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Effect of the thermal treatment of ionomer films on permeability and permselectivity
Author(s) -
AlAti Tareq,
Hotchkiss Joseph H.
Publication year - 2002
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.11262
Subject(s) - ionomer , crystallinity , permeability (electromagnetism) , materials science , differential scanning calorimetry , polyethylene , chemical engineering , ethylene , polymer chemistry , scanning electron microscope , composite material , chemistry , polymer , copolymer , membrane , organic chemistry , thermodynamics , engineering , biochemistry , physics , catalysis
Ionomers have been studied in detail and have gained widespread commercial use. Interested in altering the ratio of CO 2 /O 2 permeability (i.e., permselectivity) of films for use in packaging respiring produce, we pressed sodium‐neutralized poly(ethylene methacrylic acid) ionomers into films at 120–160°C and investigated their thermal, morphological, and permeability properties. The heat treatment of the ionomers at 160°C increased the gas permeability for O 2 more than for CO 2 and reduced the CO 2 /O 2 permselectivity ratio from 4.1 to 1.6. The reasons for these changes in the permeability characteristics of the ionomers are not understood but could be related to a reduction in the polyethylene (PE) crystallinity and the destruction of the aggregates into smaller, dispersed clusters. These results were supported by differential scanning calorimetry data and scanning electron micrographs. This suggests that the heat treatment of ethylene–methacyrlic ionomers may improve their potential for applications as selective barriers for modified‐atmosphere packaging of respiring produce. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2811–2815, 2002