# The permeability coefficient of a type of small gas molecule

# The permeability coefficient of a type of small gas molecule

The permeability coefficient of a type of small gas molecule in a polymer is dependent on absolute temperature according to the following equation:

where and Qp are constants for a given gas-polymer pair. Consider the diffusion of hydrogen through a poly (dimethyl siloxane) (PDMSO) sheet 20 mm thick. The hydrogen pressures at the two faces are 10 kPa and 1 kPa, which are maintained constant. Compute the diffusion flux [in (cm3 STP)/cm2 âs] at 350 K. For this diffusion system

Qp = 13.7 kJ/mol

Also, assume a condition of steady state diffusion