Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 23: Polymer Dynamics

CPP 23.4: Vortrag

Mittwoch, 24. März 2010, 11:00–11:15, H48

The role of the intermolecular magnetic dipole-dipole interaction in low frequency proton NMR in polymer melts. — •Nail Fatkullin¹, Anvar Gubaidullin¹, Siegfried Stapf², and Rainer Kimmich³ — ¹Kazan State University, Kazan 420008, Tatarstan, Russia — ²Technische Universität Ilmenau, Dept. Technical Physics II, 98684 Ilmenau, Germany — ³University of Ulm, Sektion Kernresonanzspektroskopie, 89069 Ulm, Germany

The different contributions to the dynamic magnetic dipole-dipole correlation function, which is responsible for proton NMR phenomena like the spin-lattice relaxation, the free induction decay, the solid echo, etc.,, are analyzed. For the anisotropic tube-reptation model the relative weight of the intra-molecular contribution in the time dependent magnetic dipole-dipole correlation function should progressively increase with time, corresponding to lower resonance frequency, compared to the intermolecular contribution. For the isotropic n-Renormalized Rouse model the situation is opposite: with increasing of time/decreasing frequency the relative weight of the intermolecular contribution progressively increases and may eventually dominate. Theoretical estimations and analyses of published experimental results, connected with proton NMR spin-lattice relaxations in polymer melts, directly show that at times longer than and at frequencies below the regime, neglecting the intermolecular contributions to proton NMR phenomena in polymer melts, as had been done in the majority of scientific papers, is incorrect.