Low density polyethylene–montmorillonite nanocomposites for film blowing

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

“…The general trends (in both the machine and the transverse directions of the blown film) included: a substantial increase in tensile Young's modulus (80 to 160% increase for 2 to 5 wt% mmt), no marked change in the tensile strength (a slight 10% improvement in machine direction and a 10% decrease in the transverse direction), no marked change in the yield stress and strain, and a small decrease in the tensile strain at break (from 550% to 460% in the machine direction, whereas in the transverse direction remained unchanged at 650 ± 50%). These trends strongly reflect the proper choice of the functionalized PE in the montmorillonite masterbatch, namely a functional MAH-graft-LLDPE with a molecular weight and density commensurate with the LDPE/LLDPE sealant blend, rather than a straightforward effect of the clay dispersion [29]. …”

“…However, in contrast with polar and/or thermosetting polymers, non-polar polymers -such as polyolefins -still present a challenge in preparing well-defined melt-processable nanocomposites with layeredsilicates [27,28]; they typically require a two-step processing via dilution of a masterbatch, i.e., a concentrate of a layered-silicate or clay predispersed in a functionalized form of the same polyolefin. For example, direct melt blending of polyethylene (PE) with organically modified clays (organoclays) typically results in microcomposites [27][28][29], whereas functionalized-PE/layered-silicate masterbatches can facilitate reproducible PE nanocomposite structures [29], even at a large (industrial) scale. In such masterbatch approaches, organoclay is first dispersed at high concentration in a functionalized matrix, for example, maleic anhydride containing polyethylene, and is subsequently diluted/melt-processed with the desired neat polymer, in this example unmodified polyethylene, to obtain the desired nanoscale dispersion.…”

“…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.…”

Thermoplastic Nanocomposites and Their Processing Techniques

“…The processing of polymeric materials (such as plastics, elastomers and composites, etc) is characterized by a wide variety of distinct techniques such as extrusion (Vaia et al, 1994), film blowing (Golebiewski et al, 2008), sheet thermoforming (Feng et al, 2009), blow molding (http://www.petmachine.in/type_of_blow_moulding.htm), and injection molding (Chandra et al, 2007), etc. Extrusion is the continuously shaping of a fluid polymer and/or its nanocomposite through the orifice of a suitable tool (die) (Figure 6a), followed by solidifying it into extrudate of constant cross section.…”

Synthesis and Thermal and Textural Characterization of Aniline Formaldehyde-Organoclay Composites

“…In recent years, polymer based nanocomposites reinforced with Na-Montmorillonite nanoclay particles have drawn significant attention. This is due to the fact that these types of composites show substantial improvements in mechanical, thermal and barrier properties over the pure polymer, and therefore, have * corresponding author; e-mail: ahmetgu@yahoo.com potential in high-performance applications [5][6][7][8][9][10][11][12]. It is well known that nanoparticles can also enhance the mechanical properties and thermal degradation of nanocomposites.…”