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Humidity regulation by stretched PP and PLA films with dispersed CaCl 2
Author(s) -
Sängerlaub Sven,
Miesbauer Oliver,
Michael Linda,
Müller Kajetan,
Stramm Cornelia,
Pecyna Marek,
Langowski HorstChristian
Publication year - 2018
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.45713
Subject(s) - water vapor , polypropylene , sorption , relative humidity , materials science , diffusion , polymer , desorption , chemical engineering , polylactic acid , permeation , humidity , absorption (acoustics) , polymer chemistry , absorption of water , chloride , composite material , adsorption , chemistry , organic chemistry , thermodynamics , biochemistry , physics , membrane , engineering , metallurgy
Polymer materials that regulate the relative humidity in their environment are relevant for applications in the packaging and building sectors. By integration of salts in polymer structures, such materials are able to absorb and desorb high amounts of water vapor. In this study, films of polylactic acid and polypropylene with dispersed calcium chloride (2 and 4 wt %) were produced and biaxially stretched to induce the formation of cavities. The resulting cavities in these films account up to 10 vol % and are able to contain emerging calcium chloride solution formed by water vapor absorption. These films absorb reversibly up to 15 wt % water vapor at 75% relative humidity at 23 °C. This absorption behavior is described by effective diffusion and effective sorption coefficients. Using a simple model, the effective water vapor diffusion coefficient of these films can be estimated from the permeation coefficient of the polymer and the sorption coefficient of the absorber. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45713.