Fabrication of microcellular polymer/graphene nanocomposite foams

Abstract

Graphene has recently gained revolutionary aspirations because of its remarkable electronic, thermal and mechanical properties. These unique properties make it promising for preparing multifunctional nanocomposites. In recent years, polymer foams based on graphene have also received increasing attention in both the scientific and industrial communities. This review presents an overview of polymer/graphene nanocomposite foams discussing the production of graphene, the polymer functionalization of graphene and different polymer/graphene foams with different properties. One of the most promising avenues is to fabricate tough and lightweight materials with superior electrical and electromagnetic interference shielding properties. Copyright © 2012 Society of Chemical Industry

Effects of graphene nanoplatelets on the morphology of polycarbonate–graphene composite foams prepared by supercritical carbon dioxide two-step foaming

“…Thus, foaming processing conditions play an essential role in the final morphological/microstructural characteristics of the resulting foams. On the other hand, several studies have indicated that a small amount of well-dispersed nanoparticles can act as cell nucleation sites and that nucleation efficiency is dependent on particle size, shape, surface properties and dispersion quality [2,4,9]. In addition, it has been shown that the combination of graphene nanoplatelets and scCO 2 during foaming may have remarkable effects on the microstructure of the developed foams [10].…”

“…Two scCO 2 dissolution temperatures were considered: 80 and 100 ºC, in both cases applying a dissolution time of 210 min. The scCO 2 was initially introduced in the vessel at 70 bar, reaching a final dissolution pressure of 140 and 180 bar, respectively for 80 and 100 ºC. Once carbon dioxide was dissolved into the foam precursors, these were cooled down to room temperature by re-circulating water through the vessel's cooling jacket while keeping the vessel pressurized at 15 ºC/h in order to avoid undesirable pre-foaming.…”

“…The use of supercritical carbon dioxide (scCO 2 ) dissolved into a given polymer has become one of the most common strategies used to prepare graphene-filled polymer foams [2][3][4]6]. Carbon dioxide acts as polymer plasticizer, decreasing its glass transition temperature and facilitating expansion due to decreased polymer viscosity [7], in some cases even leading to cell coalescence and as a result to a decrease in cell density [8].…”

“…In the case of one-step foaming, CO 2 dissolution, expansion and cooling of samples takes place inside the high pressure vessel, while in two-step foaming the expansion stage can be done either inside the same vessel used to initially dissolve the carbon dioxide or outside by heating the CO 2 -saturated samples using an oil bath [16] or a hot-press [15]. Particularly, graphene-filled polycarbonate foams have been prepared by both one-step [6] as well as two-step foaming [17].…”

“…Graphene-filled polymer foams have recently aroused a great interest in the scientific and industry communities [1][2][3][4], as the incorporation of graphene can dramatically enhance the electrical, physical, mechanical and barrier properties of polymers at extremely low loadings and, as a consequence, extend their potential applications to fields such as electronics, aerospace, automotive, green energy, among others [5]. The use of supercritical carbon dioxide (scCO 2 ) dissolved into a given polymer has become one of the most common strategies used to prepare graphene-filled polymer foams [2][3][4]6].…”