Browsing by Author "Zhou, Lan"
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- ItemCo-solvent free interfacial polycondensation and properties of polyurea PCM microcapsules with dodecanol dodecanoate as core(Elsevier Ltd, 2020-03) Cai, Changwei; Ouyang, Xu; Zhou, Lan; Liu, Guojin; Wang, Yan; Zhu, Guocheng; Yao, Juming; Militký, Jiří; Venkataraman, Mohanapriya; Zhang, GuoqingA kind of eco-friendly micro-encapsulated phase change materials (MEPCM) with dodecanol dodecanoate as core material were synthesized via the interfacial polymerization of toluene-2, 4-diisocyanate (TDI) and diethylenetriamine (DETA). During the preparation, a facile solvent free synthesis route was developed owing to the good compatibility of TDI and dodecanol dodecanoate. The synthesized MEPCM were characterized by Field Emission Scanning Electron Microscopy (FE-SEM), Particle Size Distribution (PSD) analyzer, Differential Scanning Calorimetry (DSC), Thermogravimetric/Infrared spectrometry (TG-IR) and thermal constants analyzer. It is found that the resultant MEPCM in nearly spherical shape are in the size scope from 10.0 to 40.0 μm, have the average latent heat in the range of 103.4–140.3 J/g, and exhibit high temperature resistance with an onset evaporation temperature at 234.0 °C. Moreover, the MEPCM possess good thermal conductivity from 0.17 W/m K to 0.21 W/m K. Therefore, it is confirmed that the prepared MEPCM can be regarded as a promising thermal energy storage material appropriate to the thermo-regulating fields such as renewable solar heating system.
- ItemPreparation and evaluation of thermo-regulating bamboo fabric treated by microencapsulated phase change materials(2019-08) Zhang, Guoqing; Cai, Changwei; Wang, Yilai; Liu, Guojin; Zhou, Lan; Yao, Juming; Militký, Jiří; Marek, Jaromír; Venkataraman, Mohanapriya; Zhu, GuochengTwo types of microencapsulated phase change materials (ENPCMs) were synthesized by polymerization. The core material of ENPCM was n-octadecane and the shell materials were polymethyl methacrylate-butyl acrylate and polymethyl methacrylate-butyl acrylate-hydroxyethyl methacrylate. Subsequently, the synthesized ENPCMs were applied onto bamboo fabric by the dip and dry method. The properties of ENPCMs were analyzed in terms of surface morphology, size distribution and latent heat; the treated bamboo fabrics were evaluated in terms of surface morphology, hydrophilicity, washing fastness and heat storage capacity. The results showed that polymethyl methacrylate-butyl acrylate/n-octadecane (PMBO) microcapsules had an irregular shape, while polymethyl methacrylate-butyl acrylate-hydroxyethyl methacrylate/n-octadecane (PMBHO) microcapsules were spherical, and the mean diameters of both microcapsules were less than 1 mu m. The latent heat of phase change material (PCM) microcapsules was almost the same at a thermal storage capacity of 110 J/g. There were many more and more even PMBHO microcapsules deposited on bamboo fabric than that of PMBO microcapsules deposited on bamboo fabric. Bamboo fabrics treated by both microcapsules were hydrophilic, and the hydrophilicity of fabric treated by PMBHO microcapsules was even better. The ratio of PCM microcapsules to bamboo fabric was about 1:4, and the latent heat of treated bamboo fabrics was about 20 J/g. Moreover, the treated bamboo fabrics exhibited excellent washing fastness due to the strong binding strength between the highly hydrophilic microcapsules and bamboo fibers. Approximately 72% of PCM microcapsules were retained on the fabric after 15 washing cycles.
- ItemPreparation and Properties of High Thermostability Phase-change Material Microcapsules(2018) Zhang, Guo-Qing; Cai, Chang-Wei; Zhu, Guo-Cheng; Wang, Yi-Lai; Zhou, Lan; Liu, Guo-Jin; Militký, Jiří; Prasad, Mohanapriya; Yao, Ju-MingMicrocapsules containing phase change materials (PCM) are commonly used in many energy storage fields. However, most PCM microcapsules have lower themostability with an onset decomposition temperature of about 150 degrees C, which to some extent restricts their application. In this study, high thermostability PCM microcapsules were synthesized with long chain ester as PCM and PMMA as shell. During the preparation, high chain ester of dodecanol laurate was first synthesized by an esterification reaction under catalysis, then the ester as core material was encapsulated using PMMA by emulsion polymerization. The resultant products were characterized by infrared spectroscopy (IR), differential scanning calorimeter (DSC), thermogravimetry (TG), laser particle size analyzer and scanning electron microscope (SEM). The synthesized dodecanol laurate have a high purity according to the IR spectrum analysis with a suitable phase temperature range of 22-30 degrees C. In addition, the ester also shows good thermal properties with latent heat of 206 J/g, small super-cooling degree of 0.5 degrees C and high thermal evaporation temperature of 220 degrees C, which is very suitable for applying in PCM energy storage materials. Using the above ester as core material, the PCM microcapsules were successfully fabricated by emulsification and polymerization. The prepared microcapsules had a perfect spherical shape with about a diameter of about 865 nm as well as a high heat storage performance with a latent energy of 118 J/g. Due to the high evaporation temperature of the ester core material itself, and with further encapsulation, the prepared PCM microcapsules demonstrated higher thermostability. TG results suggest that the microcapsules have a high onset weight loss temperature of over 252 degrees C due to the encapsulation of PMMA, it is a significant increment when compared to PCM microcapsules reported by most literatures.