GPC Measurements in Various Solvents

Theory of gel permeation chromatography. Mechanism of separation and the influence of polymer-sorbent interaction

“…A similar observationwas reported on changing from chloreform to DMF (13) and from tetrahydrofUran to DMF (14). Methyl ethyl ketone and DMF (a = 0.60 -0.64) are poor solvents for polystyrene, and in GPC separations with these eluents the plot of log hydrodynamic volume versus VR for polystyrene is displaced to high VR with respect to a plot for,another polymer for wnich these same eluents are good solvents (13,15). Similar results have been reported for polystyrene at 35°C in the thetasolvent cyclohexane (15,17,18).…”

“…Methyl ethyl ketone and DMF (a = 0.60 -0.64) are poor solvents for polystyrene, and in GPC separations with these eluents the plot of log hydrodynamic volume versus VR for polystyrene is displaced to high VR with respect to a plot for,another polymer for wnich these same eluents are good solvents (13,15). Similar results have been reported for polystyrene at 35°C in the thetasolvent cyclohexane (15,17,18). Thus, cyclohexane is a good solvent for polyisoprene and poly(dimethyl siloxane) which follow the same plot of log [n]M versus VR' whereas the plot for polystyrene is displaced to much higher VR values (17,18), These results have been successfully represented by equations(l6) and (17) as shown in Figure 1.…”

“…DMF is a poor solvent for linear polystyrene with a values between 0.60 and 0.64. Consequently, deviations from the universal calibration J • V • DAWKINS plot of hydrodynamic volume for crosslinked polystyrene gels have been observed with organic eluents having a in the range 0.5 -0.7 and values of 6 either less than or greater than that for polystyrene (10)(11)(12)(13)(14)(15)(16)(17)(18)(19). In one of the first attempts to show that GPC Separations with porous glass were size dependent (20), the plot of log polymer size versus VR was influenced by eluent polarity.…”

“…The deperidence of polymer-sorbent interaction on polymer~solvent interaction may be studied with eluents having about the same polarity, in the absence of specific eluent -adsorbent interactions.. For single liquids as eluents with e: 0 in the range 0.40 -0.56, deviations from the universal plot of log hydrodynamic volume veraus VR have .been reported for polystyrene in poor solvents (15,16). Otocka and Hellman (16) Their plot of log hydrodynamic volume veraus V suggested that the poorer the solvent for the polymer, e.g.…”