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991.
Zirconia nanoparticles were encapsulated by polyethylene via a polymerization compounding method using a Ziegler-Natta catalyst. The chemical reaction was carried out in an organic solvent under moderate pressure of ethylene monomer. Transmission electron microscopy (TEM) indicated the presence of a thin layer of polymer, about 6 nm, uniformly applied around the particles. However, the thickness of coating layer can be controlled as a function of time and operating conditions of the process. The morphology study using scanning electron microscopy (SEM) as well as TEM revealed that although the nanoparticles seem to be coated individually, some agglomerates, encapsulated by a polymer film, could be observed. The grafting of the catalyst to the original surface of particles was further confirmed by X-ray photoelectron spectroscopy (XPS). 相似文献
992.
993.
Aurélie Alba Aurélia Schopp Anne‐Paula De Sousa Delgado Roland Cherif‐Cheikh Blanca Martín‐Vaca Didier Bourissou 《Journal of polymer science. Part A, Polymer chemistry》2010,48(4):959-965
The bis‐sulfonamide m‐C6H4(SO2NHPh)2 efficiently promotes the ring‐opening polymerization of lactide when combined with tertiary amines, such as N,N‐dimethylaminopyridine. Polylactides of controlled molecular weights (Mn up to 17,700 g mol?1) and very narrow molecular weight distributions (Mw/Mn < 1.11) are obtained under mild conditions and in a living fashion. The reaction takes place through a bifunctional mechanism involving activation of both the alcohol and the monomer. Modulation of the sulfonamide component supports cooperative dual hydrogen‐bonding of lactide involving the two (SO2NHAr) moieties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 959–965, 2010 相似文献
994.
A rotating bomb calorimeter belonging to the Laboratory of Chemistry and Process Engineering (UCP) at ENSTA ParisTech since
the 1960s was modernized and re-set in order of service for the measurement of heats of combustion of sulphur-containing compounds.
The parts of the calorimeter that were replaced concerned essentially the thermal regulation, firing system and data acquisition,
while most of the mechanical organs were found to work perfectly. The apparatus was tested extensively and calibrated using
standard benzoic acid. The standard energy of combustion of thianthrene was measured to validate the operating protocol for
sulphur compounds. 相似文献
995.
Alexander P. Kharitonov Galina V. Simbirtseva Vyacheslav M. Bouznik Maxim G. Chepezubov Marc Dubois Katia Guérin Andre Hamwi Hayat Kharbache Francis Masin 《Journal of polymer science. Part A, Polymer chemistry》2011,49(16):3559-3573
Chemical–physical properties of ultra‐high‐molecular weight polyethylene (UHMWPE) treated by direct fluorination, direct fluorination accompanied with UV irradiation, by XeF2 and by TbF4, were tested by FTIR spectroscopy, visible spectroscopy, 19F and 13C NMR, scanning electron microscopy, XRD, and EPR. Surface energy measurements were carried out. The direct fluorination of UHMWPE is a diffusion‐controlled process, but treatment with XeF2 is a kinetically controlled one. Direct fluorination and direct fluorination accompanied with UV irradiation results mainly in a formation of ? CF2? groups. On the contrary, ? CHF? groups are prevailing in UHMWPE treated with XeF2 and TbF4. Surface texture of UHMWPE treated with XeF2 and with F2 is quite different. Direct fluorination results in a higher polarity of the polymer surface when compared with treatment with XeF2. For the case of direct fluorination, both long‐lived peroxy and fluoroalkylradicals are formed. For the case of treatment with XeF2, only fluoroalkylradicals were detected. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49:3559–3573, 2011 相似文献
996.
997.
Andreas N. Baumann Felix Reiners Dr. Alexander F. Siegle Dr. Peter Mayer Prof. Dr. Oliver Trapp Dr. Dorian Didier 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(27):6029-6035
Thiete dioxide units have been employed as a template for further functionalization through C−H activation strategies. Using simple thiete dioxide building blocks, a new library of axially chiral molecules has been synthesized that owe their stability to electrostatic interactions in the solid state. Similar starting materials were further engaged in the formation of cyclic trimeric structures, opening the pathway to unprecedented macrocyclic ring systems. 相似文献
998.
999.
We propose an algorithm to estimate the motion between two images. This algorithm is based on the nonlinear brightness constancy
assumption. The number of unknowns is reduced by considering displacement fields that are piecewise linear with respect to
each space variable, and the Jacobian matrix of the cost function to be minimized is assembled rapidly using a finite-element
method. Different regularization terms are considered, and a multiscale approach provides fast and efficient convergence properties.
Several numerical results of this algorithm on simulated and experimental geophysical flows are presented and discussed. 相似文献
1000.
Duy‐Khiet Ho Xabier Murgia Chiara De Rossi Rebekka Christmann Antonio G. Hüfner de Mello Martins Marcus Koch Anastasia Andreas Jennifer Herrmann Rolf Müller Martin Empting Rolf W. Hartmann Didier Desmaele Brigitta Loretz Patrick Couvreur Claus‐Michael Lehr 《Angewandte Chemie (International ed. in English)》2020,59(26):10201-10201