A critical evaluation of model-fitted and observed H-1 NMR spin-lattice relaxation time data (T-1) of methylaluminoxane (MAO) dissolved in toluene suggests that the relaxation time of MAO is predominantly controlled by rotational motions. Within the Al concentration (C-Al) range (10(-3) M T > 20 degreesC) studied, the diffusion of MAO contributes with less than 20 (at the maximum concentration investigated) to the overall relaxation rate. For concentrations smaller than 0.5 M, the diffusion has no significant impact on the spin-lattice relaxation time (), the activation energy of the diffusion process-((11.2 +/- 0.7) kJ/mol), and the temperature/concentration dependence of the viscosity of the MAO solution. References: 38
展开▼
