COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
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IF 3.99
Rui Xu,Xiaomeng Xia,Wei Wang,Dan Yu
With the rapid development of infrared detection technology and infrared precision guidance of weapons, infrared camouflage has important meanings. Paraffin, a kind of phase change material (PCM) is used as the core material of microcapsules and urea-formaldehyde resin as a shell material to prepare phase change microcapsules (MPCMs) by in-situ polymerization, and then coated on the fabric to get infrared camouflage fabric. Ultrasound cell pulverizer is used for phacoemulsification with short emulsification time to obtain uniform and stable emulsion. The as-prepared fabric was characterized by scanning electron microscopy (SEM), infrared thermal imaging test, thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and temperature change test. The encapsulation ratio of the MPCMs was calculated to be 60.1 %. The average particle size of the MPCMs was 425.7 nm. Compared to unfinished fabrics, infrared camouflage fabrics can reduce temperatures by 5–10 ℃ and so is the infrared emissivity. The results showed that the prepared fabric had a certain degree of infrared camouflage ability since the ability to adjust with temperature changes is significant and infrared heat radiation can be effectively reduced. Based on these effects we believe this study can offer a promising strategy for the preparation of infrared camouflage fabrics both on laboratory and industrial scales.
研究领域:
材料科学
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纺织工程
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 20
·4794
·
IF 4.2
Lin Lin,Ziqi Li,Jian Zhang,Tonghua Ma,Renzhong Wei,Qiang Zhang,Junyou Shi
Phase change energy storage microcapsules were synthesized in situ by using melamine-formaldehyde–urea co-condensation resin (MUF) as wall material, n-octadecane (C18) as core material and styryl-maleic anhydride copolymer (SMA) as emulsifier. Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis were used to study the effects of emulsifier type, emulsifier dosage, core–wall ratio and pH on the morphology and thermal properties of microcapsules. The results show that the pH of core material and the ratio of core to wall have a great influence on the performance of microcapsules. SMA emulsifiers and MUF are suitable for the encapsulation of C18. When the pH is 4.5 and the core–wall ratio is 2/1, the latent heat and encapsulation efficiency of phase transition reaches 207.3 J g−1and 84.7%, respectively. The prepared phase-change microcapsules also have good shape stability and thermal stability.
研究领域:
材料科学
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能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Applied Sciences-Basel
·
2019
·Vol. 9
·期 3
·599
·
IF 2.217
Kai Zhang,Qian Zhou,Hai-Mu Ye
Paraffin, the most common phase change material, has been widely utilized as the core component in thermal energy storage in the form of microcapsules. In this study, semi-crystalline paraffin is capsulated into a poly(urea-formaldehyde) (PUF) shell by a two-step polymerization process. To obtain the microcapsule with good morphology and high latent heat, sodium chloride and crosslinker (a mixture of ammonium chloride and resorcinol with a weight ratio of 1:1) are incorporated and their addition amounts were optimized through differential scanning calorimetry (DSC) and SEM. The optimized microcapsules were obtained by adding 4 wt% sodium chloride, and 0.25 wt% crosslinker exhibits a diameter of several microns and a melting enthalpy of 110 J/g. This detailed study shows that sodium chloride strongly affects the morphology of paraffin emulsion by enlarging droplets, widening the size distribution, and enhancing the stability, which should be attributed to the enhancement of electric double layer strength. In addition, sodium chloride can weaken the Zeta potential of prepolymer and provides more opportunity for prepolymer to deposit on the surface of emulsion droplets. The two components in crosslinker play different roles in the polymerization process. Ammonium chloride reacts with prepolymers and reduces the pH of system, which can accelerate the curing process, while resorcinol probably participates in polymerization as a comonomer.Keywords:Paraffin;Poly(urea-formaldehyde);Phase change microcapsules;Sodium chloride;Crosslinker
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Materials Interfaces
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2022
·Vol. 9
·期 17
·2200541
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IF 6.389
Linfeng Li,Xi Wu,Xiaomeng Zhu,Yuanyuan Li,Liyi Zou,Xiuli Wang,Wenbin Li,Xiaomin Cheng
