The World's First Fluoroelastomer
Viton® fluoroelastomer is the most specified fluoroelastomer, well known for its excellent (400°F/200°C) heat resistance. Viton® offers excellent resistance to aggressive fuels and chemicals and has worldwide ISO 9000 and ISO/TS 16949 registration.
We've developed many types of Viton® to meet specific end-use and processing needs. There are differences between types of Viton® in terms of chemical resistance and mechanical properties.
Whether your application is automotive, chemical processing or any number of other industrial applications, there is a particular type of Viton® that best meets your specific performance requirements. The general purpose types differ primarily from the specialty types in chemical resistance. In the specialty family, the choice is among four types that are tailored for superior fluid resistance, low-temperature performance or combinations of these properties. In order to ensure product integrity and compliance to OSHA 1910.119 in finished parts made of Viton®, our seal helps guarantee that the parts you receive are made from 100% virgin Viton® from DuPont Performance Elastomers.
http://www.dupontelastomers.com/products/viton/viton.asp
Thursday, April 26, 2007
Silicone Rubber
Silicone rubber is a polymer that has a "backbone" of silicon-oxygen linkages, the same bond that is found in quartz, glass and sand. Normally, heat is required to vulcanise (set) the silicone rubber; this is normally carried out in a two stage process at the point of manufacture into the desired shape, and then in a prolonged post-cure process. It can also be injection molded.
[edit] Properties
Silicone rubber offers excellent resistance to extreme temperatures, being able to operate normally from minus 100°C to plus 500°C. In such conditions the tensile strength, elongation, tear strength and compression set can be far superior to conventional rubbers.
Silicone rubber has excellent high temperature properties. Organic rubber has a carbon to carbon backbone. This can leave them susceptible to ozone, UV, heat and other aging factors that silicone rubber can withstand well. This is why it is the material of choice in many extreme environments.
[edit] Specialist grades
There are also many specialist grades of silicone rubber that offer the following qualities: Steam resistance, metal detectable, glow in the dark, electrically conductive, chemical/oil/acid/gas resistance, low smoke emission and flame retardant.
[edit] Applications
Once milled and coloured the silicone rubber can be extruded into tubes, strips, solid cord or custom profiles within the size restrictions of the manufacturer. Cord can be joined to make "O" Rings and extruded profiles can also be joined to make up seals. Silicone Rubber can also be moulded into custom shapes and designs.
Retrieved from "http://en.wikipedia.org/wiki/Silicone_rubber"
Categories: Silicones Elastomers Sculpture materials
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SILICONE RUBBER PROPERTIES and SHELF LIFE
PDF]
Silicone Rubber
File Format: PDF/Adobe Acrobat - View as HTMLSuperior silicone tubing for medical, pharmaceutical and food applications ...... f) Storage & Shelf Life. Silicone compounds should be stored in a dry ...www.barloworld-scientific.com/internet/Download.nsf/directdownload/TALN6YTG28/$file/Esco%20Catalogue.pdf - Similar pages
SILICONE RUBBER PHARMA GRADE (21 CFR 177.2600)
go here
USP CLASS VI BIOLOGICAL COMPATIBILITY TESTS
go here
ASTM F2475-05 Standard Guide for Biocompatibility Evaluation of Medical Device Packaging Materials
can be purchased go here
bio compatibility testing at NORTHVIEW
go here
[edit] Properties
Silicone rubber offers excellent resistance to extreme temperatures, being able to operate normally from minus 100°C to plus 500°C. In such conditions the tensile strength, elongation, tear strength and compression set can be far superior to conventional rubbers.
Silicone rubber has excellent high temperature properties. Organic rubber has a carbon to carbon backbone. This can leave them susceptible to ozone, UV, heat and other aging factors that silicone rubber can withstand well. This is why it is the material of choice in many extreme environments.
[edit] Specialist grades
There are also many specialist grades of silicone rubber that offer the following qualities: Steam resistance, metal detectable, glow in the dark, electrically conductive, chemical/oil/acid/gas resistance, low smoke emission and flame retardant.
