JOURNAL OF APPLIED POLYMER SCIENCE
·
2016
·Vol. 133
·期 30
·
IF 1.866
Guiming Xie,Pengju Pan,Yongzhong Bao
Evolutions of drop/particle size and size distribution in liquid–liquid dispersions and suspension polymerizations of methyl methacrylate (MMA) were monitored by using an online optical reflectance measurement (ORM), and effects of operating parameters such as the agitation rate, concentration of poly(vinyl alcohol) (PVA) dispersant, and initial concentration of poly(methyl methacrylate) (PMMA) in MMA monomer on the Sauter mean diameter ( d 32 ) and size distribution of drop/particle were investigated. According to the variations of d 32 of drops/particles with time, four characteristic particle formation stages can be identified for suspension polymerization process. The factors that lead to increase the rate of drop break up, such as increasing of concentration of PVA and decreasing of viscosity of dispersed phase, would postpone the particle growth stage. The d 32 and size distribution breadth of drops/particles were significant increased when the liquid–liquid dispersions or suspension polymerizations were conducted at low PVA concentrations or MMA/PMMA solutions with high PMMA contents were used as the dispersed phase, in consistent with the scanning electron micrograph observation on final PMMA particles. It is clear that ORM can be effectively applied in online monitoring of size and size distribution of drops/particles in the liquid–liquid dispersions and suspension polymerizations. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43632.
研究领域:
高分子化学
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化学工程
·
反应工程
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材料科学
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过程监测
✓ 已验证
DOI
高影响因子
Crystals
·
2023
·Vol. 13
·期 10
·1432
·
IF 2.7
Yuke Shen,Shuang Hao,Angqian Suonan,Yanxia Liu,Hangqi Li,Wei Ma,Lin Zhao,Yagang Zhang
Nano-micro calcium carbonate has a small particle size, uniform distribution, and good dispersion performance, offering great research value and development prospects. It has been widely used as a filler material for rubber, paper, ink, pigments, and coatings. Developing an efficient and controllable approach to preparing nano-micro calcium carbonate with adjustable morphology and controllable size has significant economic and environmental benefits. This study reports the controllable synthesis of nano-micro calcium carbonate meditated by additive engineering. The effects of various additives including inorganic acids, organic acids, alcohol, and surfactants on the particle size and morphology of the prepared materials were investigated. SEM, FT-IR and other characterization methods were used to analyze the prepared nano-micro calcium carbonate particle size, dispersion, and uniformity. The results showed that the particle size of calcium carbonate was 4~7 μm with a cubic structure. The particle size of calcium carbonate prepared by adding surfactant additives is in the range of 1~4 μm, and the crystal shape of calcium carbonate changes from calcite to vaterite after adding sodium dodecyl benzene sulfonate. With the aid of additives, the calcium carbonate particles dispersed more evenly. The mechanism of the controllable synthesis of nano-micro calcium carbonate mediated by additive engineering is elucidated and discussed. SDBS was found to be the best additive for preparing nano-micro calcium carbonate, and the synthesis conditions were explored and optimized.Keywords:calcium carbonate;additive;particle size and morphology;energy conservation
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
Journal of the Australian Ceramic Society
·
2019
·Vol. 56
·期 2
·795-801
·
IF 0.692
Zhang Tao,Wei Yaowu,Chen Junfeng,Li Nan
In spite of the advantages of CaO refractories, such as high refractoriness, potential to produce pure steel molten, and high alkaline corrosion resistance, their application has been limited due to its poor hydration resistance. Introducing additives to improve the hydration resistance of lime is a novel method. The influences of Mg(OH) 2 and sintering temperatures on the sintering and hydration resistance of CaO aggregates that were produced by thermal decomposition were investigated in this paper. The purpose of this work was to produce high-purity CaO raw material with high density, low porosity, well grain growth, and good hydration resistance economically. The sintered samples were characterized by bulk density, apparent porosity, surface appearance, and microstructure. The results indicated that (1) Mg(OH) 2 promoted the grain growth of CaO, reduced the apparent porosity, and improved the density of the specimens. The hydration resistance of the samples was increased. (2) Increasing the sintering temperature improved the hydration resistance of the specimens obviously in the experiment. (3) Grain size of CaO was more uniform with the increment of Mg(OH) 2 content, and the density of the compacts was improved.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Yuhui Chen,Zhenhua Hao,Rulong Ma,Pei Wang,Yongchun Shu,Jilin He
In this study, a new unmixed carbon reduction method was proposed for the preparation of pure W powder. The effects of reduction temperature, reduction time, carbon distance and thickness of WO 3 layer on the phase of the reduction products were investigated. Results show that pure tungsten powder with a carbon content of less than 150 ppm can be prepared at 950 °C with a WO 3 layer thickness of 5 mm and a carbon distance of 2 mm. Increased carbon distance and thickness of WO 3 layer will lead to a decrease in the reduction ratio. Additionally, particle size of the tungsten powder gradually increases from 1 μm to 8 μm due to sintering with the extended reduction time. Furthermore, a two-stage carbon reduction process with WO 2 as an intermediate product is proposed, which avoids the sintering and growth of tungsten powder particles and the particle size of tungsten powder was successfully reduced to 2 μm. This unmixed carbon reduction reduces the carbon concentration and prevents the carbonization of tungsten powder. The experiment verifies the feasibility of carbon as a reducing agent in producing pure tungsten powder by reducing WO 3 .
