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RESEARCH PRODUCT

Effect of the extensional flow on the properties of oriented nanocomposite films for twist wrapping

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In this study, we examined the mechanical behavior of nanocomposite films based on polyethylene (PE) and pristine PE films. The films were prepared by film blowing and were then cold-drawn at low temperature. The experimental results show that cold drawing significantly enhanced the orientation; with increasing draw ratio (DR), the elastic modulus and tensile strength of the PE films strongly increased, particularly in the presence of the organoclay. To obtain polymeric films suitable for twist wrapping, the films must be sufficiently stiff so that no shrinkage or elastic recovery occur during or after twisting. The elongation at break and the yield strain sharply decreased with orientation, mainly in films upon drawing. According to the mechanical behavior, the twist angle increased with increasing DR and, particularly, with the addition of nanoclay, probably because of the applied DR, which reduced the nanoparticle size and, as a consequence, hindered the applied torsional elastic recovery. Therefore, the nanocomposite film with a higher DR was particularly suitable for twist-wrapping applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011