Papers by Keyword: Paraffin

Paper TitlePage

Authors: Yue Li Wen, Wei Huang, Bin Wang
Abstract: A simple and novel preparation method for Cu nanoparticles has been suggested in this work. Its main innovative thought lies in preparing nano-copper in liquid paraffin without addition of other reductant. The paraffin is cheap and nontoxic, and the copper nanoparticles prepared by this method are not oxidized when exposed to air at room temperature. The obtained nano-copper has been characterized by X-ray diffraction measurements (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and energy dispersive analysis of X-ray (EDX), X-ray photoelectron spectra (XPS), and Fourier transform infrared spectroscopy (FTIR). The TEM results confirm that the optimal average size of nanoparticles is about 20 nm. The effects of time, temperature and surfactant on the size of nano-copper have been investigated. The results show that the optimized conditions are reaction temperature of 250 oC and reaction time of 3 h. By this method, the raw materials are cheap and the process is simple, so it can be applicable to large-scale production of copper nanoparticles.
906
Authors: Wei Xia, Heng Xue Xiang, Wen Ping Chen, Yan Li, Wei Chen, Li Jun Chen, Jie Zhao, Mei Fang Zhu
Abstract: Cellulose is a good bio-based material for rich resources and recyclability. Paraffin is widely used in the field of energy storage and temperature regulation due to its excellent heat storage properties and mature preparation technology. In this paper, the cellulose fibers with energy storage and temperature regulation were prepared by wet spinning process using paraffin as phase change material. Field Emission Scanning Electron Microscope (FE-SEM), X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) were utilized to characterize the morphology structure, crystalline properties, phase transition properties and heat resistance of fibers and so on. The results showed that the fiber surface without holes and paraffin was uniformly distributed in the cellulose matrix, and paraffin was not easily overflow during the process of phase change. Paraffin and cellulose substrate had good compatibility due to the interaction of hydrogen bonding, and 30% of paraffin did not cause a significant impact on the degree of crystallinity and thermal stability of cellulose fibers. Enthalpy of the resultant functional fibers could reach 27.44 J/g, and the thermal decomposition temperature was over 300 °C. The fibers possessed the phase change ability and certain mechanical properties. Furthermore, it was found that the fibers still had good resistance to washing under extreme conditions.
2318
Authors: Liang Zhao, Rui Ying Ma, Xiang Lan Meng, Gang Wang, Xiang Chen Fang
Abstract: Paraffin and modified inorganic porous materials composites as phase change energy storage materials were prepared by absorbing paraffin in porous network of inorganic materials. In composite materials, paraffin was used as phase change material (PCM) for thermal energy storage, and γ-Al2O3 acted as supporting material, ethanol was solvent. A series of characterization were conducted to analyse and test the performance of the composite materials, and differential scanning calorimeter (DSC) results showed that the PCM-3 composite has the melting latent heat of 115.9 kJ/kg with melting temperature of 63.0°C. Due to the capillary and surface tension forces between paraffin and γ-Al2O3, the leakage of melted paraffin from the composites can be prevented. Several kinds of paraffin mixtures were also studied by adsorbing into the supporting materials, so that the composite energy storage materials with different phase change temperature can be used in the building wall to storage thermal of different regions. In a word, the paraffin/γ-Al2O3 composites have a good thermal stability and can be used repeatedly.
1419
Authors: R. Meenakshi Reddy, K. Krishna Reddy, E. Siva Reddy, T. Hariprasad
Abstract: The purpose of thermal energy storage systems (TES) is to store the heat energy supplied to it for a considerable time period and give the energy back when ever need arise. On many of occasions, part of the heat energy of various systems is unutilized. If this excess heat energy be stored in such systems as TESS, utilization of energy improves. If the use of such systems is widespread, fuel is conserved and national economy is saved.Different materials can be used in TESS to store heat energy and in the present work two such materials, which are popular phase change materials (PCM) namely (a) Paraffin (b) Stearic acid are used and subsequently the performance of the TESS is studied. The PCMs are used in the form of spherical capsules made up of high density poly ethylene (HDPE) of diameter 58 mm. Charging time and amount of heat energy recovered are studied for the two PCMs mentioned above and compared. Though paraffin as PCM gives little better heat energy recovery, performance of both the materials are almost the same. Hence as the cost of stearic acid is less when compared to paraffin on economical grounds and on ease of availability basis stearic acid has advantages over paraffin.
