Development of anisotropy in tar pitches under heat treatment was measured by hot centrifugation and by low field NMR technique through the spin-lattice relaxation time of the hydrogen nucleus (T1H). By using a double exponential model for T1H calculations it was possible to quantify the size of the isotropic and anisotropic domains, suggesting that low field NMR is a suitable technique to address anisotropy in pitches.
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