Rubber ◽  
Oxidative Reactions ◽  
Silica Filler ◽  
Silicone Rubbers ◽  
Hydrolysis Of

Abstract In what appeared to be a complex system it transpires that network scission in methylvinyl silicone rubbers at temperatures below 250° C is due largely to hydrolytic reactions in the main chain polymer. At temperatures of 250° C and above there are indications that a significant amount of scission arises from oxidative reactions in the crosslinks, and that this reaction is catalyzed by acidic residues in the rubber. There is no indication that acidic byproducts of the vulcanization reaction catalyze the hydrolysis of siloxane bonds in the polymer. In conventional heat aging tests in which the rubber remains in an unstrained condition the effects of hydrolysis will only be observed if the concentration of water in the system is allowed to rise. Under these circumstances softening will occur because of a shift in the position of equilibrium in the reaction ∼Si—O—Si—O∼ + H2O→∼Si—OH+ HO—Si—O∼ On aging the material in a well ventilated situation the effects of hydrolysis are not seen and the silicone rubber becomes brittle after long exposure at high temperature. This embrittlement must result from additional crosslinking caused by oxidative reactions in the methyl groups of the main chain polymer. When the rubber is used in compression or tension, hydrolytic scission will affect performance, and in applications of this sort it is important to dry the rubber before use and prevent access of moisture to the component during use. With filled rubber the silica filler is a further source of moisture and drying needs to be carried out at elevated temperatures immediately before use. In order to improve the confined heat aging performance of silicone rubber an alternative filler to fine silica is needed which does not have the same affinity for water. It may be, however, that ability to reinforce silicone rubber and affinity for water are inseparable.

scholarly journals DC inline plane test of silicone rubber samples with different filler for high-voltage insulation

2020 ◽  
Vol 18 (2) ◽  
pp. 607
Author(s):  
Nurbahirah Norddin ◽  
Intan Mastura Saadon ◽  
Najwa Kamarudin ◽  
Norain Rahim ◽  
Jeefferie bin Abd Razak
Keyword(s):  
Calcium Carbonate ◽  
High Voltage ◽  
Silicone Rubber ◽  
Hot Press ◽  
Rubber Composites ◽  
High Voltage Insulation ◽  
Internal Mixer ◽  
Silicone Rubbers ◽  
Material Preparation ◽  
Inclined Plane Test

<span>This paper is about preparation of silicone rubber (SiR) samples with different filler for high-voltage insulation purpose. The fillers used were silica from waste glass, calcium carbonate from cockle shell, silica/calcium carbonate and wollastonite. All the fillers were crushed into powder and undergo internal mixer and hot press as a material preparation. It was expected that the combination of filler with silicone rubber would give better result when experiencing ageing process. The direct current (DC) inclined plane test was used to investigate the tracking and erosion on silicone rubber composites. The tracking length was observed between the top and bottom electrode. Comparison would then be made between the silicone rubbers with different fillers based on the result obtained from the experiment.</span>

Structural Control and Property Development of Silicone Polymers

2018 ◽  
Vol 45 (3) ◽  
pp. 129-136
Author(s):  
Hiroki Uehara ◽  
Takeshi Yamanobe ◽  
Eiichi Akiyama
Keyword(s):  
Structural Control ◽  
Main Chain ◽  
Tensile Modulus ◽  
Industrial Applications ◽  
Silicone Elastomer ◽  
Property Development ◽  
Blend Films ◽  
Dimethyl Siloxane ◽  
Silicone Polymers ◽  
Phenyl Rings

Typical silicones, including poly(dimethyl siloxane) (PDMS), are amorphous, but poly(tetramethyl-p-silphenylene-siloxane) (PTMPS) containing phenyl rings in the main chain is crystalline. A combination of in-situ X-ray and NMR measurements during heating of PTMPS indicates that the molecular motion of the phenyl rings exhibits remarkable anisotropy even in the molten state, suggesting rigidity of the PTMPS molecules. Therefore, a melt-drawing technique could be successfully applied to PTMPS. The obtained melt-drawn PTMPS membrane is transparent but exhibits an excellent tensile modulus and strength of 1.7 GPa and 20 MPa, which are enough for various industrial applications. Similar introduction of phenyl rings in the main chain is also effective for property development of silicone elastomer. Blend films of PTMPS and silicone elastomer exhibits the characteristic phase separation, depending on the blending compositions. Such blend films give the remarkably higher tensile strength than the original silicone elastomer, due to the crystalline component.

scholarly journals Compatibility Study of Silicone Rubber and Mineral Oil

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5899
Author(s):  
Smitha Karambar ◽  
Stefan Tenbohlen
Keyword(s):  
Dielectric Properties ◽  
Moisture Content ◽  
Silicone Rubber ◽  
Mineral Oil ◽  
Acid Number ◽  
Compatibility Study ◽  
Total Acid ◽  
Silicone Rubbers ◽  
Conductive Silicone Rubber ◽  
Solid Insulation

In this study, three types of silicone rubbers, namely, insulative silicone rubber, conductive silicone rubber and silicone rubber with conductive as well as insulative layers are investigated for their compatibility with mineral oil. Mineral oil with different silicone rubber samples is thermally aged at 130 °C for 360 h, 720 h and 1080 h and at 23 °C, 98 °C and 130 °C for 360 h. At the end of each ageing interval, mineral oil and oil-impregnated silicone rubbers are investigated for their dielectric properties. Aged mineral oil samples are investigated for their moisture content, breakdown voltage, colour number, dissolved gases and total acid number, whereas solid insulation samples are investigated for their moisture content. Additionally, pressboard samples in mineral oil and mineral oil without any solid insulation materials are also aged under the same conditions and are investigated for their dielectric properties. From the obtained results, it can be assessed that the presence of carbon particles in conductive silicone rubber negatively impacts the dielectric properties of mineral oil. Among the investigated silicone rubbers, the insulative silicone rubber exhibits good compatibility with mineral oil and a strong potential for being used in mineral oil.

