Thermal properties of lauric acid filled in carbon nanotubes as shape-stabilized phase change materials

Abstract

Carbon nanotubes (CNTs) filled with lauric acid (LA) as a kind of shape-stabilized phase change material were prepared and their structures and phase change properties were characterized. The results showed that the melting point and latent heat of LA confined in carbon nanotubes were lower than those of the bulk material, and both decrease as the diameters of CNTs and the filling ratios of LA decrease. Molecular dynamics (MD) simulations indicated that LA molecules form a liquid layer near pore walls and crystallize at the pore center. When the LA filling ratio was reduced to a certain value, all LA molecules were attached to the inner walls of CNTs, hindering their crystallization. A linear relationship between the melting temperature shift and structural properties was obtained based on the modified Gibbs-Thomson equation, which gives a reliable interpretation of the size effect of nanochannels in phase change materials. We also found that the thermal conductivity of the composite CNTs/LA was four times larger than that of pure LA. This study will provide insights into the design of novel composite phase change materials with better thermal properties by the selection of suitable porous materials and tailoring their pore structures.

Curding of milk in incubator utilizing latent heat of lauric acid in winter

“…In FTIR spectra, broad stretch is noted in the range 3575 to 2328 cm −1 with two strong peaks around its center, around 2900 to 2800 cm −1 , which is expected to be due to OH stretching from the carboxylic groups of lauric acid. The double peaks at 2917 and 2849 cm −1 are expected to be due to the CH stretching and CH 2 /CH 3 groups of the alkyl chain of lauric acid 16 . A sharp peak at 1701 cm −1 is attributed to characteristic stretching of the C═O present in COOH 18,19 .…”

“…XRD patterns of PCM recorded are shown in Figure 3. XRD patterns of PCM showed two sharp and intense characteristic peaks at diffraction angles (2 θ ) 21.6° and 24°, which corresponds to the (0 0 2) and (1 0 0) lattice planes, respectively, 16,17 which were generated due to the regular crystalline arrangement of the lauric acid.…”

“…Later, 150 g of milk containing culture medium was placed inside TCP box (containing PCM at 50 C) and the efficiency in maintaining fermentation temperature (between 50 C and 30 C) for curd formation was evaluated by exposing to ambient temperature of 1 C. shown in Figure 3. XRD patterns of PCM showed two sharp and intense characteristic peaks at diffraction angles (2θ) 21.6 and 24 , which corresponds to the (0 0 2) and (1 0 0) lattice planes, respectively, 16,17 which were generated due to the regular crystalline arrangement of the lauric acid.…”

Synthesis of Lauric-Myristic Acid/Activated Carbon Composite as a New Shape-Stabilized Energy Storage Material

“…The LA-MA eutectic spectrum shows that there are several main bands at 2917 cm -1 , 2845 cm -1 , 1697 cm -1 , 1471 cm -1 , 1302 cm -1 , 983 cm -1 , and 716 cm -1 . The characteristic spectral bands corresponding to the symmetric and antisymmetric stretching vibration of -CH3 and -CH2 chemical bonds appear at 2917 cm -1 and 2845 cm -1 [17,28]. The absorption spectral band at 1697 cm -1 is produced by stretching vibration of C=O bonds.…”

“…At present, several supporting materials that have received much attention include expanded graphite (EG) [3, 13 -15], carbon nanotubes (CNT) [16,17], expanded perlite (EP) [18,19], activated carbon (AC) [20 -22], expanded vermiculite (EVT) [23] and graphite nanoplate (Gr) [24]. Su et al [25] studied n-octadecane/stearic acid (SA-ODE) eutectic mixture as PCM and hexagonal boron nitride (HBN) was served as support material to manufacture CPCM.…”