Enhanced Thermal Conductivity of Phase Change Materials Modified by Exfoliated Graphite Nanoplatelets

2009 ◽  
Vol 1218 ◽  
Author(s):  
Jinglei Xiang ◽  
Lawrence Drzal
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Particle Orientation ◽  
Exfoliated Graphite ◽  
Critical Parameters ◽  
Gravimetric Analysis ◽  
Graphite Nanoplatelets ◽  
Scanning Calorimetry ◽  
Exfoliated Graphite Nanoplatelets

AbstractComposite phase change materials (PCM) were prepared by mixing exfoliated graphite nanoplatelets (xGnP) into paraffin wax. The two types of graphite nanoplatelets that were investigated were xGnP-1 having thickness of 10 nm and a diameter of 1 um and xGnP-15 having the same thickness with a platelet diameter of 15 um. Direct casting and two roll milling were used to prepare samples. Scanning electron microscopy images show that the nanofillers disperse very well in paraffin matrix without noticeable agglomeration. Paraffin/xGnP-15 PCM consistently exhibited higher thermal conductivity than xGnP-1 PCM. The improvement in thermal conductivity was as high as 5 fold for xGnP-15 composites and 2 fold for xGnP-1 composites at 4 vol%. The aspect ratio, particle orientation, and interface density between the conductive particles and the polymer matrix were found to be the critical parameters in determining the conductivities of the resulting nanocomposites. The thermal physical properties of the nanocomposites were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). It was found that the latent heat of nanocomposites was not negatively affected in the presence of xGnP particles and the thermal stability improved.

Preparation and Characterization of Tetradecanol Microcapsule Phase Change Materials by Emulsion Polymerization

2015 ◽  
Vol 1089 ◽  
pp. 137-141 ◽  
Author(s):  
Xiao Qiu Song ◽  
Long Di Cao ◽  
Dan Dan Xu
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Result Show ◽  
Ft Ir ◽  
Latent Heats ◽  
Test Result

In this study, it was aimed at preparing and characterizating of poly (methyl methacrylate) (PMMA) shell microcapsules containing tetradecanol as phase change materials (PCMs) for thermal energy storage. The tetradecanol microcapsules were characterized by using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The test result show that the contents of tetradecanol in microcapsules nearly 57.5% and the latent heats of melting and freezing were found to be 120.7 and 118.4 J/g. TGA analyses also indicated that the microPCMs degraded in two steps and have good thermal stability.

scholarly journals Thermal Conductivity of a Monolayer of Exfoliated Graphite Nanoplatelets Prepared by Liquid-Liquid Interfacial Self-Assembly

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Jinglei Xiang ◽  
Lawrence T. Drzal
Keyword(s):  
Thermal Conductivity ◽  
Self Assembly ◽  
Average Particle Size ◽  
Peak Shift ◽  
Exfoliated Graphite ◽  
Average Particle ◽  
Graphite Nanoplatelets ◽  
Cross Sectional ◽  
Packed Structure ◽  
Exfoliated Graphite Nanoplatelets

A monolayer film composed of exfoliated graphite nanoplatelets (xGnPs) was extracted from a chloroform-water interface and supported on a glass substrate. The nanoplatelets are interconnected at the edges without overlapping forming a very densely packed structure with uniform thickness. Micro-Raman spectroscopy with a 50 mW 532 nm laser generating heat at the center of a xGnP sample was used to probe the thermal conductivity of the xGnP monolayer at different power levels. The Raman G peak shift of graphite was used to record the local temperature rise in the monolayer. The cross-sectional area of heat conduction is determined by the thickness of individual nanoplatelets. A UV-Vis spectrometer was used to measure the absorption of light by the monolayer. Depending on the interface density, the thermal conductivities are around 380 W/m K and 290 W/m K for monolayers with average particle size of 10 μm and 5 μm, respectively.

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