Chemistry Reference
In-Depth Information
Fig. 34 Measured and
calculated phase diagram for
the THF/PS/PVME system at
20
C.
Circles
show measured
cloud points. The modeling
was performed by means of
(
60
) and the binary
parameters are shown on the
edges
of the triangle. The
calculated spinodal area is
shaded
.
Open stars
composition of the coexisting
phases,
closed stars
critical
points [
74
]
THF
0.00
1.00
0.25
0.75
0.50
0.50
0.75
0.25
1.00
0.00
0.00
0.25
0.50
0.75
1.00
a
= −0.0125
n
= −0.6
z
= 0.0015
PS 6
PVME 87
THF
Fig. 35 Phase diagram of the
PS/PVME/THF system at
20
C.
Circles
measured cloud
points,
closed stars
calculated
critical points,
open stars
calculated tie lines. The
values of the specific ternary
interaction parameters (
61
)
are indicated on the
edges
; the
binary interaction parameters
are the same as in Fig.
34
[
74
]
0.00
1.00
0.25
0.75
0.50
0.50
0.75
0.25
1.00
0.00
0.00
0.25
0.50
0.75
1.00
PS 6
t
3
= - 0.02
PVME 87
parameters. Figure
35
shows the experimentally determined phase behavior of the
system THF/PS/PVME at 20
C, again along with the results of model calculations
on the basis of (
61
) and (
60
) by means of the ternary interaction parameters stated at
the edges of the triangle.
The agreement between the actually measured demixing behavior and that
modeled on the basis of binary interaction parameters plus composition-indepen-
dent ternary interaction parameters is surprisingly good. However, the results also
demonstrate how sensitive the calculated phase diagrams can be with respect to the
details of some interaction parameters. For instance, the analogous experiments
