Number of phases present and their miscibility

In general, one can expect four phases in a multiblock PEE, two crystalline and two amorphous. The actual phase structure will depend on the chemical composition and the thermal prehistory of the sample, as well as on the temperature at which the analysis is carried out. The observation of two transition temperatures, T and at about -46 C and 55°C, respectively 

These conclusions are supported also by SAXS measurements performed at various temperatures using synchrotron radiation. The changes in the scattering intensity and the long spacing, L, with temperature and composition were followed [7]. 

These data are supported by the changes in the long spacing with temperature of measurements and composition, too [7]. The observed linearity and reversibility of the L value of homo-PBT [7] means that the changes observed are related solely to the thermal expansion of the samples during the measure- 

This tendency of the amorphous sub-domains to grow is also supported by a decrease in the miscibility of the two amorphous phases (PBT and PEG) with temperature, as suggested by a consideration of the solubility parameters [7]. 

Concerning the number of phases, their transitions and miscibility, as derived on the basis of X-ray and calorimetric studies, it could be concluded 

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