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.

Evaluation of elastomer suitability for CCUS: Chemical compatibility and rapid gas decompression in supercritical CO2

“…The reduced swelling and hardness changes of HNBR, observed in Section 3.1 of this work, can be attributed to the hydrogen‐saturated structure of HNBR having less interaction with CO 2 molecules, as well as the high crosslink density and carbon black reinforcement of the HNBR material 40 …”

“…The reduced swelling and hardness changes of HNBR, observed in Section 3.1 of this work, can be attributed to the hydrogen-saturated structure of HNBR having less interaction with CO 2 molecules, as well as the high crosslink density and carbon black reinforcement of the HNBR material. 40 In summary, the ATR-FTIR technique only indicates the presence of additive leaching on the surface. Since the primary chains of elastomers remain chemically unaltered after sCO 2 aging, the FTIR analysis does not reflect any changes in the mechanical properties of the bulk elastomers.…”

Phase behavior of rubber and supercritical CO2: Operating parameters and swelling characteristics

“…23 Lainé et al determined the swelling and shrinking coefficients of a fluoroelastomer O-ring in subcritical CO 2 and found that pressure changes had minimal effect on the swelling ratio, while temperature exhibited a significant influence. 24 General-purpose rubbers, such as styrene-butadiene rubber (SBR), natural rubber (NR), 1,4-cis polybutadiene rubber (BR), and polyisoprene (IR), are widely used for fabricating rubber foam their low cost and excellent mechanical properties, particularly resistance to abrasion. 25 Lemert et al investigated the swelling of IR in ScCO 2 and observed a linear relationship between swelling degree and pressure by extrapolating data from a series of styrene-isoprene copolymers.…”

“…Shevtsova et al reported on the permeation of ScCO 2 into perfluoroelastomers and demonstrated that the molar fluxes of the samples remained independent of pressure when the pressure exceeded 12 MPa 23 . Lainé et al determined the swelling and shrinking coefficients of a fluoroelastomer O‐ring in subcritical CO 2 and found that pressure changes had minimal effect on the swelling ratio, while temperature exhibited a significant influence 24 . General‐purpose rubbers, such as styrene‐butadiene rubber (SBR), natural rubber (NR), 1,4‐cis polybutadiene rubber (BR), and polyisoprene (IR), are widely used for fabricating rubber foam their low cost and excellent mechanical properties, particularly resistance to abrasion 25 .…”