Units of gas permeability constants

摘要

AbstractGas permeability constants of polymers are generally expressed by composite units which containdocumentclass{article}pagestyle{empty}begin{document}$$ frac{{left( {{rm amount of gas}} right)left( {{rm thickness of membrane}} right)}}{{left( {{rm membrane area}} right)left( {{rm time}} right)left( {{rm differential pressure of gas}} right)}}. $$end{document}Numerous combinations of various units to express each component units are used. However, permeability constants of nongaseous substances in polymer membranes are generally expressed by the units of cm2/sec, which are identical to the units of the diffusion constant. The relationship between constants in units of cm2/sec and conventional composite units for gas permeability constants is presented, and the advantage of using the units in cm2/sec to express gas permeability constants is discussed.