Effect of functionalized graphene on the physical properties of linear low density polyethylene nanocomposites

Dodecyl amine-modified graphene (DA-G)/linear low density polyethylene (LLDPE) nanocomposites were prepared through solution mixing. Field emission scanning electron microscopy analysis revealed homogeneous dispersions of graphene layers in the nanocomposites. X-ray diffraction analysis showed that the average crystallite size of the nanocomposites was increased. However, the % crystallinity was found to decrease due to the formation of a random interface. Dynamic mechanical analysis showed that the storage moduli of the nanocomposites were much higher than that of neat LLDPE. The nanocomposites were also more thermally stable than neat LLDPE. Isothermal thermogravimetry showed that homogeneously distributed graphene could act as a good inhibitor during thermal degradation of the nanocomposites. Differential scanning calorimetry showed that the crystallization temperature of the nanocomposites increased with increasing DA-G content. Thermomechanical analysis showed that the dimensional stability of the nanocomposites was significantly increased by the addition of the DA-G. The coefficients of thermal expansion decreased with increasing DA-G content. The oxygen and nitrogen permeability of the nanocomposites was lower than that of neat LLDPE. (C) 2011 Elsevier Ltd. All rights reserved.