Acrylonitrile/butadiene copolymer

Chemical properties

NBR is important for its high oil and temperature resistance. Flexibility at very low temperatures is obtained with lower acrylonitrile content: in turn, this sacrifices some oil resistance. Low-temperature flexibility for some applications can be modified by plasticizers or blends. Additional properties include resistance to heat, abrasion, and water, as well as resistance to gas permeation. NBR is frequently plasticized with organic phosphate, phthalic ester, or dibenzyl ether.

The Uses of Acrylonitrile/butadiene copolymer

Applications include fuel lines, hoses, automobile parts, structural adhesives, oil-resistant clothing or articles, gloves, and shoe soles and heels. Gloves made of nitrile rubber are comparable to neoprene gloves in their resistance to organic solvents; nitrile rubber gloves were superior in resistance to II-hexane and inferior in resistance to phenol. NBR is used for hoses, gaskets, and protective clothing.

Production Methods

NBR is produced by polymerization of acrylonitrile and butadiene in varying proportions. The basic steps are the emulsion polymerization techniques used for styrene– butadiene. The process yields both “hot” and “cold” rubber. Hot rubbers are branched and contain some cross-linked gel. The more linear cold rubbers are slightly cross-linked by incorporating divinyl benzene to improve processability and compression set resistance.