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781.
Wolfgang Jeitschko Dieter H. Heumannskaemper Ute Ch. Rodewald Marietta S. Schriewer‐Poettgen 《ChemInform》2000,31(15):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
782.
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784.
Polyelectrolytes are macromolecules containing dissociable or charged groups. The charge, that is effectively accessible, is determined by counterion condensation, which is strongly influenced by the ionic strength of the solution under study. In general a rapid exchange between free and condensed counterions is expected. In the present study diffusion and electrophoretic mobility of poly(diallyldimethylammoniumchloride) and perfluorinated succinic acid have been monitored simultaneously. Condensation of the perfluorinated succinic acid to the macroion shows in the electrophoretic mobility of succinic acid monitored by pulsed field gradient NMR. In the concentration dependence of the averaged diffusion coefficient and electrophoretic mobility an exchange fast on the time scale of the NMR experiment is manifested. 相似文献
785.
Ute Bergert Sabine Beuermann Michael Buback Caroline H. Kurz Gregory T. Russell Claudia Schmaltz 《Macromolecular rapid communications》1995,16(6):425-434
The choice of the photoinitiator is not usually regarded as being as important consideration in attempting to determine the value of the propagation rate coefficient kp from a pulsed laser-initiated polymerization (PLP). It is shown that in fact the choice of the photoinitiator can profoundly influence the success of such experiments. Specially, for a number of monomers it was found that the successful determination of kp is essentially impossible when 1,1-azodicyclohexanecarbonitrile is employed as a photoinitiator. The likely reason for this phenomenon is discussed from which it would seem appropriate to be wary in using any azo compound as a PLP photoinitiator. From PLP experiments with a non-azo photoinitiator, ambient pressure kp has been determined for bulk polymerization of methyl methacrylate over an extended temperature range. 相似文献
786.
Charles M. Garner Jan Bartus William J. Simonsick Koichi Ute Koichi Hatada Otto Vogl 《Macromolecular Symposia》1992,64(1):167-177
The embryonic state of the ionic methyl methacrylate (MMA) and of trihaloacetaldehyde polymerization was studied. The composition of the oligomer mixtures, the end groups and the stereochemistry of individual compounds of the oligomers was investigated. Depending upon the initiating systems the oligomerization of methyl methacrylate can give either isotactic or syndiotactic oligomers. Trihaloacetaldehye oligomerization is highly dependent on the ceiling temperature of polymerization. The oligomerization of fluoral and chloral is compared with a more detailed study of the bromal polymerization and even more interestingly with the cooligomerization of chloral and bromal. 相似文献