scholarly journals Research on the electric field intensity distribution of high-voltage cable terminal improved by non-linear material

2021 ◽  
Vol 8 ◽  
pp. 23
Author(s):  
Guowei Li ◽  
Yong Wang ◽  
Xuexia Xu
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
High Voltage ◽  
Silicone Rubber ◽  
Internal Field ◽  
Field Distortion ◽  
Non Linear ◽  
Calculation Results ◽  
Linear Material ◽  
Silicone Rubbers

The electric field distortion caused by the high voltage current environment in the cable terminal will greatly increase the failure probability and reduce the operation safety; therefore, it is necessary to ensure the uniform distribution of the electric field in the terminal. This paper briefly introduced the high-voltage cable terminal and non-linear materials. The traditional silicone rubber and the silicone rubber added with nano-SiO2 were prepared. The electrical conductivity of the two silicone rubbers was tested, and the electric field of the cable terminal was simulated. The results demonstrated that the nano-SiO2 improved silicone rubber had a higher non-linear conductivity and was less affected by temperature. The calculation results of the simulation model also showed that the distribution of the internal field strength was more uniform, and the maximum field strength on the reinforced insulation was smaller after the improved silicone rubber was used as the reinforced insulation.

scholarly journals SEMI-ACTIVE DAMPING PERFORMANCE OF IRON PARTICLE FILLED SILICONE RUBBER

2016 ◽  
Vol 3 ◽  
pp. 7-10 ◽  
Author(s):  
Florian Dirisamer ◽  
Umut Cakmak ◽  
Edmund Marth ◽  
Zoltan Major
Keyword(s):  
Magnetic Field ◽  
Silicone Rubber ◽  
Field Effect ◽  
Iron Particle ◽  
Active Damping ◽  
Damping Coefficient ◽  
Silicone Elastomers ◽  
Silicone Rubbers

The aim of this work was to design, produce and evaluate a demonstrator to visualize the magneto-induced damping behaviour of materials. In contrast to standard materials, the damping coefficient of iron particle filled silicone rubbers can be controlled by a semi-active magnetic field. This field effect should be characterized in order to evaluate the suitability of these magnetorheological silicone elastomers for the use in different configurations and applications.

Solution and Diffusion in Silicone Rubber. II. Influence of Fillers

1963 ◽  
Vol 36 (3) ◽  
pp. 651-659 ◽  
Author(s):  
R. M. Barrer ◽  
J. A. Barrie ◽  
N. K. Raman
Keyword(s):  
Silicone Rubber ◽  
Porous Silica ◽  
Reference Models ◽  
Silica Filler ◽  
High Area ◽  
Silicone Rubbers ◽  
And Diffusion

Abstract An investigation has been made of the effect of a high area silica filler upon the solubility and diffusion of some C4 and C5 paraffins in silicone rubbers. The membranes studied contained by weight 0, 10, 20, 30 and 40 parts of filler per 100 parts of polymer. The solubilities have been discussed in terms of two reference models: the first in which silica and rubber phases act independently as sorbents; and the second in which the filler is regarded as completely wetted by polymer and is thus a non-sorbent. Diffusion and permeation have also been considered in terms of the models, assuming with the first model an immobile sorbed layer on the porous silica. It has been found that, although some aspects of the behavior can be explained, the results are not fully in agreement with either model, and that the behavior of the heterogenous membrane is complex.

scholarly journals Fluorosilicone as an Omnimold for Microreplication

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 406 ◽  
Author(s):  
Teng Zhang ◽  
Xiaokui Yue ◽  
Dan Sameoto
Keyword(s):  
Silicone Rubber ◽  
Soft Lithography ◽  
Mold Material ◽  
Material Compatibility ◽  
Thermosetting Polymers ◽  
Molded Parts ◽  
New Material ◽  
Multiple Materials ◽  
Silicone Rubbers ◽  
Micro Structures

Soft lithography and replica molding have been an integral part of polymer basic microfabrication for over 20 years. The use of silicone rubber materials as either molds or directly molded parts are well described in the literature and have provided researchers with an easily accessible technique to reproduce complex micro and nanostructures with minimal costs and technical challenges. Yet, for many applications, the use of standard silicones may not necessarily be the best choice, either as a mold material or as a replicated surface. For those instances where a mold is required that is high temperature tolerant, flexible, durable and capable of being used as a mold for multiple materials including silicone rubber, the most commonly used silicone rubber, Sylgard-184, has substantial deficiencies. In this work, we introduce a new material, Fluorosilicone that has not been described in the microfabrication field in detail and determine it is capable of reproducing micro structures via soft lithography techniques and being used as a mold for thermoplastic and thermosetting polymers, including silicone rubbers. Material compatibility, appropriate processing conditions for quality replicas and demonstration of extremely fast production of silicone microstructures are reported.

Modeling processing of silicone rubber: Liquid versus hard silicone rubbers

2010 ◽  
Vol 119 (3) ◽  
pp. 1864-1871 ◽  
Author(s):  
Juan P. Hernández-Ortiz ◽  
Tim A. Osswald
Keyword(s):  
Silicone Rubber ◽  
Silicone Rubbers
Sign in / Sign up

Export Citation Format

Share Document