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The relative significance of biaxial stretch ratio effects on the permeability of oriented PET film
Author(s) -
Fan G.,
Di Maio L.,
Incarnato L.,
Scarfato P.,
Acierno D.
Publication year - 2000
Publication title -
packaging technology and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 50
eISSN - 1099-1522
pISSN - 0894-3214
DOI - 10.1002/1099-1522(200005)13:3<123::aid-pts502>3.0.co;2-g
Subject(s) - materials science , permeability (electromagnetism) , composite material , relative permeability , structural engineering , engineering , chemistry , porosity , biochemistry , membrane
In this paper the relative influence of the stretch ratio in machine direction (MD) and transverse direction (TD) on the permeability of tubular polyethylene terephthalate (PET) films was studied. The biorientation process was realized on a laboratory scale by means of a double‐bubble tubular film apparatus. In order to evaluate interaction between the stretch ratios in MD and TD on barrier properties, an experimental design to measure the interaction of two independent variables was applied. The study was also performed on annealed PET films. The results have shown that some degree of interaction exists between the stretch ratio in MD and TD. In particular, for annealed PET films, the relative influence of the stretch ratio in MD and TD depends largely on the size of the penetrant gas: the lowest permeability results were obtained using the highest second draw ratio (SDR) values for CO 2 and the lowest second blow‐up ratio (SBUR) values for N 2 , respectively. However, it was verified that annealing strongly influences the barrier properties of PET films. Copyright © 2000 John Wiley & Sons, Ltd.