Effects of graphene concentration, relative density and cellular morphology on the thermal conductivity of polycarbonate–graphene nanocomposite foams. (February 2016)

• Record Type: Journal Article
• Authors: Gedler, G.; Antunes, M.; Borca-Tasciuc, T.; Velasco, J.I.; Ozisik, R.
• Is Part Of: European polymer journal. Volume 75(2016:Feb.)
• Page Start: 190
• Page End: 199
• Publication Date: 2016-02
• Subjects: Thermal conductivity -- Polycarbonate -- Graphene -- Nanocomposite foams; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2015.12.018
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: Polycarbonate–graphene foams were prepared via 1- and 2-step scCO2 foaming. Thermal conductivity of foams increased linearly with augmenting relative density. Foams prepared via 1-step displayed higher thermal conductivities than 2-step foams. The addition of higher GnP amounts led to foams with higher thermal conductivities. GnP's effect in enhancing conductivity was less marked with increasing its content. Abstract: The thermal conductivity of polycarbonate–graphene nanocomposite foams was studied as a function of relative density, developed cellular structure and graphene concentration. Two types of supercritical CO2 foaming processes were employed to obtain foams with a wide range of relative densities and cellular morphologies. The thermal conductivity of unfoamed nanocomposites increased in more than two times upon addition of 5 wt% graphene. Foaming led to lowered thermal conductivity values, as low as 0.03 W/(m K), with thermal conductivity being mainly controlled by relative density and in a lower extent by graphene concentration. Higher thermal conductivities were obtained with increasing relative density and cell size, as well as with increasing graphene concentration, especially in those cases where improved graphene dispersion was achieved with foaming. Thermal conductivity values displayed a better fit when using a three-phase model when compared to the two-phase model previously proposed for polymer composite foams.