Effect of Clay on Mechanical and Gas Barrier Properties of Blown Film LDPE/Clay Nanocomposites

Department of Chemical Engineering, Chulalongkorn University, Krung Thep, Bangkok, Thailand
Journal of Applied Polymer Science (Impact Factor: 1.77). 11/2007; 106(4):2210 - 2217. DOI: 10.1002/app.26839


Low density polyethylene (LDPE)/clay nanocomposites, which can be used in packaging industries, were prepared by melt-mix organoclay with polymer matrix (LDPE) and compatibilizer, polyethylene grafted maleic anhydride (PEMA). The pristine clay was first modified with alkylammonium salt surfactant, before melt-mixed in twin screw extruder attached to blown-film set. D-spacing of clay and thermal behavior of nanocomposites were characterized by Wide-Angle X-ray Diffraction (WAXD) and differential scanning calorimetry (DSC), respectively. WAXD pattern confirmed the increase in PEMA contents exhibited better dispersion of clay in nanocomposites. Moreover, DSC was reported the increased PEMA contents caused the decrease in degree of crystallinity. Mechanical properties of blown film specimens were tested in two directions of tensile tests: in transverse tests (TD tests) and in machine direction tests (MD tests). Tensile modulus and tensile strength at yield were improved when clay contents increased because of the reinforcing behavior of clay on both TD and MD tests. Tensile modulus of 7 wt % of clay in nanocomposite was 100% increasing from neat LDPE in TD tests and 17% increasing in MD tests. However, elongation at yield decreased when increased in clay loading. Oxygen permeability tests of LDPE/clay nanocomposites also decreased by 24% as the clay content increased to 7 wt %. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

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Available from: Anongnat Somwangthanaroj, Oct 05, 2015
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    • "To achieve the expected improvements in properties, preparation of nanocomposites requires extensive delamination of layered clay structure and uniform dispersion of the resulting platelets throughout the polymer matrix [9] [10]. In previous studies it has been demonstrated that the best performances are commonly observed for exfoliated nanocomposites [11] [12] [13] [14]. "
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    • "The wide commercial interest of LDPE blown films has triggered the study of blown films from LDPE-based NCs [20,24–31]. Their morphology, orientation and properties [26]; the effects of compatibilizers on dispersion [20] [24], mechanical properties [26], packaging-related barriers [27] [29], tear [20] [26] [28] [32] and creep properties [33] [34] [35] have all been studied. One study involving blown films based on a zinc ionomer NC [32] showed great improvements in properties with respect to those based on LDPE, due to the relatively easy exfoliation of the clay in the pure ionomer. "
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