Crystallization and Melting Behavior of Erythritol In and Around Two-Dimensional Hexagonal Mesoporous Silica

Abstract

The crystallization and melting behavior of erythritol in and around two-dimensional hexagonal mesoporous silica SBA-15 with a pore diameter range of 7.5-9.2 nm were investigated.Erythritol inside the mesopores did not crystallize but became amorphous when the temperature decreased from 423 K, a value above the fusion point in the bulk, at 1 K min -1 . Subsequently, as the temperature increased at 1 K min -1 , the amorphous cold-crystallized and then fused around 320-360 K. If the temperature decreased from around the fusion point in the mesopores at the same cooling rate, erythritol inside the mesopores become a crystal. The XRD pattern of the erythritol inside the mesopores exhibited the crystal structure at 353 K, suggesting that the crystal grew around the nuclei of crystal. The heterogeneity of mesopores induces partial crystallization or partial melting, resulting in smooth phase transition. However, because the relaxation time of dynamic properties of erythritol confined in mesopores becomes longer due to strong interactions with pore walls, glass transition occurs easily instead of crystallization. The phase transition of erythritol on the outer surface of mesoporous silica particles was also clarified.

Ionic cross-linked polyvinyl alcohol tunes vitrification and cold-crystallization of sugar alcohol for long-term thermal energy storage

“…Although ERY shows a high extent of supercooling, it crystallizes upon cooling within the temperature range −5 to 80°C, depending on the cooling conditions e.g. scan rate, 13,38 as also has been shown in the DSC curves in Fig. 4a.…”

“…4b, CC-PCM (composition C) did not crystallize upon cooling but supercooled until below −20°C when vitrification into a glass occurred. Relaxation time for the dynamic properties of polyol molecules in the PVA matrices is prolonged due to strong intermolecular interactions with the polymer chains; 38 for example, numerous hydrogen bonds between hydroxyl groups on PVA and ERY (Scheme 1) confirmed by FTIR spectra (Fig. 2).…”

Nanoscale Heat Transfer in Carbon Nanotubes - Sugar Alcohol Composite as Heat Storage Materials

“…However, detailed fluctuations are observed, especially when going toward lower CNT diameters. In both materials, the thermal contact conductance across CNT(7,7) is larger than those across CNT (8,8).…”

Preparation and Characterization of Graphene Oxide‐Grafted Hexadecanol Composite Phase‐Change Material for Thermal Energy Storage

“…However, the PCM and shell need matching and appropriate properties,s uch as similar thermal expansibility and different solubility.I na ddition, the synthetic procedure for microencapsulation is complex and expensive. [6] SSPCMs constructed from simplert echnology,b yb lending the PCM with support materials,i ncluding silica, [23] montmorillonite, [24] expanded perlite, [25] and expanded graphite (EG), [26,27] have the features of higher phase-change enthalpy,c onstant shape,g ood compatibility with building materials,a nd the ability to be used directly without extra devices. Unfortunately,t hese SSPCMs still suffer from diffusiono ver time,w hich results in leakage of the PCM.U nlike the methods described above,am atrix-grafted PCM, whichi sa nother kind of SSPCM, is fabricated by grafting moieties of PCM onto supportingm aterials through covalent bonds.D ue to the strong interaction of chemical bonds,t he leakage problem of the solid-liquid PCM is solved.…”

“…In addition, the synthetic procedure for microencapsulation is complex and expensive . SSPCMs constructed from simpler technology, by blending the PCM with support materials, including silica, montmorillonite, expanded perlite, and expanded graphite (EG), have the features of higher phase‐change enthalpy, constant shape, good compatibility with building materials, and the ability to be used directly without extra devices. Unfortunately, these SSPCMs still suffer from diffusion over time, which results in leakage of the PCM.…”