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
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 136
·期 21
·47552
·
IF 2.188
Dong Xu,Rui Yang
Microencapsulated phase-change materials (MEPCMs) with paraffin as the core and poly(methyl methacrylate) (PMMA) and PMMA copolymers as the shell were prepared by emulsion polymerization using redox initiators at low temperatures. Fourier transform infrared spectroscopy was used to characterize the chemical composition of MEPCMs. The thermal properties and thermal stabilities of MEPCMs were tested by differential scanning calorimetry and thermogravimetric analysis. The morphologies and sizes of the microcapsules were investigated by scanning electron microscopy and particle size distribution analysis. The results indicated that the yield of microcapsules is as high as 96.2%, and the encapsulation efficiency of paraffin is nearly 100% when the paraffin content in MEPCM is 70%. The MEPCMs have good stability: the leakage ratios of MEPCMs can be less than 1% after 50 heating–cooling cycles. Therefore, the microencapsulation of paraffin using redox initiators has good production and application prospects. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47552.
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
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 17
·15241-15248
·
IF 2.324
Ma Xiaochun,Liu Yanjun,Liu Han,Xu Bin,Zhou Jing,Xiao Fan
In this study, the microencapsulated phase change material with paraffin as core and inorganic TiO 2 shell was successfully synthesized by in situ hydrolysis and polycondensation of tetrabutyl titanate in a nonaqueous oil-in-water emulsion using formamide as aqueous phase. The chemical compositions, crystalline structure, morphology and microstructure of paraffin@TiO 2 microcapsules were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal properties and thermal stability of the microcapsules were measured by differential scanning calorimeter (DSC) and thermo-gravimetric analyzer (TGA). FT-IR and XRD results proved that there was no chemical reaction between paraffin core and TiO 2 shell material. SEM images indicated that the paraffin@TiO 2 microcapsules showed a regular spherical shape with the average diameters of 2–5 µm with a smooth shell. SEM and TEM studies also confirmed the paraffin was fully encapsulated with TiO 2 . DSC analysis indicated that the microcapsules had similar phase change behaviors as those of pure paraffin. Typical sample froze at 52.24 °C with a latent heat of 110.42 J g −1 and melt at 60.41 °C with a latent heat of 107.54 J g −1 , of which the encapsulation ratio achieved to 54.58%. TGA results indicated the thermal stability of paraffin was improved by the protection of TiO 2 shell through the encapsulation.
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
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 24
·25107-25116
·
IF 2.914
Liu Guanghua,Lin Guanquan,Lin Xida,Zhou Hongjun,Chen Huayao,Hao Li,Zhou Xinhua
The overdosage use of pesticide was harmful to the environment and human health, which was mainly caused by the low utilization rate of the pesticide. However, the pesticide microcapsule with sustained-release and stimulating response properties could effectively solve this problem. Preparation of carboxymethyl cellulose grafting dimethyldiallylammonium chloride (CMC-g-PDMDAAC) through grafting polymerization and trapping as well as encapsulation of avermectin (AVM) via electrostatic interactions resulted in the formation of AVM/CMC-g-PDMDAAC microcapsules. The results showed that the particle size was 200~300 nm. The encapsulation efficiency was as high as 72.06%. Furthermore, the remaining rate of encapsulated AVM increased from 50.0 to 81.60% after UV irradiation for 359 min. The microcapsules exhibited significant enzyme and pH stimuli responsiveness. Finally, CMC-g-PDMDAAC had no significant difference effect on the toxicity of AVM, AVM could be found, and DMDAAC featured a synergistic effect on the toxicological effects of AVM.
Graphical abstract
研究领域:
农药科学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE
·
2019
·Vol. 56
·期 3
·1095-1103
·
IF 1.85
Zhang Baodong,Huang Chongxing,Zhang Linyun,Wang Jian,Huang Xingqiang,Zhao Yuan,Liu Ying,Li Cuicui
In this study, fresh mangos were packed using a custom-made antimicrobial film coated with sustained-release chlorine dioxide microcapsules. We then compared physical and chemical indexes, such as weight loss rate, firmness, chromatic aberrations, soluble solids, vitamin C, titratable acid, and other nutritional indicators, to examine changes in the mango and film during storage. Our findings revealed that control mango showed loss of edible value and commercial value after 21 days of storage, and the chlorine dioxide microcapsule antibacterial film group still retains food value and commercial value. Cross-sectional scanning electron microscopy images of the used film showed that the polylactic acid film was smooth and flat, whereas cross-sections of the antimicrobial film showed that the film was covered with voids due to deliberate release of chlorine dioxide gas during the packaging process. Thus, the antibacterial film exhibited erosion and degradation. These findings provided important insights into the use of antimicrobial films for the packaging of fruits during storage, which is essential for promoting the application of solid chlorine dioxide antimicrobial film in packaging preservation.