研究领域:
材料科学
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2018
·Vol. 98
·期 2
·422-429
·
IF 1.745
Shaoqiang Zhang,Dong Tian,Geng Zhang,Lin He,Hua Zheng,Jun Hu,Yi Li,Minxia Liu,Yaohua Hu,Wei Zhang
Abstract The peculiar magnetic properties of superparamagnetic iron oxide nanoparticles (SIONs) have spurred great interest in their potential application in enhancing medical images and drug delivery. Currently hindering the application of nanomagnetic particles in these fields is due to SIONs nonuniform size distribution, agglomeration, non-crystallinity, and low magnetic moment. In this paper, magnetic nanocrystals of different sizes and morphologies were prepared by the solvothermal method, which utilized an n-hexane-surfactant system with Fe(acac) 3 and iron-powder precursors. The crystalline structure and particle size of grown SIONs are characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). HRTEM showed that the SIONs were approximately 5.6–6.8 nm in size with no agglomeration and a uniform distribution. Within the reaction time, HRTEM also confirmed that the shape and nanocrystals of SIONs had changed from an irregular crystal shape to triangles and quadrilaterals, and finally to hexagonal nanoparticles. According to the test results of the magnetic properties test and the literature, the material that has been synthesized is a superparamagnetic material. And the maximum saturation magnetization was 62.65 emu/g, which is reported among the largest magnetic properties of SIONs at a size of 6.8 nm.
Superparamagnetic Fe 3 O 4 nanoparticals with different size and morphology were prepared by solvothermal method in N-hexane-surfactant system with the precursors of Fe(acac) 3 and iron powder. With the increasing reaction time and under the regulation of the surfactant molecules, the morphology and nanocrystals of SIONs have initially changed from the irregular crystal to triangles and quadrilaterals shape, and finally to the hexagonal nanoparticles.
研究领域:
生物医学工程
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纳米材料科学
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磁性材料
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药物输送系统
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2016
·
IF 4.509
Fei Li,Zhiguo Xia,Quanlin Liu
Controlled synthesis of absorber materials Cu2ZnGeS4 (CZGS) has been performed using different Ge precursors, including GeCl4 and the self-synthesized Ge complexes with Ge-glycolic acid (denoted as Ge-Gly), Ge-tartaric acid (denoted as Ge-Tar), and Ge-citric acid (denoted as Ge-Cit). The grain size of as-prepared CZGS nanocrystals (NCs) is dependent on the Ge precursors. All four Ge precursors enabled the wurtzstannite CZGS phase formation. The Ge-Cit precursor led to the formation of monodispersed NCs owing to the fact that the undissolved metal-Cit complex in OLA absorbed the small CZSG NCs and avoided the irregular crystalline behavior. The other three precursors induced two different sizes, and the corresponding reaction mechanism has been proposed. Moreover, the Cu2ZnGe1–xSnxS4 NCs with different Ge/Sn ratios were prepared using the Ge-Cit precursor, verifying the general effect on the phase formation and selective grain sizes. The compositional effect on the band gap variation and morphologies of Cu2ZnGe1–xSnxS4 was also studied.
研究领域:
材料科学
·
化学合成
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 12
·9167-9175
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IF 2.22
Cai Wei,Zhang Qianwei,Zhou Chuang,Gao Rongli,Zhang Shilong,Li Zhendong,Xu Ruicheng,Chen Gang,Deng Xiaoling,Wang Zhenhua,Fu Chunlin
Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O 3 (BCZT) ceramics with various grain sizes were fabricated through solid-state method followed by different sintering temperatures. The influences of grain size and phase structure on the electric properties and energy storage performance were systematically investigated. The remnant polarization and quasi-static piezoelectric constant of BCZT samples increase gradually as grain size increases, and the samples with the grain size of 44.37 µm exhibit excellent ferroelectricity and piezoelectricity (2 P r = 25.4 µC/cm 2 , d 33 = 513 pC/N). Although the energy storage density of BCZT samples with the grain size of 8.28–44.37 µm is relative lower, all the ceramic samples have higher energy storage efficiency (82–87.4%). There is the maximum energy storage density in phase transition temperature of tetragonal–cubic phase for all BCZT ceramics and the maximum energy storage density first increases and then decreases with the increase of grain size. But the energy storage density of BCZT ceramics near room temperature decreases with increasing of grain size. The smaller grain size is beneficial to improve the room temperature energy storage density of BCZT samples and is disadvantageous to obtaining superior ferroelectric and piezoelectric properties.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 22
·5655
·
IF 3.1
Tianyu Hao,Jing Shen,Qiaochu Peng,Jie Liu,Wenbin Hu,Cheng Zhong
