Polyester nanocomposites

The effect of loading (0.5,1.0 and 2.0 wt%) nanostructured polyaniline (PANI) on the physiochemical, physicomechanical, morphological and thermal properties of soybean oil-based polyester nanocomposites has also been reported. The nanocomposites of conjugated linseed oil, acrylic acid and divinylbenzene are synthesised using modified montmoriUonite clay. The resultant nanocomposites exhibit a storage modulus in the range of 17-79 MPa at the glass transition temperature compared to the pristine polymer which is 2.1 MPa. The nanocomposites show better thermal stability (up to 200°C) than the pristine polymer. 

Jin and Park processed the Al O -epoxy nanocomposites by hot curing technique [69]. Zheng et al. prepared the SiO -epoxy nanocomposites by mixing the nanoparticles in epoxy matrix at 120°C [4]. Similarly, SiO -based thermoset polyester nanocomposites are prepared by mechanical mixing followed by ultrasonication [72]. Alumina-epoxy nanocomposites are also processed in-situ by reducing the size of alumina particles from micrometer range to nanometer range with the assistance of mechanical vibrator [73]. 

Furthermore, modeling of the esterification reaction was attempted in the presence of silica nanoparticles during the formation of aliphatic polyester nanocomposites. From the experimental data, it was found that on increasing the Si02 content in esterification, the rate of water production decreases [47]. In addition, it was clear that the total quantity of water released does not depend on the nanoparticle concentration. This suggests that the existence of the particles does not influence the esterification reaction itself. Their main effect is to adsorb the produced water before it evaporates, altering in this way the water evaporation curve. The simplest model for this phenomenon is to assume very fast water adsorption/desorption kinetics on the Si02 particles. In this case, the evaporation kinetics must be explicitly taken into account because it is no more very fast compared to the other phenomena that occur. 

Figure 9.1 TEM micrographs of crosslinked polyester nanocomposite containing 2.5 wt% clay showing (a) microstructure at low magnification, (b) intercalated and exfoliated...

Figure 13.34 A plot of oxygen permeability of 10-mil thick amorphous compression molded films vs. clay loading, tor a series of polyester nanocomposites. PETG is glycol-modified poly(ethylene terephthalate), PET is poly(ethylene terephthalate), and PEN is poly(ethylene naphthalate). The effective aspect ratio of these composites is in the range of 150-200.

Thermotropic LC polyester nanocomposites based on a small quantity of multi-walled carbon nanotubes (M WCNTs) can be prepared by in situ polymerization of l,4-bis(4-hydroxybenzoyloxy) butane and terephthaloyl dichloride. Significant change in the crystal structure of LC polyester cannot be observed even after forming the nanocomposite. The evidence from various instrumentation results indicates interaction of MWCNT with the surrounding liquid crystal molecules, most likely through aromatic interactions (H-stacking), The thermal stability and transition temperature of the hybrid is always better than pure LC polyester [71]. 

Simsek Y, Ozyuzer L, Seyhan AT, Tanoglu M, Schulte K (2007) Temperature dependence of electrical conductivity in double-wall and multi-wall carbon nanotube/polyester nanocomposites. J Mater Sci 42(23) 9689-9695... 

Fig. 17 X-ray scattering profiles for organically modified montmorillonite clay (Closite 30B) and crosslinked polyester nanocomposites containing 1, 2, 5, and 10wt% clay. Reprinted from (2002) Polymer 43 3699 [158] with permission...

Multiwall Carbon Nanotube Reinforced Polyester Nanocomposites... 

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