[edit] Applications
Once milled and coloured the silicone rubber can be extruded into tubes, strips, solid cord or custom profiles within the size restrictions of the manufacturer. Cord can be joined to make "O" Rings and extruded profiles can also be joined to make up seals. Silicone Rubber can also be moulded into custom shapes and designs.
Retrieved from "http://en.wikipedia.org/wiki/Silicone_rubber"
Categories: Silicones Elastomers Sculpture materials
Views
Article
Discussion
Edit this page
History
Personal tools
Sign in / create account
if (window.isMSIE55) fixalpha();
Navigation
Main page
Contents
Featured content
Current events
Random article
interaction
About Wikipedia
Community portal
Recent changes
Contact us
Make a donation
Help
Search
Toolbox
What links here
Related changes
Upload file
Special pages
Printable version
Permanent link
Cite this article
SILICONE RUBBER PROPERTIES and SHELF LIFE
PDF]
Silicone Rubber
File Format: PDF/Adobe Acrobat - View as HTMLSuperior silicone tubing for medical, pharmaceutical and food applications ...... f) Storage & Shelf Life. Silicone compounds should be stored in a dry ...www.barloworld-scientific.com/internet/Download.nsf/directdownload/TALN6YTG28/$file/Esco%20Catalogue.pdf - Similar pages
SILICONE RUBBER PHARMA GRADE (21 CFR 177.2600)
go here
USP CLASS VI BIOLOGICAL COMPATIBILITY TESTS
go here
ASTM F2475-05 Standard Guide for Biocompatibility Evaluation of Medical Device Packaging Materials
can be purchased go here
bio compatibility testing at NORTHVIEW
go here
Neoprene Rubber
Neoprene is a type of synthetic rubber. Neoprene rubber was developed in the 1930s. Since then, it has been incorporated into numerous products popular in daily life, from wetsuits to protective gear. Neoprene has a variety of properties that make it quite useful, including being abrasion-resistant, chemical-resistant, waterproof, somewhat stretchable and buoyant.
The many unique qualities of neoprene make it useful in a number of popular products. One of the most popular and visible uses of neoprene is with wetsuits. In wetsuits, neoprene traps water between the wetsuit and the wearer's skin. Body heat warms the water against the skin, which works to reduce heat loss from the body. This reduced heat loss allows someone to comfortably stay in colder water for a longer time. It can also be quite buoyant in the water. Many sports enthusiasts use neoprene wetsuits, including scuba divers, surfers and windsurfers.
Neoprene wetsuits come in a variety of thicknesses, from very thin one-half millimeter (about 1/16 inch) wetsuits used to prevent abrasions and sunburns in tropical water to thick seven millimeter (about 1/4 inch) wetsuits used in cold water. Not surprisingly, the thicker the neoprene in a wetsuit, the more insulating it is. While the black head-to-toe wetsuit commonly seen on television is the image many people have of neoprene wetsuits, they come in any number of colors, sizes and styles. Neoprene wetsuits can dramatically slow heat loss in the water, allowing wearers to remain the water for much longer than they would be able to without one.
Outside of the water, neoprene has a number of other uses. Neoprene is resistant to many chemicals and oil, making it particularly useful for protective gloves and similar articles. Neoprene is used in some situations where abrasion can be a problem as well. It can be found on a number of products today, including protective covers for items such as cellular telephones. It is also lightweight. The diverse uses of neoprene help to explain its popularity in many products.
The versatility of neoprene rubber have made it a popular material in a number of items. Its many insulating and protective properties have made neoprene a household name, incorporated into products as diverse as scuba-diving gear to protective gloves.
http://www.wisegeek.com/what-is-neoprene-rubber.htm
The many unique qualities of neoprene make it useful in a number of popular products. One of the most popular and visible uses of neoprene is with wetsuits. In wetsuits, neoprene traps water between the wetsuit and the wearer's skin. Body heat warms the water against the skin, which works to reduce heat loss from the body. This reduced heat loss allows someone to comfortably stay in colder water for a longer time. It can also be quite buoyant in the water. Many sports enthusiasts use neoprene wetsuits, including scuba divers, surfers and windsurfers.
