Study of the Climatic Stability of the Elastomer Based on a Mixture of Nitrile-butadiene, Butadiene, and Isoprene Rubbers in a Petroleum Environment

Abstract

An elastomeric material was developed based on a rubber mixture using a methodology that includes predicting phase morphology, choosing a technological process to regulate phase morphology, and studying performance during full-scale tests. The developed elastomer for sealing purposes, based on mixtures of nitrile-butadiene (BNKS-18), butadiene (SKD-L), and isoprene (SKI-3) rubbers, was exposed to the climatic conditions of the Republic of Sakha (Yakutia) in an oil environment. During the test, physical and mechanical properties, compression set, swelling degree, frost resistance coefficient (KV) at –50 °C, and plasticizer content were measured. Critical changes in the main properties did not appear during the one-year experiment, despite a slight decrease in tensile strength (by 22 %) and compression set (by 20 %) at the beginning of the exposure. However, due to the complete washout of the plasticizer, the KV decreased (by 70 %). The residual KV value was 0,13, while for industrial rubber based on individual BNKS-18 it was approximately 0. The low-temperature elasticity of the material can be explained by the presence of the SKD-L and SKI-3 rubbers, which cannot be washed out.