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Polar effects on the thermodynamic properties of polymer solutions are treated within the framework of the free volume theory. The Sutherland potential and the dipole-dipole interaction are assumed to represent intermolecular interaction in a polar system, with an approximation concerning the radial distribution function. Application of the treatment to some polar systems shows that the theoretical %-parameters are smaller than the observed ones and than the calculated ones without regard to the polarity. The excess volume ratios are, however, nearer to the observed ones compared with those evaluated without the account of the polarity. Therefore, the present results are fairly good for strong polar solutions.