Neoprene wetsuits come in a variety of thicknesses, from very thin one-half millimeter (about 1/16 inch) wetsuits used to prevent abrasions and sunburns in tropical water to thick seven millimeter (about 1/4 inch) wetsuits used in cold water. Not surprisingly, the thicker the neoprene in a wetsuit, the more insulating it is. While the black head-to-toe wetsuit commonly seen on television is the image many people have of neoprene wetsuits, they come in any number of colors, sizes and styles. Neoprene wetsuits can dramatically slow heat loss in the water, allowing wearers to remain the water for much longer than they would be able to without one.
Outside of the water, neoprene has a number of other uses. Neoprene is resistant to many chemicals and oil, making it particularly useful for protective gloves and similar articles. Neoprene is used in some situations where abrasion can be a problem as well. It can be found on a number of products today, including protective covers for items such as cellular telephones. It is also lightweight. The diverse uses of neoprene help to explain its popularity in many products.
The versatility of neoprene rubber have made it a popular material in a number of items. Its many insulating and protective properties have made neoprene a household name, incorporated into products as diverse as scuba-diving gear to protective gloves.
http://www.wisegeek.com/what-is-neoprene-rubber.htm
Nitrile Rubber
Nitrile rubber is a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. Some trade names are: Mill-Right N, Nipol, Krynac and Europrene.
Acrylonitrile butadiene rubber (NBR) is a family of unsaturated copolymers of 2-propenenitrile and various butadiene monomers (1,2-butadiene and 1,3-butadiene). Although its physical and chemical properties vary depending on the polymer’s composition of acrylonitrile (the more acrylonitrile within the polymer, the higher the resistance to oils but the lower the flexibility of the material), this form of synthetic rubber is generally resistant to oil, fuel, and other chemicals. Its resilience makes NBR the perfect material for disposable lab, cleaning, and examination gloves. In the automotive industry, it is used to make fuel and oil handling hoses, seals and grommets. NBR’s ability to withstand a range of temperatures from −40°C to +120°C makes it an ideal material for extreme automotive applications. Acrylonitrile butadiene is also used to create moulded goods, footwear, adhesives, sealants, sponge,expanded foams and floor mats. Compared to natural rubber, nitrile rubber is more resistant to oils and acids, but has inferior strength and flexibility. Nitrile rubber is generally resistant to aliphatic hydrocarbons. However (like natural rubber), it can be attacked by ozone, aromatic hydrocarbons, ketones, esters and aldehydes.
Contents[hide]
1 Production Process
2 Environmental Concerns
3 Misc
4 External links
//
[edit] Production Process
In the production of hot NBR, emulsifier (soap), 2-propenenitrile (acrylonitrile), various butadiene monomers (including 1,3-butadiene, 1,2-butadiene), radical generating activators, and a catalyst are added to polymerization vessels. Within the vessel, water serves as the reaction medium. The tanks are heated to 30°C-40°C to facilitate the polymerization reaction and to promote branch formation in the polymer. Because several monomers capable of propagation the reaction are involved in the production of nitrile rubber, the composition of each polymer can vary (depending on the concentrations of each monomer added to the polymerization tank and the conditions within the tank). One repeating unit found throughout the entire polymer may not exist. For this reason, there is also no IUPAC name for the general polymer. The reaction for one possible portion of the polymer is shown below:
1,3-butadiene + 1,3-butadiene + 2-propenenitrile + 1,3-butadiene + 1,2-butadiene → acrylonitrile butadiene rubber
Monomers are usually permitted to react for 5 to 12 hours. Polymerization is allowed to proceed to ~70% conversion before a “shortstop” agent (such as dimethyldithioarbamate and diethyl hydroxylamine) is added to react with the remaining free radicals. Once the resultant latex has “shortstopped”, the unreacted monomers are removed through a steam in a slurry stripper. Recovery of unreacted monomers is close to 100%. After monomer recovery, latex is sent through a series of filters to remove unwanted solids and then sent to the blending tanks where it is stabilized with an antioxidant. The yielded polymer latex is coagulated using calcium chloride, aluminum sulfate, and other coagulating agents in an aluminum tank. The coagulated substance is then washed and dried into crumb rubber.