This study successfully synthesized high-tetragonality barium titanate (BaTiO3) particles with a small particle size by implementing ball milling in the solid-state synthesis of BaTiO3and utilizing nanoscale raw materials. This study also addressed the issues of impurities and uneven particle size distribution that could exist in the synthesized BaTiO3particles. The crystal structure, morphology, and particle size of the synthesized BaTiO3particles have been meticulously analyzed and discussed through the use of techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and the laser particle size analyzer. BaTiO3has been successfully synthesized, exhibiting a uniform particle size with an average diameter of 170 nm and a high tetragonality value of 1.01022. This new solid-state synthesis method provided insights to avoid the impact of “size effects” during the process of electronic device miniaturization.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2019
·
IF 3.25
Zepeng Lv,Dong Liu,Yijie Wu,Run Zhang,Haibo Sun,Jie Dang,Liwen Hu
Tungsten, one of the refractory metals, has lots of excellent properties, making tungsten powders become a choice of raw material for many applications. This work reported a simple method (the salt-assisted hydrogen reduction of WO 3 powders) for preparing tungsten powders with desired morphologies and size. By adjusting the amount of additive (Y(NO 3 ) 3 ) and reduction temperature, metallic tungsten particles with different morphologies and size were obtained. It was found that both temperature and additive had apparent effects on the morphology and size of metallic W particles, and the large parallelepiped-shaped powders disappeared and large irregular blocky-shaped powders were degraded under the influence of additive. With the increase of temperature and amount of salt, particles became more dispersed and the size increased at higher temperatures, and the shape of particles was changed from spherical to polyhedral as well. On the contrary, the size of sub-particles became smaller as increasing amount of Y(NO 3 ) 3 at lower temperatures. Based on the results, the reaction and refining mechanisms for preparing tungsten were proposed as well.
研究领域:
材料科学
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
Inorganic and Nano-Metal Chemistry
·
2019
·
IF 0.685
Xiuzhao Yin,Lingna Liu,Jihui Yang,Zifei Peng,Yuxiang Yang
Red nanofluorescent materials based on Y2O2S: Eu3+ were prepared by the molten salt method. Multiple small-sized Y2O2S sphere-shpaed particles ranging from 100 nm to 200 nm were prepared using different types of yttrium salts (Y(NO3)3·6H2O, YCl3, Y2(CO3)3·3H2O and Y2(C2O4)·6H2O). Based on a fluorescence performance test, their fluorescence properties reached up to 275 nm. We chose NaCl-Na2CO3 as the molten salt, and with all other experimental parameters being equal, the Y2O2S:Eu3+ particles produced were more uniform, with better diffraction properties and a smoother surface. With a molar ratio of 30 for molten salt and yttrium salt, more spherical Y2O2S:Eu3+ particles were produced small and sand homogeneous size. By using different dosage of molten salt, it was found that higher dosage of resulted in smaller particles with weaker fluorescence properties. Finally, by comparing the molten salt method with production by solid-state reaction, we found that the luminescence intensity of the product increased 20％compared to products obtained with the solid-state reaction.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Guoqiang Luo,Ganrong Zhang,Luo Bai,Ying Zhang,Yuxin Fan,Yuzhe Han,Xiaoping Guo,Meijuan Li,Rong Tu,Qiang Shen
Tetragonal BaTiO 3 (BT) powder with appropriate size and dispersity is essential for the dielectric layers in multilayer ceramic capacitor technology. In this work, high tetragonality BT powder with controllable dispersion, and particle size was synthesized using combined dispersants and a two-step hydrothermal method . Owing to the synergistic effect of chemical bond force and electrostatic adsorption force between cetyltrimethylammonium bromide (CTAB) and polyvinyl-pyrrolidone (PVP) composite dispersants at a high temperature, the ultrafine BT powder with a high c/a of 1.0090, small size of 236 ± 15 nm and low polydispersity index of 0.336 was achieved. This idea shows great significance for the synthesis of BT powder with high tetragonal, high dispersion, and small particle sizes.
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
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Kui Liu,Kuibao Zhang,Ting Deng,Jianjun Zeng,Baozhu Luo,Haibin Zhang
Gd 2 Zr 2 O 7 ceramic is considered as one of the most promising host minerals for the immobilization of high-level radioactive wastes . Here, the effects of grain size on the aqueous durability of Gd 2 Zr 2 O 7 ceramics were studied. Two kinds of leaching experiments were used to research Gd 2 Zr 2 O 7 ceramic powders and bulks with different grain sizes (5 nm, 78 nm, 1 μm and 18 μm). The results demonstrate that the normalized leaching rates decrease with the increase of grain size. Through characterization and analysis, it is concluded that the hydrolysis reactions of Gd 2 Zr 2 O 7 occur in the leaching experiment and the hydrolysates are Gd(OH) 3 and Zr(OH) 4 . Besides, all the samples after leaching exhibit slight lattice contraction, which decreases with the increase of crystal grain size. The influence of leaching on the elemental distribution is most significant for the sample with grain size of 5 nm. This study has theoretical guiding significance for the application of Gd 2 Zr 2 O 7 immobilization.
研究领域:
材料科学
·
核废料管理
·
环境化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）