LAUSR

Abstract Carboxyl content in nitrile butadiene rubber (XNBR) has an impact on its application performance. However, its poor solubility makes it difficult to determine the carboxyl content in XNBR due to its high molecular weight. In the present work, olefin cross metathesis was used to degrade XNBR with acrylonitrile (AN) as chain transfer agent for the first time, to solve the solubility problem. After degradation under the optimized condition, with 2% AN and 0.2% catalyst at 60 °C for 30 min, the weight-average molecular weight (Mw) of the product decreased to 0.98 × 104 with distribution (Mw/Mn) of 3.83. Such product was easy to be dissolved, so the carboxyl content in XNBR could be determined with the routine titrimetric analysis methods.