Butadiene NBR is introduced in detail

production

Emulsifiers, 2-acrylonitrile, various butadiene monomers (including 1, 3-butadiene, 1, 2-butadiene), initiators, and catalysts are added to the polymerization containers in the process of producing hot nitrile rubber.Water ACTS as a medium in the reaction vessel, which is heated to 30-40℃ to facilitate polymerization and facilitate the formation of side chains.Because a variety of monomers that can participate in the addition polymerization reaction are added in the production, the final types of polymers will also change with the change of the concentration of each monomer or the change of the reaction conditions, and the types of polymers are also complex.It is impossible to find simple repeating units in the final product.For this reason, nitrile butadiene rubber, as a general polymer, does not have a formal IUPAC name.Part of the polymerization reaction can be expressed by the following equation: 1, 3-butadiene +1, 3-butadiene + 2-acrylonitrile +1, 3-butadiene +1, 3-butadiene → nitrile butadiene

Polymerization usually takes 5-12 hours and yields up to 70%. As the reaction approaches its end, a chain terminator (e.g., dimethyl dithiocarbonate and diethylhydroxylamine) is added to the container to react with the remaining free radicals, thereby terminating the polymerization.The unreactive monomer is removed by means of a mud gas extractor.

The process of producing cold nitrile butadiene rubber is very similar to that of hot nitrile butadiene rubber. The polymerization reaction vessel is heated to 5-15℃ instead of 30-40℃.At lower temperatures, the number of branched chains in the polymer can be greatly reduced.The biggest difference between cold and hot NBR is the number of branch chains.

The nature of the

NBR has a elongation of 300% and tensile strength of 10N/mm2.Nitrile butadiene rubber has good tolerance to mineral oil, vegetable oil, benzene, gasoline, dilute acid and alkali.However, NBR lip seals should not be used at temperatures higher than 80℃, where NBR stability to solvent decreases.

application

Nitrile butadiene rubber USES include disposable medical gloves, conveyor belts, hoses, o-rings, gaskets, oil seal products, v-belts, synthetic leather, printing rollers, and cable sheaths.Nitrile butadiene rubber is also used to make adhesives.The hydrogenated version of nitrile butadiene rubber (HNBR) is often used to make o-rings for air conditioning.

security

It is dangerous to wear NBR when operating strong oxidants such as nitric acid. NBR can be oxidized in contact with oxidizing agents and even cause combustion.