研究领域:
食品科学
·
生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2017
·
IF 2.714
Kai-di Cui,Bei-xing Li,Xue-ping Huang,Lei-ming He,Da-xia Zhang,Wei Mu,Feng Liu
Sustained-release profile is an important component in the quality control of microcapsules. In the current study, we propose a reliable, convenient, and versatile strategy to assess the controlled-release performance of MCs under artificial, simulated conditions. Dissolution tests were performed using an experimental device equipped with syringe filters. The optimum experimental conditions utilized 80% v/v methanol (3 ml) as a release medium at each sampling point, Nylon 6 filters (13 mm diameter, 0.22 μm pore size) as diffusion barriers, and a sampling regime based on predetermined changed intervals. Validation tests demonstrated that this strategy possessed favorable universality for three wall materials (polyurea, polyurethane and urea-formaldehyde) and three core materials (phoxim, pyraclostrobin and clomazone), as all sampling points had standard errors below 3.4%. Our proposed method also showed apparent advantages in experimental precision and the demand for a release medium compared with dynamic dialysis.
研究领域:
药剂学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 59
·53949-53954
·
IF 3.289
Qingqing Rao,Kunlin Chen,Chaoxia Wang
Superhydrophobic surfaces have attracted tremendous attraction because of their novel aspects of surface physics and important applications ranging from self-cleaning materials to microfluidic devices. However, most artificial superhydrophobic surfaces easily lose their superhydrophobicity under natural sunlight irradiation, physical rubbing or organic contamination. Here, fluoroalkyl silane (FAS)-loaded microcapsules, photocatalytic TiO2 nanoparticles and FAS modified SiO2 nanoparticles were mixed with waterborne polysiloxane resins to obtain waterborne self-healing superhydrophobic coatings. Superhydrophobic surfaces were formed by casting the coatings on the substrates after UV-irradiation and could sustain their superhydrophobicity even after 360 h accelerated weathering test. Meanwhile, the coating was durable enough to withstand water blasting and the attacks of strong acid or basic solutions without apparently changing its superhydrophobicity. More importantly, after being mechanically damaged or contaminated with organics, these coatings could restore their superhydrophobicity under UV light. All these characteristics ensure that the coatings have excellent long-term superhydrophobicity for outdoor service.
研究领域:
材料科学
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER BULLETIN
·
2016
·Vol. 74
·期 2
·359-367
·
IF 1.371
Wei Kun,Ma Biao,Wang Hainian,Liu Yu,Luo Yu
A series of novel epoxy polymer shell microcapsules with n -tetradecane and dimethylbenzene as binary core materials are successfully synthesized via interfacial polymerization. Dimethylbenzene is used as the solvent for epoxy and n -tetradecane. The chemical structure, surface morphology, and thermal properties of the microencapsulated phase-change materials (micro-PCMs) are characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscope. Results show that the micro-PCMs have relatively spherical profiles and smooth surfaces with diameters ranging from 10 to 70 μm. The epoxy shell successfully encapsulates the binary core. Phase-change enthalpy and binary core content in the micro-PCMs increase with the increasing mass ratio of the binary core to the epoxy resin. The micro-PCMs degrade in two steps, and the resulting microcapsules exhibit good thermal stabilities. The degradation temperature decreases, as the core-to-shell mass ratio increases.