The process for the production of cold NBR is very similar to that of hot NBR. Polymerization tanks are heated to 5 °C–15 °C instead of 30 °C–40 °C. Under lower temperature conditions, less branching will form on polymers (the amount of branching distinguished cold NBR from hot NBR).
[edit] Environmental Concerns
Acrylonitrile is considered an environmentally hazardous substance that cannot be freely ejected into the environment (it must be disposed through a rotary kiln, fluidized bed, liquid injection incineration, or underground injection). Because the compound is quite volatile and readily soluble in water, its release to the environment from waste sites is a concern. 1,3–butadiene is very reactive in the presence of hydroxyl radicals, and therefore possess high ozone creation potential. As mentioned previously, however, unreacted monomer recovery is nearly 100% in the process outlined above. Since unused monomers can easily be recycled, its disposal is not an unbearable concern. Thus, despite more stringent disposal restrictions, acrylonitrile butadiene rubber is produced throughout North America.
[edit] Misc
Because it is not crucial that every acrylonitrile butadiene polymer has one specific chemical structure (unlike polymers meant for ingestion, where small inconsistencies in chemical composition/structure have a pronounced effect on the body, the general properties of NBR are not altered by minor structural/compositional differences) quality control on its production is relatively lax. The production process itself is not overly complex; the polymerization, monomer recovery, and coagulation processes require some additives and equipment, but they are typical of the production of most rubbers. The necessary apparatus is simple and easy to obtain. For these reasons the substance is widely produced in poorer countries where labor is cheaper. Among the highest producers of NBR are Taiwan and China.
http://en.wikipedia.org/wiki/Nitrile_rubber
Acrylonitrile butadiene rubber (NBR) is a family of unsaturated copolymers of 2-propenenitrile and various butadiene monomers (1,2-butadiene and 1,3-butadiene). Although its physical and chemical properties vary depending on the polymer’s composition of acrylonitrile (the more acrylonitrile within the polymer, the higher the resistance to oils but the lower the flexibility of the material), this form of synthetic rubber is generally resistant to oil, fuel, and other chemicals. Its resilience makes NBR the perfect material for disposable lab, cleaning, and examination gloves. In the automotive industry, it is used to make fuel and oil handling hoses, seals and grommets. NBR’s ability to withstand a range of temperatures from −40°C to +120°C makes it an ideal material for extreme automotive applications. Acrylonitrile butadiene is also used to create moulded goods, footwear, adhesives, sealants, sponge,expanded foams and floor mats. Compared to natural rubber, nitrile rubber is more resistant to oils and acids, but has inferior strength and flexibility. Nitrile rubber is generally resistant to aliphatic hydrocarbons. However (like natural rubber), it can be attacked by ozone, aromatic hydrocarbons, ketones, esters and aldehydes.
Contents[hide]
1 Production Process
2 Environmental Concerns
3 Misc
4 External links
//
[edit] Production Process
In the production of hot NBR, emulsifier (soap), 2-propenenitrile (acrylonitrile), various butadiene monomers (including 1,3-butadiene, 1,2-butadiene), radical generating activators, and a catalyst are added to polymerization vessels. Within the vessel, water serves as the reaction medium. The tanks are heated to 30°C-40°C to facilitate the polymerization reaction and to promote branch formation in the polymer. Because several monomers capable of propagation the reaction are involved in the production of nitrile rubber, the composition of each polymer can vary (depending on the concentrations of each monomer added to the polymerization tank and the conditions within the tank). One repeating unit found throughout the entire polymer may not exist. For this reason, there is also no IUPAC name for the general polymer. The reaction for one possible portion of the polymer is shown below:
1,3-butadiene + 1,3-butadiene + 2-propenenitrile + 1,3-butadiene + 1,2-butadiene → acrylonitrile butadiene rubber
Monomers are usually permitted to react for 5 to 12 hours. Polymerization is allowed to proceed to ~70% conversion before a “shortstop” agent (such as dimethyldithioarbamate and diethyl hydroxylamine) is added to react with the remaining free radicals. Once the resultant latex has “shortstopped”, the unreacted monomers are removed through a steam in a slurry stripper. Recovery of unreacted monomers is close to 100%. After monomer recovery, latex is sent through a series of filters to remove unwanted solids and then sent to the blending tanks where it is stabilized with an antioxidant. The yielded polymer latex is coagulated using calcium chloride, aluminum sulfate, and other coagulating agents in an aluminum tank. The coagulated substance is then washed and dried into crumb rubber.
