Chemical relaxation methods preparation

We have already discussed the possibility of changes in fractional free-volume being related to the physical structure of polymers. To show this in greater detail, a special study was made102. Hie viscoelastic properties and relaxation time spectra were studied in a filled system where a powder of hardened epoxy resin was used as the filler and the same epoxy resin as the matrix. Thus the system was identical from the chemical point of view, the only difference being in die method of preparation. 

This section discusses 3D-SPRITE which has been shown to be successful for studying short relaxation time systems and which is free from distortions due to susceptibility variations for coals with high resolution at a frequency of 400 MHz.55 The results obtained are discussed in relation to the three-dimensional distribution of the mobile component for two kinds of coal, Witbank and Goonyella. At the same time, inversion recovery preparation experiments (7 mapping), T2 mapping and T mapping based on SPRITE methods are presented in order to clarify the chemical heterogeneity of coals. 

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