Infrared Spectroscopic Characterization of Polymer and Clay Platelet Orientation in Blown Films Based on Polypropylene‐Clay Nanocomposite

Abstract

The “tilted film” transmission infrared spectroscopy method was used to characterize the biaxial orientation in a set of blown films containing polypropylene (PP), layered silicate nano‐reinforcement, and two different compatibilizing agents based on maleic‐anhydride‐grafted PP. Both interactive spectral subtraction and peak fitting were used to determine trichroic ratios. The biaxial orientation of the polymer chains could be clearly quantified according to well‐established relationships for PP. In addition, the clay platelet orientation could be determined from the trichroism of the SiO stretching bands around 1100 – 1000 cm−1. The clay orientation was found to be quite high (Hermans orientation function around +0.8) and was not significantly affected by the presence of compatibilizing agent.

Investigation of water absorption in clay-reinforced polypropylene nanocomposites

“…These authors concluded that while the permeability decreased significantly, the amount of moisture absorbed remained mostly unchanged. Although they are outside the scope of this article, measurements of polymer and clay platelet orientation at the surface of the injected specimens by means of infrared spectroscopy in the attenuated total reflection mode have shown that the clay platelets are highly oriented parallel to the surface, in a manner similar to that observed for blown PP films [16]. This result suggests that, as discussed above, the barrier properties of our different nanocomposites during a subsequent exposure to water should be improved, by creating a maze-like tortuous path that should retard the progress of water molecules through the matrix resin.…”

Infrared spectroscopy as a tool to monitor the extent of intercalation and exfoliation in polymer clay nanocomposites

“…In addition, the stretching vibrations of the basal oxygen bonds with silicon are at around 1117, 1050 and 1020 cm À1 [6]. As noted by Cole et al [7] the clay Si-O stretching bands are indeed complex. For the fit of the stretching vibrations two components for each of the peaks at 1050 and 1070 cm À1 were used.…”

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.…”