En solution aqueuse les polyvinyle pyridines quaternisees par des bromures d'alkyles normaux A longue chaine sont susceptibles de former des micelles. Cette propriete a CtC mise en evidence par solubilisation d'hydrocarbures et de colorants' , 2 a 7 3 ) , v i~c o s i m~t r i e ' "~~*~" ) et diffusion de la l~m i k r e '~,~' . La relaxation nucleaire convenant particulikrement A 1'Ctude de la dynamique de ces macromolecules en solution a ete appliquee aux polyvinyle-4 pyridines, (PV4P), quaternisees par l'acide bromhydrique (PV4PH') ainsi que par des bromures d'alkyles normaux comportant 2 A 10 carbones (1 I x I 9), de formule generale (n = degre de polymerisation, q = taux de quaternisation): -CH -CH 4 Les mesures du temps de relaxation TI ont et6 effectuees en transformee de Fourier A 25MHz pour I3C, 100 et 250MHz pour 'H, sur des PV4P atactiques (avec les triads mm = 5 %, mr = 35 %, rr = 60%) de masse molkculaire 1601
The association constant for the charge transfer complex between maleic anhydride and vinyl acetate was obtained from NMR measurements. The most probable conformation of the complex was investigated with PCILO calculations which showed that the most stable geometry is a "sandwich" form. The electronic structure of the complex was deduced from CNDO/2 calculations. The calculated charge distributions and the observed variation of 13C NMR shifts agree with each other. The relative reactivity of each isolated monomeric molecule, and of the complex in radical alternating copolymerization, has been discussed qualitatively in terms of frontier orbitals.
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