4.1 Hydrogenated nitrile rubbers are available at different levels of unsaturation and different acrylonitrile content. Highly saturated grades offer optimum resistance to aging, such as exposure to heat, ozone, and chemicals, and can be effectively cured only with peroxides or high energy radiation.

4.2 Partially unsaturated grades can be cured by sulfur systems in addition to peroxides and high energy radiation.

4.3 This test method provides an infrared technique to determine the unsaturation level of hydrogenated nitrile rubbers in the raw state. It can be used for research and development, quality control, and referee purposes.

1.1 This test method covers the percentage of residual unsaturation (double bonds in unhydrogenated butadiene) in hydrogenated nitrile rubber and is based on infrared examination of rubber films cast from solution.

1.2 This test method is applicable to all grades of hydrogenated nitrile rubber in the raw state.

1.3 This test method assumes that specimens and infrared spectra are prepared and analyzed by experienced personnel and that the equipment is operated according to the manufacturer's direction for optimum performance. No details for operation of infrared spectrophotometers are included in this test method.

1.4 Since it is customary in infrared spectrophotometry to use wavenumbers (cm⁻¹) rather than Hertz (Hz), the unit for frequency in the SI system, the former is employed throughout this test method.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.