Chemistry Reference
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a
1,0
0,8
0,6
0,4
0,2
0,0
0
100
200
300
400
500
600
700
800
r
b
1,0
0,8
0,6
0,4
0,2
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
y
Fig. 24 Simulation results of the Baker Williams column for a copolymer having a distribution
according to (
16
) with respect to the molecular weight (a) and the chemical composition (b), where
the
symbols
show the fractionation data and the
lines
represent the original distribution
(
16
) have a broader distribution with respect to the chemical heterogeneity, but the
same broadness related to the molecular weight. In Fig.
24
, the integral distribution
functions constructed from the fractionation data for a copolymer with this distri-
bution function is plotted. From the integral distribution function
I
(
r
, 0.5), it can be
seen that five fractions are not sufficient to yield the correct original function.
Deviation can be found at higher molecular weights (Fig.
24a
). The distribution
I
(100,
y
) obtained from the fractionation data is also too narrow in comparison with
the original distribution (Fig.
24b
), where deviations occur at high and at low values
of the chemical composition. This result reflects the complex superposition of both
kinds of polydispersity.
R
ยจ
tzsch et al. [
50
] found by the simulation of the fractionation of homopolymers
in the BW column a practical linear relationship between the number of maximal
