JOURNAL OF APPLIED POLYMER SCIENCE
·
2014
·Vol. 131
·期 12
·
IF 1.64
ShaoJun Peng,Yong Jin,Tongbing Sun,Rui Qi,BaoZhu Fan,XinFeng Cheng
A series of waterborne polyurethane dispersions were synthesized by one-pot reaction and step-wise reaction, respectively. The effects of synthetic methods and DMPA content on the particle size distribution (PSD), solid contents and viscosity were studied by laser particle size analyzer, Brookfield viscometer and TEM analysis. High solid content and low viscosity waterborne polyurethanes (WPUs) with controllable bimodal PSD were prepared by one-pot reaction using 2,2-dimethylol propionic acid (DMPA) as the only self-emulsifier. Meanwhile, 40% solid content WPUs with unimodal PSD were obtained by step-wise reaction at the same formula. With the increment of DMPA content, the ratio of large particles to small particles decreased and two peaks of the particle size finally became one peak by one-pot reaction while the PSD remained unimodal by step-wise reaction. The reason leading to the difference of PSD between one-pot reaction and step-wise reaction was analyzed and the relationships among PSD, viscosity and solid content were discussed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40420.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2021
·
IF 9.297
Yong Wei,Guijian Liu,Biao Fu,Ruwei Wang,Yuan Liu,Xuan Xue,Mei Sun
Inhalable fine particulate matter (PM), which is rich in Pb and other pollutants from coal-fired power plants, can cause air pollution and severe health problems. To facilitate the development of efficient techniques for controlling fine particulate Pb emissions, in this study, various types of size-resolved fine PM (<10.0 μm) were collected from the outlets of fabric filter units (FFs) at an industrial circulating fluidized bed (CFB) power plant to assess the distribution and partitioning behavior of Pb. The results showed that the mass particle size distribution (PSD) of the collected fine PM followed unimodal distribution, peaking at 5.8–4.7 μm, which might be caused by the fragmentation of limestone additives and new-formed CaSO 4 . However, the mass PSD of Pb for size-fractionated PM displayed different distribution pattern. Two peaks were observed in the size ranges of 5.8–4.7 μm and 1.1–0.7 μm. The mechanism of Pb enrichment in the supermicron particles was mainly controlled by the surface adsorption reaction, which could be explained by 1/d p dependence and be improved using excess active CaO produced by the injected limestone. For submicron particles, gas-film transfer or heterogenous condensation (mass transfer) might represent the deposition mechanism . Besides Pb enrichment, it was found that the submicron particles (<0.7 μm) mainly consisted of Si-rich and Si–Al phases. The emission of those fine SiO 2 -bearing particles should be limited as they can be inhaled and can damage the respiratory system.
研究领域:
环境科学
·
公共卫生
✓ 已验证
DOI
高影响因子
CRYSTAL RESEARCH AND TECHNOLOGY
·
2024
·Vol. 59
·期 2
·2300264
·
IF 1.5
Hongyan Cui,Liangcheng Song,Sheng Lv,Chongqiang Zhu,Chunhui Yang
Seeding metastable zone of itaconic acid in water is determined using a laser dynamic detecting technique, based on which feedback supersaturation control is performed for the crystallization process. The crystallization is strictly confined within the metastable zone throughout the whole process to effectively inhibit the secondary nucleation and the strategy of seed loading is employed to avoid the burst of primary nucleation, resulting in the uniform particle size distribution. With the aid of solution information, continuous feedback control is conducted to keep the supersaturation at a high level accelerating the crystal growth, which significantly shortens the time consumption, and also the effect of seed amount is discussed in this work.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2013
·
IF 4.63
Yi Wang,Yu Zhang,TianDong Xia,WenJun Zhao,WeiHua Yang
