The Effect of Compression on Permeation of Hydrocarbons through Dimethyl and Fluorosilicone Rubber

This paper provides a quantitative measurement of the reduction of permeation of hydrocarbons through Dimethyl (VMQ) and Fluorosilicone rubber (FVMQ) as a function of the degree of compression. Permeation testing was performed on five formulations at various compression levels. Finite element analysis (FEA) was utilized to relate the total hydrocarbon loss to the stress state in the gasket (specifically the hydrostatic pressure). It is expected that this relationship will be used to assist in the design and evaluation of the performance of a variety of gasket configurations. Interestingly, even moderate compression levels greatly enhanced the permeation resistance of the seals. Basing material selection for permeation resistance only on flat disk permeation cup data may be inappropriate. Ideally this new information will assist the seal designer to find ways to optimize the permeation performance of the gasket without the need to resort to testing every design option.