Conventional plain organic or inorganic shell for microcapsules has their own drawbacks, the organic shell has defects in thermal conductivity and stability; while the compactness and coverage of inorganic shell are not satisfactory. Herein, a novel approach to synthesis of organic–inorganic composite double-layer shell phase change microcapsule (DLSPCM) is proposed, which is achieved by forming inorganic outer shell on the surface of organic shell via atomic layer deposition (ALD). Taking the pristine microcapsule with paraffin core and melamine formaldehyde (MF) shell as an example, MF-ZnO composite double-layer shell (DLS) is formed in this paper. The melting enthalpy of DLSPCM obtained by 100 ALD cycles is 159.7 J g −1 , which is only 12.1 J g −1 lower than that of paraffin @ MF microcapsules (control sample), while the thermal conductivity of DLSPCM surges by 77.8%, and the thermal energy storage ability and thermal regulation performance are basically maintained. After 900 thermal cycles, the heat storage capacity of DLSPCM obtained by 100 ALD cycles decreased by only 3%. Besides, the photocatalytic performance and antibacterial activity of ZnO-reinforced DLSPCM are further confirmed. The successful design of DLSPCM via ALD is prospective for the encapsulation, modification, and reinforcement of phase change microcapsules.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2022
·Vol. 7
·期 33
·e202202124
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IF 2.307
Qingqing Zhang,Zhicheng Sun,Qingwei Guo,Yang Zhou,Zhenzhen Li,Jinyue Wen,Furong Li,Yuanyuan Liu,Shouzheng Jiao
Graphical The combination of photosensitive dyes and phase change microcapsules significantly improves the efficiency of photothermal conversion. The dye converts light energy into heat, which is stored in phase-change microcapsules and released when needed. The heat storage slurry doped with copper phthalocyanine and MXene have the best photothermal conversion performance and are expected to become a novel kind of heat collecting medium. Most solar thermal utilization materials can only absorb ultraviolet irradiation rather than visible-light, limiting the photothermal conversion efficiency of corresponding devices. In this work, a functional thermal slurry system with excellent visible-light absorption and high photothermal conversion performance is developed based on the phase change microcapsules, incorporating the visible-light absorption antenna in the shell structure. Specifically, a phase change microcapsule with paraffin as the core material and silica as the wall material is prepared by the in-situ polymerization method, in which the shell layer is doped with various photosensitive molecules. The photothermal conversion efficiency of copper phthalocyanine and MXene can reach 98 % and 85.3 % respectively. The corresponding conversion efficiency could reach up to more than 80 % in a long temperature range. Therefore, the doping of photosensitive molecules with visible-light absorption can promote the solar energy conversion efficiency of these solar thermal utilization materials.
研究领域:
材料科学
·
太阳能利用
✓ 已验证
DOI
高影响因子
Chemistry-An Asian Journal
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2020
·Vol. 16
·期 1
·102-109
·
IF 4.056
Furong Li,Zhicheng Sun,Shouzheng Jiao,Yutong Ma,Qingqing Zhang,Yang Zhou,Jinyue Wen,YuanYuan Liu
Graphical Electromagnetic shielding has attracted increasing attention for the purpose of safety and health. However, magnetic shielding materials with phase change insulation properties are less reported. Here, dual-functional magnetic phase-change microcapsules for magnetic shielding were successfully prepared with paraffin as the core, melamine-formaldehyde resin as shell, and nano-magnetic particles dispersed in the shell layer through the in-situ polymerization. Using the screen printing technique, the great magnetic shielding role of these microcapsules ink was demonstrated in both static and pulsed magnetic fields on wallpaper. The fabrication of desired anti-magnetic materials for irradiation shielding remains a challenge to date. In this work, a new type of dual-functional magnetic shielding phase change microcapsules with paraffin as the core, melamine-formaldehyde (MF) resin as the shell and doped with magnetic particles in the shell were successfully prepared by in situ polymerization. The magnetic particles were dispersed in the shell layer by coating a hydrophilic emulsifier on the surface. These microcapsules were specifically applied to the field of magnetic shielding by the screen printing method. The effect of magnetic particles on the performance of phase-change microcapsules