PRELIMINARY ANALYSIS OF THE PSEUDO-SOLID ECHOES OBSERVED BY NMR METHOD IN SOME POLYMERIC SAMPLES

The relaxation of the transverse magnetization of the protons attached to polymeric chains and pseudo-solid echoes were observed for molten polyizobutyl and for polyizobutyl-C7D8 solutions by NMR method, in a large temperature domain. The analysis of the shape of the pseudo-solid echoes leads to the possibility of evaluating the function that characterizes the contribution of the fluctuation of the entanglements to the relaxation of the transverse magnetization. The modification of this function is associated to the perturbation of the superposition property of the relaxation curves and induces changes of the properties of the pseudo-solid echoes.