Graphene fillers are generally prepared by oxidizing graphite flakes in strong acids to generate graphene oxide (GO). GO sheets are heavily oxygenated, bearing hydroxyl and epoxide functional groups on their basal planes, in addition to carbonyl and carboxyl groups at the sheet edges [13]. As a result,

GO sheets can P5091 order mix intimately with many organic polymers, facilitating the synthesis of GO/polymer composites with homogeneous dispersion of nanofillers. However, GO is an electrically nonconductive material; thus, the oxygenated functional groups must be removed either by reacting with chemical agents to form chemically reduced graphene or heating in a furnace to yield thermally reduced graphene (TRG) [10, 11, 14, 15]. In a previous study, we reported the preparation of electrically conductive

TRG/polymer composite by mixing GO in a polymer solution followed by hot pressing [16]. The in situ TRG sheets were dispersed homogenously in the polymer matrix. The SB-715992 price main disadvantage of this approach, however, is that the percolated composites have a relatively low SAR302503 datasheet electrical conductivity, resulting from incomplete thermal reduction of GO. The low conductivity can greatly limit potential applications of the composites. In the past decade, the synthesis of one-dimensional metal nanomaterials has received great attention from chemists, materials scientists, and physicists. These materials include Ag [17, 18], Cu [19, 20], Au [21, 22], and CuNi [23] nanowires (NWs). The incorporation of those nanowires with unique properties into polymers can yield novel composites with functional characteristics. For example, da Silva et al. incorporated CuNWs into polyvinylidene fluoride (PVDF) and found that the

CuNW/PVDF nanocomposites exhibit high dielectric permittivity and low dielectric loss [24]. Conductive polymer composites generally show Monoiodotyrosine a large increase in electrical resistivity by heating near the glass transition or melting temperature of the polymer matrix. This behavior is widely known as the ‘positive temperature coefficient’ (PTC) effect. The mechanisms responsible for the PTC effect are rather complex. PTC effect may arise from a difference in thermal expansion coefficient between the polymer matrix and conductive fillers. In addition, other factors such as the type, size and dispersion state of fillers, and the type of polymers can affect the PTC behavior [25–38]. From the literature, many researchers have extensively studied the PTC behavior of polymer composites filled with carbon blacks (CBs) in the past two decades [26–32]. Kim et al. incorporated 40 to 60 wt % CBs (0.86 and 0.3 μm) into PVDF, polyacetal, polyester, polyamide-11, and polyamide-12 [29]. They reported that the PTC intensity of polymer composites was proportional to the polymer crystallinity.