Characterization of Structure and Self-Diffusion of Elastomers by NMR Method
T.P. Kulagina, G.E. Karnaukh, L.P. Smirnov
Institute of Problems of Chemical Physics RAS, Chernogolovka, Moscow region, 142432, Russia
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In this work the theory of free induction decay in linear and cross-linked flexible polymers with a various average length of a polymeric chain in a wide temperature is represented. It is shown the change of topological structure of linear polymers with increasing of mean molecular weight Mw, and at Mw>105 the physical network of entanglements starts being formed. The correlation function of molecular motion which is applied to calculation of diffusion attenuation of spin echo is received. The general approach to calculation of signals of diffusion attenuation spin echo and its application for determination of coefficient of self-diffusion in elastomers with various topological structures is offered. It allowed explanation observed experimentally anomalous diffusion.

DOI: 10.12693/APhysPolA.127.1128
PACS numbers: 76.20+q, 76.60.Lz, 77.84.Jd