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A transient method of measuring the water vapour permeability of packaging films I. Dynamic performance of a sorptive sensor
Author(s) -
Doroszewicz Stefan
Publication year - 1996
Publication title -
packaging technology and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 50
eISSN - 1099-1522
pISSN - 0894-3214
DOI - 10.1002/(sici)1099-1522(199601)9:1<43::aid-pts52>3.0.co;2-q
Subject(s) - materials science , relative humidity , permeability (electromagnetism) , permeation , inertia , water vapor , transient (computer programming) , humidity , exponential function , analytical chemistry (journal) , chemistry , thermodynamics , chromatography , membrane , mathematics , physics , organic chemistry , classical mechanics , mathematical analysis , biochemistry , computer science , operating system
Principles of an analysis of the inertia of a sorptive sensor used for transient measurements of water vapour permeability through packaging films have been developed. The construction of the measuring cell and the method of measurement of water vapour permeation through packaging films have been readjusted to the developed principles. It is shown that the inertia of a sorptive sensor, defined as a difference Δ between measured signal value RH* and an estimated value of air relative humidity RH 1 close to the film surface in an input chamber can be described as a difference of exponential functions Δ = RH 0 ·[exp(−Aτ) − exp(−Bτ)]. The characteristic parameter determining the sensor inertia is the maximum delay time τ m ; the roots of the function Δ(τ) derivative. The theory and procedure for using τ m for the iterative determination of water vapour permeability through packaging films based on analysis of the sorptive sensor inertia is presented.