Polymethyl methacrylate (PMMA) encapsulated eicosanoic–stearic acid (EA–SA) eutectic nanocapsules were prepared by ultraviolet photoinitiated emulsion polymerization and various characterization techniques were employed to investigate the influence of preparation methods on thermal properties and particle size distribution (PSD). The results show that the particle size decreased and PSD narrowed with the increase of agitation speed, reduction of initiator and monomer concentration, existence of cross-linking agent and stabilized at agitated speed higher than 5000 rpm and monomer concentration lower than 0.15 mol/L. However, latent heats of the capsules decreased with the increase of monomer and initiator concentration. Type of emulsifier in emulsion has significant effects on PSD and phase change properties of EA–SA/PMMA and nonionic emulsifier is suitable for reducing particle size and enhancing heat storage ability. Morphology and chemical characteristic analysis indicate that spherical nanocapsules with average diameter of 46 nm were successfully fabricated and its maximum encapsulation ratio is 68.8 wt% without leakage of core material. The melting and crystallizing temperatures and latent heats of capsules were determined as 56.9 °C and 54.5 °C, 126.4 J/g and 128.3 J/g, respectively. Accelerated thermal cycling test shows that the nanocapsules have good thermal and chemical reliability after repeated thermal cycling. Besides, the super-cooling problem of PCMs reduced dramatically by forming nanocapsules.
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 CONTROLLED RELEASE
·
2024
·
IF 10.5
Ying Qin,Yi Wei,Zejing Gao,Jingxuan Liu,Donglin Sui,Yuning Hu,Fangling Gong,Guanghui Ma
Sustained release microspheres loaded with goserelin are regarded as a promising candidate for treating prostate cancer and other sex hormone diseases. However, their widespread adoption has been hindered by issues such as wide particle size distribution and unstable release characteristics. To address these challenges, we employed a combination of the solid-in-oil-in-water microspheres preparation approach (S/O/W) and innovative premix membrane emulsification technology and deeply investigated the effects of four key parameters on the loaded performance of microspheres and the microscopic mechanisms behind them. With this approach, we successfully produced goserelin-loaded sustained release microspheres of narrow particle size distribution (Span 0.642), remarkable encapsulation efficiency (DL = 4.23 %, EE = 93.98 %), low initial burst release (about 0.50 % within 2 h), and compatibility with small injection needles (23-G, inner diameter 0.33 mm, outer diameter 0.64 mm, maximal force 59 N). In the animal model(administered dose, 2.4 mg·Kg −1 ), goserelin long-acting sustained release microspheres sustained release for over 32 days, maintaining effective concentrations above 2 ng·mL −1 , and effectively reduced serum testosterone concentrations to castration levels (<1.0 ng·mL −1 ) by day 4, maintaining this inhibition for up to 21 days, exhibiting comparable efficacy to the positive control group. In vivo release kinetics analysis revealed that goserelin-loaded sustained release microspheres exhibited a release pattern dominated by diffusion with corrosion assistance in vivo. In summary, the systematic and comprehensive evaluation of uniform-sized goserelin-loaded sustained release microspheres has highlighted their excellent translational potential, and the study herein may provide new strategies and ideas for the development of microsphere dosage forms.
研究领域:
药剂学
·
生物医学工程
·
肿瘤学
✓ 已验证
DOI
PubMed
高影响因子
Tungsten
·
2024
·
IF 5.6
Peng Qiao-Chu,Hao Tian-Yu,Shen Jing,Liu Jie,Zhong Cheng
Barium titanate was successfully synthesized through both the solid-state method and the oxalate thermal decomposition method. The differences in tetragonality and particle size between the two methods were discussed using X-ray diffraction, scanning electron microscopy, and the laser diffraction method. The elemental content of the impurities ws characterized by an inductively coupled plasma optical emission spectrometer. Meanwhile, the influence of process parameters such as sintering temperature, aging time, and ball milling treatment on the morphology and size of powders was investigated. The results revealed that the oxalate thermal decomposition method could fabricate the BaTiO 3 with a narrow particle size distribution and high tetragonality. Additionally, ball milling treatment offered a significant advantage in reducing particle agglomeration caused by high sintering temperatures and in producing homogeneous BaTiO 3 , which was suitable for industrial production.
