Morphology and gas barrier properties of polyethylene‐based nanocomposites

Abstract

Nanocomposites were processed by melt blending two reference matrices, a metallocene polyethylene and a low density maleic anhydride-grafted polyethylene with an organo-modified montmorillonite. It was shown that the introduction of a maleated polyethylene compatibilizer was required to improve the clay nanoplatelet dispersion in the metallocene polyethylene-based nanocomposites. Increasing the montmorillonite content led to a significant increase of the barrier properties. Interfacial agents such as oxidized paraffins were shown to be more effective to reduce the gas permeability than maleated polyethylene and the dependence of the gas transport properties was discussed not only as a function of the clay dispersion but also as a function of the clay/compatibilizer and compatibilizer/matrix interactions. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 431-440, 2006

Tailored Polyethylene Nanocomposite Sealants: Broad-Range Peelable Heat-Seals Through Designed Filler/Polymer Interfaces

“…This performance was achieved through a synergy of montmorillonite nanofillers and EVA-copolymer additive, that resulted in a general cohesive failure behavior. This resulted in peelable heat seals independent of sealing method (ranging from high pressure and 8 s dwell time, to low pressures and sub-second dwell times) over a very broad range of seal temperatures (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) • C range for the nanocomposites, instead of 2-5 • C for neat PE sealants, or 10 • C for PB-containing peelable sealants), as well as markedly independent of the seal substrate (on itself, on typical PE sealants and on HDPE). The origins and the mechanism of Figure 12.…”

“…Given the extensive use of polyethylene sealants worldwide, and the possible enhanced performance of polyethylene/clay nanocomposite films (which combine high gas barrier, optical transparency and improved thermomechanical properties [29][30][31][32][33][34][35]) it is very timely to study and tailor the heat-sealing performance of PE/clay nanocomposites, if their use in flexible packaging is to be proliferated. In general, fused PE seals are well established and are straightforward to realize and to manufacture.…”

Reinforcement of the Gas Barrier Properties of Polyethylene and Polyamide Through the Nanocomposite Approach: Key Factors and Limitations

“…Maleic anhydride grafted polyolefins are the most common interfacial agents used in polyolefin based nanocomposites. The interest of oxidized paraffins for gas barrier properties was first demonstrated by our team few years ago [29,30] and then confirmed by other groups [31]. For this study, nanocomposites with the following weight composition 75 wt% PE/20 wt% interfacial agent/5 wt% MMT-Tallow were prepared by melt blending according to the protocol described in the experimental part.…”

“…Hence much attention has been paid to obtain such morphologies, characterized by a high degree of clay exfoliation. However, the simple tortuous path model which considers the nanocomposite as an ideal binary system can not explain some experimental observations in the literature that yield either much lower [43][44][45] or on the contrary much higher permeability values than predicted [22,[28][29][30]. New conceptual approaches consisting in considering heterogeneous materials as resulting from three phases, namely the continuous phase, the dispersed phase and the interface, have progressively come to light [22,28,30,[43][44][45][46][47].…”

“…A lot of attention has been particularly paid these last years on nanofillers such as clays to reinforce PA or PE properties [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Indeed due to their high aspect ratio and their impermeable character, the clay platelets are expected to induce significant tortuosity effects when they are dispersed within a polymer matrix.…”