was examined by differential scanning calorimetry and thermogravimetric analyses. The magnetic type and magnetic strength of the microcapsules were studied by the vibrating sample magnetometer. Moreover, the effects of different magnetic particles (Fe 3 O 4 , CrO 2 ) on the performance of phase change microcapsules and the magnetic strength of microcapsules were compared. The results showed that these two kinds of magnetic particles can greatly improve the phase change latent heat, thermal stability, and thermal conductivity of the microcapsules. Finally, the great magnetic shielding role of these microcapsules was demonstrated in both static and pulsed magnetic fields through the screen printing of magnetic shielding ink on wallpaper. Incorporating 0.5 g Fe 3 O 4 inside of microcapsules, specifically, the magnetic intensity was effectively reduced by ∼250 Oe within a short distance in the static field. We expect that these magnetic microcapsules hold great potential for the shielding of irradiations via the screen printing on various substrates.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Energy Storage
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2023
·
IF 9.4
Liyu Zhang,Xuelai Zhang,Weisan Hua,Zhibo Chen
Phase change microcapsules (MPCM) have significant advantages, such as fast thermal response and low leakage rate, which can be widely used in construction, textile, and electric power fields. However, the existing microcapsule preparation process has high costs and complicated steps, which limits its popularization and application. This paper reports a de-organic reform of the in-situ polymerization method for the fabrication of MPCM. The aqueous phase (solvent) consisted of pure deionized water and surfactant instead of conventional partial or pure organic solvents such as ethanol and acetamide. Taking the type and content of surfactant, homogenization speed, solvent ratio and core-shell ratio as the research variables, the optimal fabrication scheme of silicon-based MPCM in an alkaline environment was confirmed. The results showed that the Pa@SiO 2 microcapsules prepared by pure inorganic solvents had great shape stability to prevent phase change material leakage and great temperature regulation performance when appropriate amount of hexadecyl trimethyl ammonium bromide was the surfactant and 3-Aminopropyltriethoxysilane was the silane coupling agent . More importantly, it has high heat storage capacity of 191.5 J/g due to its excellent encapsulation ratio of 76.4 %. Therefore, the fabrication method without organic solvent can simplify the fabrication process and greatly reduce the fabrication cost while ensuring excellent thermal properties of microcapsules, especially the outstanding heat storage capacity, which shows great application prospects in terms of microcapsule large-scale production.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2022
·
IF 7.139
Suqing Peng,Weilin Zhong,Hailun Zhao,Chao Wang,Zhipeng Tian,Riyang Shu,Ying Chen
Photocatalytic hydrogen production and thermal storage are effective ways to convert solar energy into storable chemical energy and thermal energy , but they only respond to specific spectrum. In order to improve the energy conversion and storage efficiency of solar energy in the solar spectrum, hydrothermal and photo-deposition method were employed to synthesized photothermal catalyst while and Au/TiO 2 @PCM composite microcapsules were fabricated by electrostatic adsorption self-assembly methods. Micro-morphologies and structures were detailed characterized by SEM , XRD , UV-Vis, etc. As calculated from the DSC results for effective, enthalpy value , the loading rates of Au/TiO 2 shell for the microcapsule were 12.6% and 15.4% corresponding to rod-shaped and sheet-shaped samples. To test their catalytic performance, the samples were dispersed in the same concentration of glycerol solution, and showed that the light to hydrogen efficiencies were 11.4‰ and 5.0‰ for ATR@PCM and ATF@PCM, respectively with the increasement of 53.8% and 56.1% comparing to their corresponding catalyst nanoparticle suspensions. Photo-thermal conversion efficiencies of ATR@PCM and ATF@PCM were 62.74% and 53.32% after 60 min-irradiations, and they were 48.22% and 25.96% higher than that of Me-PCM. Therefore, it was confirmed that the composite phase change microcapsules prepared in this study have the dual functions of energy storage and photothermal catalysis. Higher solar light to hydrogen energy conversion efficiency may be attained in future study if the stored thermal energy can be successfully employed to activate organic components for helping catalytic hydrogen generation .
