Use NBR Gaskets for Oil Resistance at its Best
Nitrile rubber is a synthetic rubber composed of a copolymer of butadiene and acrylonitrile. The amount of acrylonitrile determines the resistance and flexibility of the material. Most compositions will consist of 15 to 50 percent acrylonitrile. The increasing content of acrylonitrile lends higher strength, greater resistance to hydrocarbon oils, and lower permeability to gases to the compound, making these acrylonitrile-saturated compounds better suited for highly sensitive applications. The more acrylonitrile in the composition, however, also decreases the flexibility of the rubber because acrylonitrile possesses a higher glass transition temperature. This refers to the temperature below when molecules become stuck in a rigid, glassy state. This is due to the cross linking of molecular chains that occurs. When temperatures lower, segments cannot move as much. At a certain point, the molecule segments are completely frozen or stiff so that they cannot elongate without breaking. A hydrogenated version of NBR, also known as HNBR, is more resistant to low temperatures, remaining flexible, while also resisting thermal and oxidative deterioration. This is important because NBR is most susceptible to atmospheric molecules, such as ozone or ketone molecules.
General Uses: Many medical professions use NBR sealing to keep their expensive and acutely sensitive equipment tools safe and untainted by common outdoor molecules. Like many rubbers, however, nitrile gasket material becomes less flexible at lower temperatures as the molecules become locked in the glassy state mentioned before.
4.Rubber Mats in Kitchens