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
Scientific Reports
·
2018
·Vol. 8
·期 1
·1-11
·
IF 4.122
Zhuang Xueheng,Zhang Ying,Cai Chang,Zhang Jing,Zhu Yuejin
Magnetic microencapsulated phase change materials (magnetic MicroPCMs) are hotly researched for their dual-functions with phase change and magnetic properties, which provided the new applications in fields of maneuverable phase change materials and infrared electromagnetic dual shield. A series of magnetic MicroPCMs samples are synthesized by polymerization and coprecipitation method and the chemical composition contained poly(MMA-MAA) @ n-octadecane modified by Fe 3 O 4 . In addition, the characterizations exhibit the excellent magnetic and phase change properties. The magnetic MicroPCMs samples present 20 emu·g −1 saturation magnetization with still high enthalpy of 132 J·g −1 , which fully illustrates that the magnetic MicroPCMs fulfill both application on thermal energy storage and magnetic control.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2013
·
IF 3.379
Fuli Feng,Rongrong Li,Qingyun Zhang,Yinsong Wang,Xiaoying Yang,Hongquan Duan,Xinlin Yang
The reduction-triggered degradable poly(methacrylic acid- co - N,N -bis(acryloyl)cystamine)/polyethyleneimine (P(MAA- co -BAC)/PEI) microcapsules were prepared by distillation–precipitation polymerization for delivery of anti-cancer drug and gene. N,N- bis(acryloyl)cystamine (BAC) as a crosslinker containing a disulfide bond can be triggered by reductive agents, such as glutathione (GSH) and dithiothreitol (DTT), to endow the functional microcapsules with reduction-triggered drug release. The P(MAA- co -BAC)/PEI microcapsules were characterized by transmission electron microscopy (TEM), Fourier-transform infrared spectra (FT-IR), laser particle size analyzer and elemental analysis . The degradable behavior of microcapsules was investigated by analysis of UV-vis spectroscopy. The controlled drug release behavior for P(MAA- co- BAC)/PEI microcapsules was strongly dependent on the absence/presence of GSH and the pH values with doxorubicin hydrochloride (DOX) as a model drug molecule. The in vitro gene transfection ability was evaluated by Hela cells with the transfection of plasmid DNA (pDNA) encoded with green fluorescent protein (GFP) and the transfection efficiency was determined by confocal fluorescence microscopy . Furthermore, the cytotoxicities of (P(MAA- co -BAC)/PEI) microcapsules before and after loading of DOX were assessed via WST-1 assay. The P(MAA- co -BAC)/PEI microcapsules provide the potential novel vectors for delivery of drugs and genes, promising for future applications in anticancer drug and gene combined therapy.
研究领域:
生物医学工程
·
药剂学
·
分子生物学
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2021
·
IF 5.161
Shupei Liu,Chijia Wang,Kaka Li,Zihua Wang,Hongxin Luo,Weihao Fan,Huaiyuan Wang
Anti-scaling is a key challenge in various industrial productions. The use of coatings is the most effective strategy for protecting metal equipment. An excellent scale inhibitor is 1-hydroxy ethylidene-1, 1-diphosphate (etidronic acid) (HEDP), which is usually incorporated into wastewater and discharged directly with the water flow. In this study, HEDP was coated with poly-α-ethyl cyanoacrylate (PEC) by a simple spray method. The corresponding slow-release microcapsules, which we named PEC&HEDP, were successfully prepared. In addition, a correct mass of the microcapsules was added to the spray polyurea elastomer (SPUA) coating. The resulting SPUA/PEC&HEDP 70&30 composite coating exhibited excellent anti-corrosion and scale-inhibiting effects. Electrochemical impedance spectroscopy and salt spray corrosion test were used to assess the corrosion resistance of the coating. The results showed that the barrier performance of the composite coating improved significantly. In addition, the scale inhibition performance of the composite coating was tested in a supersaturated CaCO 3 solution. The results showed that the scale inhibition rate of the composite coating was higher by as much as 80.5% relative to the pure SPUA coating. This work provides a new and simple method for designing and preparing a slow-release microcapsule composite coating intended for scale control.
研究领域:
材料科学
·
腐蚀与防护
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Energies
·
2022
·Vol. 15
·期 15
·5354
·
IF 3.252
Hongbing Chen,Rui Zhao,Congcong Wang,Lianyuan Feng,Shuqian Li,Yutong Gong
In this paper, a new type of microencapsulated phase change materials (MPCMs) with docosane as the core and titanium dioxide (TiO2) as the shell was prepared by in situ polymerization. Its phase transition temperature was approximately 40 °C, and it can be used as a phase change material (PCM) in a low-temperature solar heat collection system. The properties of the new material were examined including the microstructure, the chemical elements on the surface of the microcapsules, and thermal conductivity. In addition, to obtain the optimized formula of the microcapsules, single-factor analysis on the emulsifier type, its mass fraction, ultrasonic oscillation time, pH, and core–shell ratio were performed. The results showed that the MPCMs prepared in this paper had a particle size of 2–5 μm and were spherical. Its surface was uniform and smooth without cracks, and the TiO2was well dispersed around the docosane, completely coating the docosane without impurities. The MPCMs had good performance in terms of thermal properties and heat storage when using 0.40% SDS as an emulsifier, 10 min ultrasonic, a 3.5 pH value, and a 1:1 core–shell ratio. However, the stirring method, time, and experimental reaction temperature also affected the properties of the material, which was not studied in this experiment. We will continue to study these factors in the future.Keywords:microencapsulated phase change material;core–shell ratio;nanoparticles;thermal property
研究领域:
材料科学
·
太阳能技术
✓ 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）