Premium
Mathematical analysis of transport properties of polymer films for food packaging. VI. Coupling of moisture and oxygen transport using langmuir sorption isotherms
Author(s) -
Howsmon Gregg J.,
Peppas Nikolaos A.
Publication year - 1986
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.1986.070310711
Subject(s) - adsorption , langmuir , sorption , partial pressure , moisture , oxygen , polymer , food packaging , chemical engineering , permeation , materials science , chemistry , membrane , composite material , organic chemistry , food science , biochemistry , engineering
Deterioration of food products stored in flexible packaging materials can be attributed to the presence of both water and oxygen in the environment surrounding the food. Mathematical models for the simultaneous permeation of moisture and oxygen through the packaging polymeric film and subsequent adsorption on the food surface are presented for the case of competitive adsorption of the two diffusing species. These models are then used to predict internal packaging conditions over time for selected food products. Oxygen and moisture permeation are treated as independent phenomena, and the competition is regarded as occuring on a surface described by the Langmuir adsorption isotherm. It is found that for certain polymer physical properties and relative surface coverages, water and oxygen molecules can dislodge each other from the food surface and, even for situations where the initial partial pressure of oxygen is less than the external partial pressure, can cause an outward flow of the more weakly adsorbed material. This theory is then extended to incorporate varying external conditions of storage.