Chemorheology and Kinetics of High‐Performance Polyurethane Binders Based on HMDI

Author(s):  
Beatriz Lucio ◽  
José Luis de la Fuente
Keyword(s):  
2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruirui Wang ◽  
Renbing Wu ◽  
Chaofan Ding ◽  
Ziliang Chen ◽  
Hongbin Xu ◽  
...  

AbstractThe practical application of lithium–sulfur batteries is severely hampered by the poor conductivity, polysulfide shuttle effect and sluggish reaction kinetics of sulfur cathodes. Herein, a hierarchically porous three-dimension (3D) carbon architecture assembled by cross-linked carbon leaves with implanted atomic Co–N4 has been delicately developed as an advanced sulfur host through a SiO2-mediated zeolitic imidazolate framework-L (ZIF-L) strategy. The unique 3D architectures not only provide a highly conductive network for fast electron transfer and buffer the volume change upon lithiation–delithiation process but also endow rich interface with full exposure of Co–N4 active sites to boost the lithium polysulfides adsorption and conversion. Owing to the accelerated kinetics and suppressed shuttle effect, the as-prepared sulfur cathode exhibits a superior electrochemical performance with a high reversible specific capacity of 695 mAh g−1 at 5 C and a low capacity fading rate of 0.053% per cycle over 500 cycles at 1 C. This work may provide a promising solution for the design of an advanced sulfur-based cathode toward high-performance Li–S batteries.


2020 ◽  
Vol 4 (4) ◽  
pp. 1747-1753 ◽  
Author(s):  
Yuanyuan Ma ◽  
Wenjie Zang ◽  
Afriyanti Sumboja ◽  
Lu Mao ◽  
Ximeng Liu ◽  
...  

Hollow structuring of active components is an effective strategy to improve the kinetics of oxygen electrode catalysts, arising from the increased the active surface area, the defects on the exposed surface, and the accessible active sites.


2015 ◽  
Vol 48 (3) ◽  
pp. 827-835 ◽  
Author(s):  
Mingliang Tang ◽  
Xuerun Li ◽  
Yusheng Shen ◽  
Xiaodong Shen

Modeling of the kinetics of the synthesis process for calcium sulfate α-hemihydrate from gypsum formed by flue gas desulfurization (FGD) is important to produce high-performance products with minimal costs and production cycles under hydrothermal conditions. In this study, a model was established by horizontally translating the obtained crystal size distribution (CSD) to the CSD of the stable phase during the transformation process. A simple method was used to obtain the nucleation and growth rates. A nonlinear optimization algorithm method was employed to determine the kinetic parameters. The model can be successfully used to analyze the transformation kinetics of FGD gypsum to α-hemihydrate in an isothermal batch crystallizer. The results showed that the transformation temperature and stirring speed exhibit a significant influence on the crystal growth and nucleation rates of α-hemihydrate, thus altering the transformation time and CSD of the final products. The characteristics obtained by the proposed model can potentially be used in the production of α-hemihydrate.


2020 ◽  
Vol 42 (4) ◽  
Author(s):  
Nguyen Mai Lan

Polycyclic Aromatic Hydrocarbons (PAHs) in aircraft soot are capable to distribute in the gas phase and particulate phase in chemical transformations in the atmosphere. The desorption of PAHs from the soot surface is a preliminary step in the study of the reactivity of particulate PAHs. The desorption kinetics of PAHs are measured from soot samples to determine desorption rate constants for different PAHs as a function of temperature and the binding energies between PAHs and soot. The kinetics of degradation of particulate PAHs were studied in the flow reactor. The soot samples previously deposited on a Pyrex tube are introduced into the reactor along its axis and the concentrations of PAHs adsorbed on soot are determined by the High-Performance Liquid Chromatography (HPLC) as a function of the desorption time. The results show a correlation between the size of PAHs and the thermodynamics of desorption: with the PAHs have the same number of carbon atoms, their energies of desorption are very similar and increase with this number. The activation energies EA and the number of carbon atoms in PAHs have a linear correlation. It is consistent with the additivity of the laws Van der Waals. The similarity between the activation energies of desorption of PAHs and the corresponding sublimation enthalpies is consistent with the similarity between the graphitic structure of soot and the structure of PAHs.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
A. El Yadini ◽  
H. Saufi ◽  
P. S. M. Dunlop ◽  
J. Anthony Byrne ◽  
M. El Azzouzi ◽  
...  

Supported titanium dioxide (TiO2) was investigated for the photodegradation of the insecticide fenamiphos in water. The photocatalyst was immobilised on borosilicate glass plates and the kinetics of degradation were studied in a stirred tank reactor under UV irradiation. Two types of TiO2, for example, Millennium PC500 (100% anatase) and Degussa P25 (80% anatase, 20% rutile), were used. Their activities have been based on the rates of insecticide disappearance. Experiments were investigated to evaluate the effect of pH and initial concentrations of fenamiphos as well as catalyst doses on the photocatalytic degradation of fenamiphos. Kinetic parameters were experimentally determined and an apparent first-order kinetic was observed. For photolysis process of fenamiphos, two photoproducts were identified and characterized using high performance liquid chromatography/mass spectrometry (HPLC/MS). The plausible mechanism of photolysis involved is the oxidation of sulfonamide group. In presence of photocatalyst TiO2, photodegradation was observed. Under identical conditions, Degussa P25 shows higher photocatalytic activity in regard to PC500 Millennium and complete degradation was observed after 180 min.


Author(s):  
junsheng lin ◽  
Yangcheng Mo ◽  
Shiwen Li ◽  
Jie Yu

Under high sulfur loading, high sulfur content and low electrolyte/sulfur ratio (E/S), the practical application of lithium sulfur (Li–S) batteries is seriously limited by the negative and slow kinetics of...


Author(s):  
GYUMIN KIM ◽  
Eun Seo Oh ◽  
Ajay Kumar Jena ◽  
Tsutomu Miyasaka

Controlling the evaporation kinetics of the perovskite precursor (EKP) during the thermal annealing step of organic–inorganic hybrid perovskite solar cells (OIHPs) is important for achieving high performance. Although regulation of...


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