Analysis of the structure and mass transport properties of clay nanocomposites based on amorphous PET

Abstract

The aim of this work is to characterize the rheological and permeability behavior of nanocomposites based on amorphous poly(ethylene terephthalate) (PETg) and organically modified montmorillonites (omMMT), obtained by melt intercalation. The use of PETg instead of semicrystalline PET is believed to reduce the risks associated to organic modifier degradation during processing at high temperatures. X-ray and transmission electron microscopy analysis performed on the PETg nanocomposites showed that processing for long time at temperatures lower than melting of semicrystalline PET allowed to obtain a partially intercalated structure with some degree of exfoliation. The rheological behavior of PETg nanocomposites was studied as a function of shear rate in a coneplate rheometer in order to correlate the viscosity with the aggregation state of omMMT. A simple model accounting for an apparent increase of rheological units size, associated with the intercalation of PETg macromolecules into omMMT galleries, is proposed. The glass transition temperature, T g , as a function of the volume fraction of omMMT content of the nanocomposite, was measured using differential scanning calorimetry. Finally, the water vapour permeability of PETg nanocomposites was correlated to the volume fraction of the impermeable inorganic part of the omMMT.

Two-dimensional and three-dimensional simulation of diffusion in nanocomposite with arbitrarily oriented lamellae

“…One of the most promising applications of polymer nanocomposites based on high aspect ratio inorganic platelets is given by the possibility of significantly improving the barrier properties towards gases and vapors using a low amount of nanofiller [1][2][3][4][5]. The increase of the barrier properties of polymer nanocomposites is usually attributed to the increase in the tortuosity of the path that a diffusing molecule must travel across a nanocomposite film [6].…”

Preparation and Characterization of EG-Chitosan Nanocomposites via Direct Exfoliation: A Green Methodology

“…The most studied polymer nanocomposites are composed of thermoplastic or thermosetting matrix, clay [1][2][3][4][5][6][7], or carbon nanotubes (CNTs) and graphene nanoplatelets [8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

Development and characterization of novel photopolymerizable formulations for stereolithography

“…The final material displays either an intercalated or an exfoliated morphology, depending on the level of interactions achieved in between the two phases [7]. The most widely studied nanocomposites, whether based on thermoplastic or thermosetting matrices, are generally produced from organically modified montmorillonites (OM) [8][9][10][11][12][13][14][15]. Only a few examples related to the use of boehmite (c-Al 2 O 3 ) to prepare nanocomposite materials have been reported in the literature [16][17][18].…”