Determination of Acrylonitrile Content in Nitrile Butadiene Rubber Vulcanizates by Py-GCMS Techniques

Nitrile Butadiene Rubber (NBR), a copolymer of butadiene and acrylonitrile is known for its superior resistance to hydrocarbon oil, low gas permeability and excellent thermal stability. It is extensively used in seals, O-rings, conveyor belts and pneumatic tires. It is worth mentioning that these performance attributes are predominantly influenced by acrylonitrile content. While solid-state 13C Nuclear Magnetic Resonance (NMR) is an established technique for structural characterization of rubber vulcanizates, its high cost and accessibility limits its application in routine industrial analysis. This study aims to develop Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GCMS) as a robust, precise, cost-effective alternative to determine acrylonitrile content in NBR vulcanizates. This research demonstrates and establish a method to determine the acrylonitrile (ACN) content in finished rubber vulcanizates through pyrolysis gas chromatography-mass spectrometry (Py-GCMS). This method illustrates the precise measurement of ACN content and validated through 13C nuclear magnetic resonance (NMR) spectroscopy while it is in the range of 18% to 53%. Py-GCMS is applied to identify the pyrolytic fragments that aid in quantification in finished rubber products. This approach provides a comprehensive framework for optimizing NBR formulations tailored to specific performance requirements.