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Nitrile rubber is a synthetic rubber co-polymer of acrylonitrile (ACN) and butadiene. Some trade names are: Nipol, Krynac and Europrene. coming from latex is mostly polymerized isoprene with a small percentage of impurities in it. ...
Polymer is a generic term used to describe a very long molecule consisting of structural units and repeating units connected by covalent chemical bonds. ...
Acrylonitrile (CH2=CH-C≡N), is a pungent smelling, extremely flammable organic liquid. ...
Butadiene can refer to either one of two hydrocarbon chemical compounds which are alkenes that are isomers of each other. ...
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, 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. Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically. ...
Natural olive oil Synthetic motor oil Oil is a generic term for a chemical compound that is not miscible with water, and is in its liquid state at common ambient temperatures. ...
It has been suggested that strong acid be merged into this article or section. ...
In chemistry, aliphatic compounds are non-aromatic organic compounds, in which carbon atoms are joined together in straight or branched chains rather than in rings. ...
For other uses, see Ozone (disambiguation). ...
In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ...
Hydrocarbons are refined at oil refineries and processed at chemical plants In chemistry, a hydrocarbon is any chemical compound that consists only of the elements carbon (C) and hydrogen (H). ...
Ketone group A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a chemical compound that contains this functional group. ...
General formula of an ester of a carboxylic acid. ...
An aldehyde is either a functional group consisting of a terminal carbonyl group or a compound containing a terminal carbonyl group. ...
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 to 40°C. Under lower temperature conditions, less branching will form on polymers (the amount of branching distinguished cold NBR from hot NBR).
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.
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.
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