Segmental dynamics of functional graphene-filled poly(ether sulfone ether ketone ketone) nanocomposites

The segmental dynamics of functional graphene (fGR)/poly(ether sulfone ether ketone ketone) (PESEKK) nanocomposites were investigated via differential scanning calorimetry and dynamic mechanical analysis (DMA) measurements. First, fGR was prepared using graphene oxide and sodium dodecylbenzene sulfonate. Subsequently, a series of fGR/PESEKK nanocomposites were prepared through solution blend. When the sulfone groups were introduced into the segments of PESEKK polymers, the glass transition temperature (T-g) of PESEKK was higher than that of free sulfone functionalized poly(ether ketone ketone). The fGR/PESEKK nanocomposites displayed a uniform nanostructure because of the strong interfacial interaction between fGR and PESEKK. With the increase in the fGR contents, the T-g values of fGR/PESEKK nanocomposites decreased. Two loss factor peaks were noted in the fGR/PESEKK nanocomposites, which were characterized via DMA. The alpha'-relaxation of the nanocomposites at low temperature was assigned to polymer chains close to the polymer/filler interface with mobility higher than that in the bulk unfilled PESEKK (alpha-relaxation). (C) 2016 Wiley Periodicals, Inc.