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Graphene-Elastomer Composite for Energy Storage Applications
Published in Titash Mondal, Anil K. Bhowmick, Graphene-Rubber Nanocomposites, 2023
A. M. Shanmugharaj, Anil K. Bhowmick
In contrast to the liquid-phase exfoliation technique, thermal shock treatment involving rapid microwave heating of acid-treated graphite is the effective technique in producing bulk quantities of 10-nm-thick graphite nanoplatelets (Xiang and Drzal, 2011). The transmission electron microscopic (TEM) results of thermally exfoliated graphite nanoplatelets with large aspect ratio are shown in Figure 16.4 (Xiang and Drzal, 2011).
Cement-Based Composites with PCMs and Nanoinclusions for Thermal Storage
Published in Antonella D’Alessandro, Annibale Luigi Materazzi, Filippo Ubertini, Nanotechnology in Cement-Based Construction, 2020
Kaviarasu et al. [28] reviewed the use of nanoparticles in PCMs for building applications. They reported the use of exfoliated graphite nanoplatelets (xGnP), which is a porous nanosized carbon material useful as a supporting structure. In particular, the addition of 5 wt% xGnP in octadecane led to an increase of thermal conductivity by 101%. Organic fatty acid ester PCMs like coconut oil and palm oil (with Tm = 26.78°C and 17.26°C, respectively) were also incorporated into the porous structure of xGnP using the vacuum impregnation method [61].
Effect of Cu surface and graphene on the conformation of n-octadecane: a molecular dynamics study
Published in Phase Transitions, 2022
Yan Zhou, Wanquan Wang, Shukun Zhang, Peng Sun, Yan He
As early as 2012, adding carbon nanomaterials to improve the thermal conductivity and morphological stability of PCM has received widespread attention. Shi [19] et al. adopted graphene and exfoliated graphite nanoplatelets (xGnP) to improve the thermal conductivity and shape-stabilization of paraffin PCM. The physical properties of CPCM of two carbon nano additives were prepared and compared in experimental studies. The results show that 10 wt% of xGnp can increase the thermal conductivity of paraffin/xGnp CPCM by up to 10 times. However, the improvement in thermal conductivity of paraffin/graphene CPCM is comparably small. Huang [20] et al. compared the effects of graphene and graphene oxide additives on the thermophysical properties of paraffin by MD simulation. From the vibration power spectrum of paraffin, graphene and graphene oxide, it was found that there is vibration coupling between paraffin, graphene and graphene oxide in the middle- and low-frequency region. The thermal conductivity of paraffin/graphene oxide is higher than that of paraffin/graphene due to their larger molecular vibration couplings.
Phase change material infiltrated 3D porous carbon interconnected composites for thermal energy storage
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Rabia Sattar, Tehmeena Ishaq, Anam Afzal, Rubina Mukhtar, Asima Naz
Exfoliated graphite (EG) produced from the natural flakes of graphite with the H2SO4 intercalation at industrial level has different usages like in gaskets and seals (Chen and Chung 2013; Xia, Zhang, and Wang 2010). The compression of complete exfoliated graphite led toward self-standing compact foams of EG can be used in different applications of great interests. Proposed illustration of graphite/PCM composite is described in Figure 3. Porosity of this carbon foam is strongly dependent upon exfoliation temperature. The exfoliation at low temperature leads to lower porosity (incomplete exfoliation). On the other hand, thermal conductivity of EG foam strongly depends upon the bulk density of this carbon foam which is independent to exfoliated temperature (Pasupathy and Velraj 2008; Py, Olives, and Mauran 2011). The composites of montmorillonite (MMT)/PCM were prepared by adding exfoliated graphite nanoplatelets (xGnP) in order to improve thermal conductivity for energy storage (Jeong et al. 2013). Similarly, the paraffinic Na-MMT/PCM composites combined with xGnP are also reported with the improved thermal conducting properties of PCMs. The process of vacuum impregnation for the incorporation of xGnP was used which guarantees of high heat storage capability of PCMs due to surface tension and capillary force during process of incorporation without alternating their chemical properties attributing to minimize the leakage loss (Jeong et al. 2015).
Spectroscopic ellipsometry studies on optical constants of crystalline wax-doped asphalt binders
Published in International Journal of Pavement Engineering, 2022
Haopeng Zhang, Qingshan Xie, Haibo Ding, Ali Rahman
Ultraviolet–Visible (UV–Vis) spectrometer can measure reflectance and absorbance spectra of materials with the aid of an integral sphere (Park et al. 2021; Yu et al. 2012). The absorbance spectra of exfoliated graphite nanoplatelets (xGNP) modified asphalt binder was measured by the UV–Vis spectrometer at different wavelengths (Yao et al. 2016). The results showed that the xGNP modified asphalt binder absorbed more radiation and energy, which can be used to enhance the self-healing effects or accelerate self-healing at high temperatures. The UV–Vis spectrometer was also employed to measure the reflectance spectra of the asphalt binder with thermochromic microcapsules (Hu and Yu, 2016). The thermochromic asphalt binder can effectively reduce the surface temperature of asphalt pavement. On this basis, the sasobit was added to the thermochromic asphalt binder (Chen et al. 2021), and the results revealed that the added sasobit could largely reduce the mixing and compaction temperatures of the thermochromic asphalt mixture by 16°C.