A STUDY OF THE ADSORPTION PROPERTIES OF R ING-SHAPED MACROMOLECULES IN THE CRITICAL REGION

The behavior of ring-shaped macromolecules at the adsorption critical point and in its vicinity was studied experimentally. The cyclic fract ions with molecular masses 25 000, 77 000, and 126 000 were isolated f rom polystyrene samples obtained by the condensation of bifunctional l iving chains under high dilution and composed of cyclic and linear mac romolecules. The critical conditions for linear polystyrene were deter mined using silica gel columns with wide and narrow pores. In the crit ical region and in its vicinity, where weak exclusion and adsorption e ffects are observed, the behavior of macrocycles was studied. Selectiv e separation of linear and cyclic macromolecules of the same size was achieved when molecular masses were too high. It is shown that the mac rocycles are more strongly retained than the corresponding linear chai ns, and the dependences of the distribution coefficients on the size o f macrocycles are nonmonotonic. Experimental data are compared with th e theoretical predictions for the Gaussian coils and the coils with vo lume interactions.