Permeation of nitrogen and oxygen gases through styrene–butadiene rubber, natural rubber and styrene–butadiene rubber/natural rubber blend membranes

New membranes based on styrene–butadiene rubber (SBR), natural rubber (NR) and SBR/NR blends were prepared for gas permeation studies. The effects of the nature and the degree of crosslinking in both SBR and SBR/NR blends on gas permeation behaviour were examined. The effects of blend composition and morphology on the gas permeation behaviour were also investigated. Theoretical models proposed by Maxwell, Bruggemen and Bottcher were used to investigate the relationship between morphology and permeation properties.