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
CARBON
·
2025
·
IF 11.6
Zhisong Han,Danfeng Du,Fengmei Zhang
Solar energy is an inexhaustible resource. Vigorously developing solar energy can effectively reduce dependence on fossil fuels, thereby improving energy security in countries or regions. However, the application of conventional photothermal materials is limited due to low solar thermal conversion efficiency and the difficulty of preservation. To make use of solar energy, a new phase-change composite material (CNTs-MSA) based on carbon nanotubes (CNTs)-loaded silica aerogel (SA) and microcapsule phase-change materials (MPECMs) was developed by sol-gel and ambient drying. MEPCMs utilize n-octadecane as a phase-change material, which exhibits a enthalpy of 170 J/g and an encapsulation efficiency of 72 %, while also demonstrating stability in retaining their fundamental properties after 200 cycles. Furthermore, the introduction of CNTs not only did not change the lightweight of the aerogel (density is about 0.3 g/cm 3 ), but also greatly improved the compressive strength (the compression stress at 40 % strain reaches 0.9 Mpa). The combination of CNTs and MEPCMs significantly enhanced the solar absorption (14 times than SA) and energy storage capacity (enthalpy of 119 J/g) of the entire composite aerogel material with 75.3 % photothermal conversion efficiency. Such materials will provide a feasible solution to the problem of energy shortage in remote areas, slowing down the over-exploitation of non-renewable energy and promoting environmentally sustainable development.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Xuanxuan Wang,Yuting Wu,Chuan Li,Yuanwei Lu,Cancan Zhang,Ming Hong
As one of classic organic compounds, pentaerythritol (PE) has been reported to have two phase-change processes with one solid-solid transition and other solid-liquid transition. To utilize these two phase-change enthalpies and avoid the liquid leakage over heat storage process, this work for the first time proposes to encapsulate PE with use of silicon dioxide (SiO 2 ) as a shell substance through a so-called so-gel technology. The microstructure characterization and thermoproperties as well as the cycling performance of the PE- SiO 2 composite are detailedly investigated. The results showed that PE could be successfully covered by SiO 2 to form a spherical core-shell structure. Such an encapsulation has a mean size of 0.3 μm and an encapsulated rate of over 77.8 %. Due to the involvement of two phase-transition stages, the latent heat of the PE- SiO 2 composite reached to 255 kJ/kg, which is higher than other organic microencapsulations. In addition, the thermal conductivity is largely enhanced by adjusting the ratio of SiO 2 . For a given SiO 2 ratio of 77.8 %, the thermal conductivity of PE-SiO 2 composite is 0.93 W/m·K, 36.8 % higher than that of pristine PE. Apart from these, the results also indicated that the composite achieves excellent thermal cycling performance. After one hundred repeated heating-cooling cycles, the latent heat of the PE- SiO 2 composite decreases by less than 5 %, demonstrating that this composite material has a large potential for application in the field of thermal energy storage at low and medium temperatures.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Liuwei Chen,Jiayue Lao,Jintao Ma,Zerui He,Wanwan Fu,Jiesheng Liu,Hao Peng,Tao Fang,Yanshu Luo
In this study, a methyl palmitate-polyurea phase change microcapsule (MPCM) was successfully synthesized by interfacial polymerization with methyl palmitate with high latent heat as the core material and tolylene-2,4-diisocyanate (TDI) and diethylene triamine (DETA) as the shell monomers. The effects of emulsifier type and content, cosolvent, reaction rate and core-shell mass ratio on the phase change properties of microcapsules were systematically discussed, and the optimum process was determined. A series of characterization techniques were used to analyze the composition, crystal structure, morphology, microstructure, particle size distribution and thermal performances of the microcapsules. The experimental results presented that the microcapsules synthesized under the optimal conditions had outstanding encapsulation efficiency (72.42 %) and encapsulation rate (70.77 %) with melting temperature and solidification temperature of 27.2 °C and 13.8 °C, and melting enthalpy and solidification enthalpy of 160.5J/g and 157.3J/g, respectively. Moreover, the resulting microcapsules had regularly spherical morphology with compact and smooth surface, and uniform particle size distribution with average particle size of 909.94 nm. Meanwhile, the microcapsules possessed excellent thermal stability, low thermal conductivity (0.2932 W K −1 m −1 ) and excellent thermal reliability. These characteristics made methyl palmitate-polyurea MPCMs have a broad application prospect in the field of thermal insulation.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2020
·
IF 6.984
Honghui Liao,Shengwei Guo,Yuan Liu,Qi Wang
In this work, form-stable phase change composites (PCCs) with high thermal conductivity and adjustable thermal management capacity are prepared based on phase change microcapsules (SiO 2 @SA) and surface-modified boron nitride (m-BN). The phase change properties are successfully infused into PCCs through the incorporation of microcapsules and the thermal conductivity can be elevated up to 0.506 Wm -1 K -1 . Furthermore, the phase change enthalpies of PCCs can be facilely tailored from 3.74 J/g to 18.52 J/g by changing the loading fraction of microcapsule, enabling adjustable thermal energy storage and thermal management ability. PCCs are proved to possess outstanding long-term stability even after 500 cycles of charging-discharging. Besides, practical application of PCCs as thermal regulating materials is explored through a self-designed temperature control system. Finally, the PCCs exhibit good leakage proof property at 100 °C due to the shielding effect of SiO 2 shell. These results show that this work offers a promising strategy for the development of advanced form-stable PCCs with good comprehensive properties.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）