Polymeric liquid mixtures

Polymeric liquid mixtures are conveniently divided into solutions (containing a low molecular weight liquid) and blends, containing only macromolecu-lar species. They will be briefly described in the following parts, 2.4.1 and 2.4.2, respectively. More detailed discussion of the theoretical foundations is given in Part 2.5. 

By contrast with the mixtures of low molecular weight specimens, where concentration is customarily expressed as a mole fraction, x., that of polymer solution is given either as volume fraction, (()., or (for dilute solutions) wt/vol concentration, c (g/100 mL). In solutions, the solubility originates mainly from the entropic effects — there 

Traditionally, solutions have been used to characterize the polymer — to measure its molecular weight averages, e.g., number, weight and z-average M, M, and M, or the size of its macromolecular coil. The latter maybe expressed as the unperturbed end-to-end distance (six times larger) or the radius of gyration, viz.  

In Eq 2.31 o is the steric hindrance factor of the macromolecular chain, n is number of statistical segments, each of length 1 and with bond angle between two consecutive segments equal to 0. 

The solutions are also used to measure of the thermodynamic interactions between the polymer segments and solvent molecules. The latter is best discussed in terms of the virial coefficients. A.. The change of solvent chemical potential upon dissolution of polymer is given by  

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Curtiss, C. E and Bird, R. B.i Statistical Mechanics of Transport Phenomena Polymeric Liquid Mixtures. Vol. 125, pp. 1-102,... 

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