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Keywords:

  • elastomers;
  • polyolefins;
  • membranes;
  • blends;
  • structure-property relations

ABSTRACT

Stretched thin films composed of a thermoplastic elastomer, a polystyrene-block-poly(ethylene butylene)-block-polystyrene triblock copolymer (SEBS), and polyolefins, poly(ethylene-co-ethylacrylate) and poly(ethylene-co-propylene), were obtained by blow-molding, uniaxial stretching, and cooling to room temperature and the gas permeability of the stretched films was investigated. When the as-blown annealed film was subjected to uniaxial stretching in the machine direction, PO2 and PN2 increased with an increase in the stretching ratio K and approached a constant value at high stretching ratios. In addition, PO2/PN2 decreased gradually with K and approached a value of 2.95–3.0. The reason for this unique gas permeation behavior is that the molecular mobility of poly(ethylene butylene) chains in a direction normal to the film increases and reaches an equilibrium state at around K = 4.5. The change in gas permeability of the stretched films can be explained using a deformation model for the SEBS matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39386.