Handbook of Solvents - George Wypych - ChemTech - Ventech!

324 V V Tereshatov, V Yu. Senichev, E Ya Denisyuk
Figure 6.2.7. Dependence of equilibrium swelling of
PBU on the ϕ 2 value for TBP in the liquid phase (1)
and the φ 2 value in the gel (1�) swollen in the mixture:
nonane-TBP.
fraction ϕ2 of component 2 in a liquid phase
and on the volume fraction φ2 of component
2 of SL that is a part of the swollen gel. The
data vividly show that extremum swelling
of crosslinked elastomers in SL can be observed
in all investigated cases. At the maximum
value of QV, the compositions of SL
in the liquid phase and in the swollen elastomer
practically coincide (ϕ2 ≈ φ2).
The total sorption can be determined
by the total content of the mixed solvent in
the swollen skin 9 or in the swollen elastic
network (these results). The dependencies
of QV on ϕ2 (Figures 6.2.5-6.2.8) reveal the
influence of liquid phase composition on
the total sorption. The total sorption of the
binary solvent by polymer can also be measured
by the value of the volume fraction of
polymer in the swollen gel 9 Figure 6.2.9. Experimental dependence of the preferential
sorption ε on the volume fraction ϕ 2 of component 2
in the liquid phase: 1-DOS(1)-DEP(2)-PBU(3), 2-hexane(1)-DBP(2)-PBU(3),
3-hexane(1)-DBM(2)-PBU(3),
4-amyl acetate(1)-DMP(2)-SCN-26(3), 5-nonane(1)
-TBP(2)-PBU(3).
because the
value of υ 3 is unequally related to the volume
fraction of the absorbed liquid,
υ3 = 1−
( υ1+ υ2).
At the fixed total sorption (QV or υ 3 = const) the preferential sorption, ε,
can be found from the following equation:
ε= φ1 − ϕ1 = ϕ2 −φ2
Figure 6.2.8. Dependence of equilibrium swelling of
crosslinked elastomer SCN-26 on the ϕ 2 value for
DMP in the liquid phase ( 1) and the φ 2 value in the gel
(1�), swollen in the mixture: amyl acetate-DMP.