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Jianlong Hu,Jiaqing Chen,Xue Zhang,Jianhong Xiao,Shenfa An,Zhiyong Luan,Fan Liu,Baosheng Zhang
The oil-in-water (O/W) emulsions, especially oily wastewater from EOR oilfield, generally contain small oil droplets in the continuous water phase, which is difficult to be removed with conventional oil separation process such as precipitation, flotation. The electrostatic coalescence is a promising pretreatment step to induce the oil droplets coalescence and promote the oil separation efficiency of conventional methods. In order to explore the feasibility of electrostatic demulsification for O/W emulsions, the influence of operating parameters including electric voltage, pulsatile frequency, water content of emulsions and hydraulic retention time (HRT) on oil diameter distribution of the emulsions were studied using dynamic demulsification experiment. The volume percentage of oil droplets with a diameter exceeding 40 μm (denoted as DG40) was adopted as the main indicator of demulsification results, it increased from 0 (the original emulsions) to 65.62% (the treated emulsions) at the optimal operation parameters including water content of emulsions 90 vol%, electric voltage 150 V, pulsatile frequency 1000 Hz, duty cycle ratio 0.5, hydraulic retention time (HRT) 60 s. Furthermore, the water separation efficiency for emulsions reached 82.5% at 11 min of the dynamic experiment duration. The results of this study showed that applying pulsatile electric field could be a feasible and effective technology for emulsified oil droplets coalescence in O/W emulsions.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2015
·
IF 2.358
Shao-Jun Peng,Yong Jin,Xin-Feng Cheng,Tong-Bing Sun,Rui Qi,Bao-Zhu Fan
A new method named two-step emulsification process was developed to synthesize high solid content waterborne polyurethanes by strict control of the bimodal particle size distribution. In the first step, a series of 40% solid content polyester-based (WPU-1) with low content of hydrophilic group and large particle size were firstly synthesized. In the second step, polyether-based prepolymers (WPU-2 prepolymers) with high content of hydrophilic group were firstly prepared and WPU-1 emulsions were used to emulsify WPU-2 prepolymers to obtain the final emulsions with high solid content (WPU-3). The particle size of WPU-3 present bimodal distribution and the diameter ratio and volume percentage of large particles to small particles in WPU-3 were able to be strictly controlled by this method. The viscosity of WPU-3 with 55% solid content was only 489.1 mPa s −1 when the diameter ratio of large particles to small particles was 9.2 and the volume percentage of large particles was 74%.
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
RARE METAL MATERIALS AND ENGINEERING
·
2018
·
IF 0.29
Han Wensong
Cu-Ag particles with different molar ratios have been prepared in the hyperbranched polyester matrix using ascorbic acid as a reducing agent. The third generation hyperbranched polyester has been synthesized by step by step polymerization using the first generation hyperbranched polyester as core molecular and 2, 2-dimethylol propionic acid as branched monomer. The synthesized hyperbranched polyester and Cu-Ag alloy were characterized by FT-IR, 1 H-NMR, UV-vis spectra, X-ray diffraction (XRD), SEM, Energy Dispersive X-ray (EDX), Laser particle size measurement, TEM, etc. The XRD and EDX studies confirm the formation of Cu-Ag alloy. Laser particle size measurement, SEM and TEM studies show that the particles of the Cu-Ag alloy are well-dispersed with average size of 120 nm. The thermal properties of the Cu-Ag alloy have been studied by thermogravimetric Analysis (TGA). The results show that the measurement values are close to the theoretical ones.
