Nitrile rubber is a copolymer of butadiene and acrylonitrile in which the unsaturated diene segments form the elastomeric network and the nitrile groups supply polarity [1]. The acrylonitrile fraction, usually between 18 and 50 percent, sets the balance: higher content raises oil resistance and the glass transition temperature, while lower content preserves flexibility in the cold [1]. Vulcanisation proceeds through the residual double bonds, and the resulting crosslink density fixes compression set and swelling [2]. Hydrogenated grades convert backbone double bonds into methylene sequences, which removes the sites at which oxidation and ozonolysis begin [3]. The nitrile dipole also makes the polymer compatible with polar plasticisers and incompatible with non-polar oils [1].
- nbr elastomer
- acrylonitrile content
- hydrogenated nitrile rubber
- oil resistance
- vulcanisation
References
- Verdier, N.; Lepage, D.; Prébé, A.; Aymé‐Perrot, D.; Dollé, M.; Rochefort, D.; Crosslinker free thermally induced crosslinking of hydrogenated nitrile butadiene rubber. Journal of Polymer Science Part A: Polymer Chemistry 2018, 56, 1825-1833, 10.1002/pola.29063.
- Alcock, B.; Olafsen, K.; Huse, J.; Grytten, F.; The low temperature crystallization of hydrogenated nitrile butadiene rubber (HNBR). Polymer Testing 2018, 66, 228-234, 10.1016/j.polymertesting.2017.12.027.
- Wang, H.; Yang, L.; Rempel, G.L.; Homogeneous Hydrogenation Art of Nitrile Butadiene Rubber: A Review. Polymer Reviews 2013, 53, 192-239, 10.1080/15583724.2013.776586.