Structural Effects in Polymer Mixtures

Let us discuss in some detail the structural effect which is probably the most unexpected. 

The reduced temperatures of the pure components A and 8 differ only by the values of c/g. We shall always assume that 

Apart from the geometrical effect due to the difference between and rs, the excess functions will now depend on (caI Ia — CBiqs)-The simplest case is a mixture of monomers A and r-mers B then caI a = 1 cbI b- If 5 is a dimer, the number of external degrees of freedom is 5 (3 for the translation of the centre of mass, 2 for the rotation of the molecule as a whole). This gives for z — 12 (cf. 3.5.2) 

Consequently the structural effect due to the external degrees of freedom may play an important role for long r-mers mixed with monomers, or with short r-mers. This is just the situation in high polymer solutions. 

Let us discuss the influence of the external degrees of freedom on the excess flinctions by a graphical method similar to that used in Ch. IX, 4 for mixtures of monomers. 

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Structural Effects in Polymer Mixtures 355. 6. Explicit Expression for... 

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