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
CRYSTENGCOMM
·
2013
·Vol. 16
·期 8
·1547-1552
·
IF 3.879
Yang Huang,Zanyong Zhuang,Xiaogang Xue,Jinsheng Zheng,Zhang Lin
So far, the photoluminescence (PL) properties optimization of mercaptopropionic acid (MPA) capped CdTe has yet to be understood from a perspective of growth kinetics. In this work, the growth kinetics, size distribution and PL properties of CdTe quantum dots (QDs) grown in MPA aqueous solutions of two extreme concentrations, i.e. 0 mM and 50 mM, were systematically investigated. The studies revealed that CdTe QDs coarsen in low and high concentrations of MPA followed different growth kinetics, i.e. a mixed OA (Oriented Attachment)–OR (Ostwald Ripening) growth and an OA dominated growth, respectively. Moreover, the OR growth in a low MPA concentration solution was found to be disadvantageous for narrowing the size distribution but favourable for enhancing fluorescence, while the OA growth in a high MPA concentration solution is beneficial for focusing and controlling the particle size. Further activation energy calculations indicate that the extra MPA that forbids the OR growth and retards the OA growth is favourable for slowing the particle growth, thus achieving CdTe QDs with a controlled size and narrow distribution. Furthermore, the kinetics study reveals how the introduction of concentrated surface ligands affects the PL properties (FWHM and intensity) of the material.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE CERAMIC SOCIETY OF JAPAN
·
2022
·Vol. 130
·期 5
·341-350
·
IF 1.217
Lu Li,Hongbing Yang,Libin Zhao,Yuanyuan Li,Bing Shen,Masood Mukhtar,Jiangong Li
High-yield production of high-purity, disperse, ultrafine, and equiaxed gamma-alumina (γ-Al2O3) nanoparticles with narrow size distributions are essential for their applications. However, the synthesis of γ-Al2O3 nanoparticles by calcination of alumina precursors usually results in severe aggregates. In our present work, commercial γ-Al2O3 particles with an irregular shape, large size, and severe aggregates were directly ball-milled. The milled powders were subsequently corroded with hydrochloric acid to obtain γ-Al2O3 nanoparticles. The γ-Al2O3 nanoparticles obtained are dispersed without aggregates, equiaxed in shape, and ultrafine with a mean particle size of 6.2 nm. The disperse γ-Al2O3 nanoparticles are with high purity (99.994 %, mass per cent) and yield. Then γ-Al2O3 nanoparticles were separated by fractionated coagulation to narrow their size distribution. After coagulation separations, γ-Al2O3 nanoparticles with mean particle sizes of 4.8, 6.6, and 7.7 nm and respective size distributions of 2–9, 2–12, and 2–15 nm were acquired. This high-yield preparation process for γ-Al2O3 nanoparticles is simple and scaled up. Furthermore, using commercial γ-Al2O3 powders as starting material, disperse, and equiaxed α-Al2O3 nanoparticles with a mean particle size of 7.6 nm and purity of 95.98 % (mass per cent) were also prepared by ball milling at a higher ball-to-powder weight ratio of 60:1 and acid corrosion.
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
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2023
·
IF 3.4
Zhenxing Cai,Gengfei Yang,Hui Zhao,Xiaobo Chen,Chaohe Yang
The morphology and DSC methods were used for measuring the crystallization kinetics of para-xylene. Solubility data from DSC experiments were fitted using the activity coefficient model and classical solid–liquid phase equilibrium theory, while the rates of nucleation, growth, aggregation, and breakage (functions of supersaturation) were built from morphological experiments. The particle size distribution was modeled via a population balance equation and validated by experimental data on a suspension crystallization separation process. The effects of the crystallizer operating temperature and residence time on product yield were also investigated; although the rates of nucleation, growth, breakage, and aggregation increase with decreasing temperature and increasing residence time, the breakage and aggregation are dominant at low temperatures and long residence times. Therefore, the crystallization process should be operated at an optimal temperature and residence time. The models built for this work can be used further in additional process design and optimization.
研究领域:
化学工程
·
材料科学
✓ 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）