Thermal diffusivity of in-situ exfoliated graphite intercalated compound/polyamide and graphite/polyamide composites

Abstract

Abstract. The thermal diffusivity of graphite intercalated compound (GIC)/polyamides (PA6, PA66 and PA12) and graphite/polyamides composites were investigated. The polyamides/GIC composites were prepared by an in-situ exfoliation melting process and thermal diffusivity of the composites was measured by a laser flash method. The surface chemistry of the GIC and graphite was investigated using Fourier transform infrared spectroscopy, the fracture morphology of the composites was observed by field emission scanning electron microscopy. The thermal diffusivity of the in-situ exfoliation processed PA/GIC composites showed a significant improvement over those of PA/expanded graphite intercalated compound composites and PA/graphite composites. We suggest that the larger flake size and high expansion ratio of the GIC during the in-situ exfoliation process leads to 3-dimensional conductive pathways and high thermal diffusivity. Thermal diffusivity of the polyamides/GIC (20 vol%) composites was increased approximately 18 times compared to that of pure polyamides.

Thermal, electrical and rheological behavior of high-density polyethylene/graphite composites

“…Therefore, EG is widely used as flame-retardant additives in polyurethane foams [27] and polymer-based composites [28] due to its intumescent nature. However, the exfoliation of EG also makes it easier to form three-dimensional (3D) conductive pathways [29,30] within the polymer blends that facilitates the construction of conductive networks within the EG-containing composites, which is crucial to the overall thermal/electrical conductivity of the resultant composites. Moreover, the expanded graphite exhibits a layered structure similar to layered silicates and has a good affinity with polymers [31].…”

Effect of surfactant and electron treatment on the electrical and thermal conductivity as well as thermal and mechanical properties of ethylene vinyl acetate/expanded graphite composites

“…[14][15][16] Ethylene copolymers like EVA belong to polymers which can be cross-linked by high-energy electrons without any use of additional cross-linking agents. High-energy electron induced cross-linking is mainly performed at ambient temperature and leads to the formation of three-dimensional networks.…”

Reactive microencapsulation of carbon allotropes in polyamide shell-core structures and their transformation in hybrid composites with tailored electrical properties

“…CB powders are much cheaper than CNT which is important for industrial applications, however their percolation thresholds are significantly higher -0.7-2.1 wt% for CNT against 4.3 wt% for CB introduced into PA12 matrix [24]. Exfoliated GR-containing polyamides have been prepared and investigated predominantly in terms of increasing the mechanical properties [25] or thermal diffusivity [26] of the matrix material, whereby the larger the GR stacks size and their exfoliation ratio, the more effective the formation of 3-dimensional conductive pathways and high thermal diffusivity. A clear trend toward GR filler chemical modification is observed mainly by oxidation and polymer grafting in order to increase the miscibility with the polyamide matrix [27,28].…”