Surfactant concentration effects on amorphous PETG–montmorillonite layered silicate (MLS) nanocomposite films

Abstract

Improvements in the dispersion of montmorillonite layered silicates (MLS) have centered on appropriate surfactant treatment of the MLS, to ensure chemical interaction with the polymer material. Here, polyethylene terephthalate glycol (PETG) nanocomposites made with two MLS cation exchanged with dimethyl dihydrogenated tallow quaternary ammonium at two concentrations, 95 (MLS‐95) and 125 meq (100 g)−1 (MLS‐125), were investigated. The host MLS had a cation exchange capacity (CEC) around 92 meq (100 g)−1. The effect of exchanging past the CEC was studied with respect to the dispersion, glass transition and mechanical properties. Films were extruded on a single‐screw extruder with a film die attached. X‐ray diffraction (XRD) and optical transmission measurements indicated that increasing surfactant concentration changed the dispersion from intercalated to immiscible. The differences in the dispersion were related to the inherent degradation temperature of the MLS treated with the different surfactant concentrations, relative to the processing temperature. The over‐exchanged MLS (MLS‐125) suffered more surfactant degradation leading to an immiscible dispersion and narrower XRD peaks reflected a higher degree of ordering. In contrast, the XRD peaks of the MLS‐95 nanocomposites had increased breadth indicating decreased ordering. MLS orientation, however, did not influence birefringence measured by polarized Fourier‐transform infrared spectroscopy (FTIR). All nanocomposites showed no significant changes in the glass transition temperatures. Copyright © 2005 Society of Chemical Industry

Effect of clay surfactant type and clay content on the rheology and morphology of uncured fluoroelastomer/clay nanocomposites prepared by melt‐mixing

“…A similar XRD behavior was reported for nanocomposites of polyethylene terephthalate glycol (PETG), using the 15A and 20A nanoclays 28. It was shown that PETG/15A compounds had substantially better reinforcement than PETG/20A compounds 28.…”

“…26,27 A similar XRD behavior was reported for nanocomposites of polyethylene terephthalate glycol (PETG), using the 15A and 20A nanoclays. 28 It was shown that PETG/15A compounds had substantially better reinforcement than PETG/20A compounds. 28 The XRD peaks of 20A compounds shifted to lower angles and 15A showed no change, which was similar to our observations in Figure 4.…”

“…28 It was shown that PETG/15A compounds had substantially better reinforcement than PETG/20A compounds. 28 The XRD peaks of 20A compounds shifted to lower angles and 15A showed no change, which was similar to our observations in Figure 4. The justification provided was that the 15A compounds were highly oriented compared with 20A, resulting in more platelet-platelet interaction thereby strengthening the composite.…”

Structure and Mechanical Properties of Nanocomposites Based on an Amorphous Copolyester

“…These increases are due exclusively to the OMMT presence, because the orientation, as measured by means of birefringence, was the same in the pure PCTG and in the PNs. A case where the OMMT does not contribute to birefringence, as measured by FTIR, has also been observed in PETG-based [36] PNs. A linear increase in properties such as the modulus is often seen in PNs, [4,55] although at high OMMT content the slope decreases.…”

“…[33] A methyl tallow bis(2-hydroxyethyl) ammonium organic modification led to better dispersion than octadecylamine or dodecylamine modifications. [34] In the case of 1,4-cyclohexanedimethanol-terephthalic acid-ethylene glycol copolymer (PETG), the effects of the organoclay presence on the viscoelastic properties [35] and on the properties of its films [36,37] were studied. However, to our knowledge, no work has been published based on PCTG, which is a copolymer with the same components as those of PETG, but with different proportions of the chemical groups.…”