HYGROPHOTOGRAPHIC STUDIES ON THE PERMEABILITY OF PACKAGING MATERIALS TO WATER AND MOISTURE
Final rept., 31 Jan 1962-31 Jan 1963
INSTITUT PASTEUR PARIS (FRANCE)
Pagination or Media Count:
The experiments at normal temperature were carried out by plunging a part of the preparations into liquid water contained in a desiccator and placing the other part on a support placed above in the atmosphere saturated by steam which covers the liquid. Difficulties were encountered in the preparation of bags by means of Tedlar and Saran films it was impossible to obtain a vacuum by soldering with a flame. Accordingly, the experiments were carried out at normal atmospheric pressure. For the plastics which are sufficiently permeable to water, great differences were not noticed between the permeability to water and to steam in the zone of weak temperatures, differences which became less and less sensitive in proportion as temperature was increased. The two permeabilities became practically equal at the temperatures of 85 and 95 C Tedlar and Profax, except for the Saran whose permeability to steam in this same zone of temperatures is clearly revealed less elevated than the permeability to water, due probably to the profound modification undergone by the film at the contact of hot water. In the case of FEP, the differences of the two values remained constant, while for the plastic materials of low permeability to water, as the Kel-F, no difference was verified, their permeability to water being the same as their permeability to water vapor for all the temperatures studied.
- Containers and Packaging