Polymer Blends in an External Pressure Field

Besides temperature and polymer composition, pressure is a third parameter needed to completely determine the thermodynamic equilibrium state of a binary mixture. So far, only a few systematic SANS studies exist for polymer blends in external pressure fields [34-41]. Those experiments were also performed in our laboratory for which a temperature-pressure cell was developed for in-situ investigations allowing pressure and temperature fields between 0.1 P(MPa) 200 and - 20 T(°C) 200, respectively. A temperature control better than 0.01 K allowed also precise exploration of thermal composition fluctuations near the critical point [34]. 

The SANS data near the critical point were analyzed with the corresponding crossover functions (Eqs. 15-19) and the effect of pressure was mainly 

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