Chemical potential, segment-molar

The term RT (In r j,)/r has been combined with the segment-molar chemical potential Ab(Mi, M2, M,) of the pure species... 

With the help of Eq. (10.12), all thermodynamic quantities necessary for liquid-liquid equilibria calculations can be obtained. One important quantity is the segment molar chemical potential jii of a component i present in the mixture. This quantity can be obtained by derivation of Eq. (10.12) with respect to the segment number of moles of the considered compound. For the segment chemical potential of the polymer, it can be found with xa = 1 — xb ... 

So, the tangent to the curve of the molar variable at composition point x intersects, on both vertical axes x = 0 and x = 1, two segments whose lengths are respectively the values of the corresponding partial molar variables for the chosen composition. This method of determining the chemical potentials is called the tangent method. 

Here, the phase equilibrium condition for the copolymer holds for all polymer species within the total segment number and chemical composition range of the system. This equation is valid for the total interval of the values of the identification variables r and y found in the system. Replacing the segment-molar chemical potentials for the solvents in (7) according to (2) and rearranging results in ... 

The activity coefficients in (9) can be derived using standard thermodynamics in combination with (5). The replacement of the segment-molar chemical potential of the copolymer species in (7) according (4) leads to ... 

IX Segment-molar chemical potential r Gamma function... 

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