Identification of swelling/shrinking coefficients under CO2 on an FKM O-ring – Comparison with HNBR and influence of reinforcements on the matrices

Abstract

A better understanding of elastomers’ behavior during Rapid Gas Decompression (RGD) requires advanced knowledge of what is happening during gas sorption and desorption. This will offer to improve numerical simulation phenomena to consider a real environmental use of an O-ring, as for thermal applications. A previous experimental study developed testing protocols to investigate the performance of elastomeric O-rings. The non-contact measurement technique has been validated to identify the swelling and shrinking coefficients during sorption and desorption of carbon dioxide (CO2) from a Hydrogenated Nitrile Butadiene Rubber (HNBR) O-ring. The present work describes the effect of CO2 pressures on Fluorocarbon rubber (FKM) seals behavior coupled with temperature. To evaluate the effect of reinforcing the HNBR and FKM matrices with nanofillers, experimental tests were carried out and compared with those of the two elastomers without fillers. The four materials’ CO2 sorption and desorption coefficients are identified, and their swelling upon decompression is measured. It appears that HNBR is the best candidate under the applied service conditions. On the other hand, the nanofillers introduced in the elastomers may cause some early damages under RGD conditions.