88
Authors: Wu Sheng Luo, Sheng Fei Yu, Jie Min Zhou
Abstract: In this paper, paraffin/polyurea (PU) phase change microencapsules were prepared through an interfacial polymerization method using composite paraffin with solid/liquid mass ratio 3:7 as core materials, 2,4 toluene diisocyanate (TDI) and ethylenediamine (EDA) as monomers, NP-10 as an emulsifier. It was explored the effect of the monomer mass ratio mEDA: mTDI on the yield of hollow PU microcapsules, and the effect of core/shell ratio on the particle size and coating efficiency and storage-energy performance of paraffin/PU phase change microencapsules. The experimental results showed the PU yield is increasing with the increasing of EDA:TDI mass ratio until 0.5:1,then keeps the constant. Paraffin/PU phase change microencapsules prepared with the core-shell ratio of 2:1 have better performance: the melting point of 28.1°C, the enthalpy of 58.4KJ/Kg, encapsulation efficiency of 87.5%, the average particle size of 4.32μm, and the uniform particle size distribution.
32
Authors: Yong Taeg O, Dong Chan Shin
Abstract: The effects of paraffin addition on the optical properties and crystallinity of selfassembled SiO2 photonic crystal (PC) were examined using a silica nanopowder. The silica nanopowder was fabricated using the well-known Stöber process. During the evaporation process for self-assembly of PC, the nanopowder content was 0.05 or 0.2 wt%, the paraffin addition was fixed to 0.001 wt%, the process temperature was 80oC and the heat-treatment temperature after evaporation was 900oC. The addition of paraffin reduced the defects in the PC layer, thereby resulting in good crystallinity and transmittance. Our results suggested that paraffin can enhance the bonding force between silica nanopowders.
611
Authors: Wu Sheng Luo, Sheng Fei Yu, Jie Min Zhou
Abstract: In this paper, Microencapsulated paraffin/polyurea (PU) phase change materials were prepared through an interfacial polymerization method using composite paraffin with solid/liquid mass ratio 3:7 as core materials, 2,4 toluene diisocyanate and ethylenediamine as monomers, NP-10 as an emulsifier. It was investigated the effects of emulsion speed, the amount of emulsifier and polymerization temperature on the particle size and coating efficiency and storage-energy performance of microencapsulated paraffin / PU phase change materials. The results showed when the emulsion speed is 2000r/min and the amount of emulsifier to core material is 6% and the polymerization temperature is 70°C, Microencapsulated paraffin / PU phase change materials have better performance: the melting point of 28.1°C, the enthalpy of 58.4KJ/Kg, coating efficiency of 87.5%, the average particle size of 3~4μm, and the uniform particle size distribution.
233
Authors: Li Hang Yue, Quan Ying Yan, Zhen Bang Ruan
Abstract: Shape-stabilized phase change materials can store thermal energy and save energy when it is added into the wall. The phase change temperature, latent heat and the stability of shape-stabilized phase change materials with different component were studied experimentally. The critical mass fraction of paraffin required in the materials is given. It is proved that the shape-stabilized phase change material is ideal material used in the phase change wall because it has good stability and uniformity, higher latent heat and suitable phase change temperature.
243
Authors: Gang Li, Kai Pang, Lan Chi, Chang Xiang Liu, Li Jiang, Li Qun Mo
Abstract: In this paper, the author build a new type of Kang with paraffin as its heating surface. Paraffin is a kind of phase change material ,which can stroage and release heat at a relatively constant temperature. It can make full use of the heat of the smoke in the Kang and extend the Kang heating period. We do comparison test of the the traditional Kang room and the phase change Kang room and related temperature was recorded. The tested result shows that the average temperature of the head, medium and tail of traditional Kang varies greatly,the maximum difference of the temperature is over 20°C. While the average temperatures of the head, middle and tail of the phase change thermal storage Kang are 32.59°C, 28.38°C and 26.12°C, Kang surface temperature distribution is more uniform, which improves the comfort of Kang surface. The indoor temperature with phase change thermal storage Kang shows an upward trend after the fuels burnt out until the wee hours. And the average indoor temperature is 1 °C higher than the comparision room. The phase change thermal storage Kang greatly improves the thermal comfort of its heating surface and indoor temperature.
451
Authors: An Liang Zhang, Yan Zha
Abstract: This paper describes the use of a printing circuit technology to generate hydrophilic channels in a filter paper. Pattern was first designed using Protel soft, and printed on a blank paper. Then, the pattern was transferred on a sheet copper using a thermal transfer printer. The sheet copper with pattern was dipped in a ferric trichloride solution to etch the whole pattern of the sheet copper. At last, the etched sheet copper was coated with paraffin, then with a filter paper and heated at the other side of the sheet copper with an electric iron. The melting paraffin penetrated full thickness of the filter paper and formed a hydrophobic “wall”. Colorimetric assays for the presence of protein and glucose were demonstrated in the paper-based device. The work is helpful for researching paper-based microfluidic devices for monitoring health and detecting disease.
211
Showing 1 to 10 of 50 Paper Titles