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51.
Styrene/N-cyclohexylmaleimide copolymers with small polydispersities and controlled molecular weights were synthesized by a free radical copolymerization using an iniferter system consisting of benzoyl peroxide and 2,2,6,6-tetramethylpiperidine-N-oxyl. Due to the interactions of the electropositive (styrene) and electronegative (N-cyclohexylmaleimide) monomers the brutto polymerization rates are higher than for other living polymerizations initiated with the same iniferter system. The prepared copolymers were used as macroiniferters for bulk polymerization of styrene. 相似文献
52.
Summary: 1-Vinylimidazole is grafted onto Poly(ethylene-alt-tetrafluoroethylen (ETFE) by means of pre-irradiation technique with electron beam doses between 50 and 150 kGy. The degree of grafting is significantly increased to values of up to 115% by addition of 20-50 mmol/L of an Fe2+ salt that facilitates the decomposition of the peroxide structures within the irradiated films. The obtained mechanically stable and flexible ETFE-graft-poly(1-vinylimidazole) membranes exhibit a homogenous distribution of the graft polymer for degrees of grafting greater than 50 wt.-% and show thermal stability up to 250 °C. The applicability of these membranes as anhydrous proton conducting material when doped with phosphoric acid and the complexation capability for Cu2+ ions is demonstrated. 相似文献
53.
Summary: The analysis of the influence of ionic liquids (ILs) in polymer synthesis as an alternative for common organic solvents is still an active field of research. 1 Using ILs as solvents for free radical polymerizations implies a significant increase in polymerization rates and molecular weights which can be observed. In this work we examined the copolymerization behaviour of styrene (S) and methyl methacrylate (MMA), glycidyl methacrylate (GMA) and 2-hydroxypropyl methacrylate (HPMA) with acrylonitrile (AN) in 1-etyhl-3-methylimidazolium ethylsulfate ([EMIM]EtSO4). ILs are liquids with comparable high polarities and viscosities. These two characteristic properties are strongly correlated with the rate coefficients of propagation kp and termination kt. 2 - 4 The rate constant of termination kt decreases when the IL concentration and therefore the viscosity of the reaction mixture is increased, whereas the propagation rate coefficient kp increases with increasing IL content. The viscosity of the IL can be varied by either working with mixtures of IL with conventional organic solvents – here the IL [EMIM]EtSO4 was mixed with DMF – or by variation of the temperature. The influence of the viscosity of the IL ([EMIM]EtSO4) on polymerization kinetics of methyl methacrylate (MMA) and styrene/acrylonitrile (S/AN) was investigated. 相似文献
54.
Höhn P Auffermann G Ramlau R Rosner H Schnelle W Kniep R 《Angewandte Chemie (International ed. in English)》2006,45(40):6681-6685
55.
Lutz Grotjahn Ronald Frank Gudrun Heisterberg-Moutsis Helmut Blöcker 《Tetrahedron letters》1984,25(47):5373-5376
Negative ion FAB-MS is recommended for the rapid routine identification of monomeric as well as oligomeric building blocks used in the phosphotriester synthesis of DNA fragments. 相似文献
56.
57.
J. Petzold 《Annalen der Physik》1981,493(6):451-460
Foundation of a Functional Equation of Motion for the Radiating Electron II: Non Linear Approximation The radiation reaction of an extended, classical particle is analysed in 3rd order approximation. From this we obtain a relativistic equation of motion, in structure similar to the one given in part I. But there are differences in the relation between the charge distribution and the kernel of the integro-differential equation. 相似文献
58.
Armin Petzold 《Fresenius' Journal of Analytical Chemistry》1956,149(4):258-263
Ohne Zusammenfassung 相似文献
59.
Bernd Gerlach Dieter Gromes Joachim Petzold 《Zeitschrift für Physik A Hadrons and Nuclei》1969,221(1):53-70
By comparing the structure of the particle current and of the energy and momentum density, the meaning of the various tensor components is clarified. We decompose the energy momentum tensor into two parts. The one describes orbital, the other spin properties. 相似文献
60.
Dawid Kot Gudrun Kissinger Markus Andreas Schubert Max Klingsporn Andreas Huber Andreas Sattler 《固体物理学:研究快报》2015,9(7):405-409
In this work, we investigated the stoichiometry of oxygen precipitates in Czochralski silicon wafers. The thickness dependence of the Cliff–Lorimer sensitivity factor for the silicon/oxygen system was determined and applied for the investigation of the stoichiometry of oxygen precipitates by EDX. The results show that both plate‐like oxygen precipitates and a transitional form between plate‐like and octahedral precipi‐ tates consist of SiO2. This was confirmed by EELS low loss spectra where the typical spectrum for amorphous SiO2 was observed. Moreover, the absorption band of plate‐like precipitates at 1227 cm–1 was found in the low temperature FTIR spectrum. It was demonstrated that this band can only be simulated by the dielectric constants of amorphous SiO2. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献