The process for the production of cold NBR is very similar to that of hot NBR. Polymerization tanks are heated to 5 °C–15 °C instead of 30 °C–40 °C. Under lower temperature conditions, less branching will form on polymers (the amount of branching distinguished cold NBR from hot NBR).
[edit] Environmental Concerns
Acrylonitrile is considered an environmentally hazardous substance that cannot be freely ejected into the environment (it must be disposed through a rotary kiln, fluidized bed, liquid injection incineration, or underground injection). Because the compound is quite volatile and readily soluble in water, its release to the environment from waste sites is a concern. 1,3–butadiene is very reactive in the presence of hydroxyl radicals, and therefore possess high ozone creation potential. As mentioned previously, however, unreacted monomer recovery is nearly 100% in the process outlined above. Since unused monomers can easily be recycled, its disposal is not an unbearable concern. Thus, despite more stringent disposal restrictions, acrylonitrile butadiene rubber is produced throughout North America.
[edit] Misc
Because it is not crucial that every acrylonitrile butadiene polymer has one specific chemical structure (unlike polymers meant for ingestion, where small inconsistencies in chemical composition/structure have a pronounced effect on the body, the general properties of NBR are not altered by minor structural/compositional differences) quality control on its production is relatively lax. The production process itself is not overly complex; the polymerization, monomer recovery, and coagulation processes require some additives and equipment, but they are typical of the production of most rubbers. The necessary apparatus is simple and easy to obtain. For these reasons the substance is widely produced in poorer countries where labor is cheaper. Among the highest producers of NBR are Taiwan and China.
http://en.wikipedia.org/wiki/Nitrile_rubber
EPDM Rubber
EPDM rubber (ethylene propylene diene monomer rubber) is an elastomer which is characterized by wide range of applications. EPDM rubber is used in automotive weather-stripping and seals, glass-run channel, radiator, garden and appliance hose, tubing, washers, belts, electrical insulation,as well as electrical insulation it is also used as a medium for water resistance in high voltage polymeric cable jointing installations, roofing membrane, geomembranes, rubber mechanical goods, plastic impact modification, thermoplastic, vulcanizates, motor oil additive, pond liner, electrical cable-jointing and chainmaille applications.
Satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and alkalis. Unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic hydrocarbons, halogenated solvents, and concentrated acids.
Mechanical Properties
Hardness, Shore A
40 - 90
Tensile Strength, Ultimate
17 MPa
Elongation at Break
600 %
Thermal Properties
CTE, linear 68°F
576 µm/m-°C
Maximum Service Temperature, Air
150 °C
Minimum Service Temperature, Air
-54 °C
Glass Temperature
-54 °C
[edit] External links
http://en.wikipedia.org/wiki/EPDM_rubber
Satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and alkalis. Unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic hydrocarbons, halogenated solvents, and concentrated acids.
Mechanical Properties
Hardness, Shore A
40 - 90
Tensile Strength, Ultimate
17 MPa
Elongation at Break
600 %
Thermal Properties
CTE, linear 68°F
576 µm/m-°C
Maximum Service Temperature, Air
150 °C
Minimum Service Temperature, Air
-54 °C
Glass Temperature
-54 °C
[edit] External links
http://en.wikipedia.org/wiki/EPDM_rubber
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