Rubbery polymers, membranes

Rubbery polymer membrane materials have the ability to permeate preferentially condensable vapors. Rubbery membranes were found to be very profitable for the recovery of high-value monomer in petrochemical plants purges gases (Table 6.12). ° ° In the case of large polymerization facilities, the value of purge monomers can reach amounts up to 2 million USD per year. 

Membrane Teehnology Researeh (MTR) has taken the lead in the development of organic vapor selective rubbery polymer membranes. These membranes offer mixed gas propane to methane selectivity of 3-5 and butane to methane seleetivity of 5-10. The actual selectivity, however, also depends on... 

Four kinds of membranes are used to effect gas separations rubbery polymers, glassy polymers, porous membranes, and membranes capable of capillary condensation. Rubbery polymer membranes can be single polymers or copolymers. Their behavior is essentially that of a viscous liquid. Gas molecules diffusing in these membranes tend to have diffusion coefficients of the order of 10 cm /sec. Any selectivity in these membranes tends to come from differences in the partition coefficients. 

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