Chemistry Reference
In-Depth Information
0.040
(a)
p=0.95. Xn=20
0.032
0.024
i
0.016
p=0.98. Xn=50
p=0.99. Xn=100
0.003
0
0
50
100
150
200
250
i
0.040
(b)
p=0.90, Xw=19
0.032
0.024
i
0.016
p=0.95, Xw=39
p=0.98, Xw
=9
9
p=0.99, Xw=199
0.003
0
0
50
100
150
200
250
i
FIGURE 7.5
(a) Mole fraction distribution of reaction mixture in linear step-growth polymerization for
several extents of reaction. (b) Weight fraction distribution of reaction mixture in linear
step-growth polymerization for several extents of reaction
[2]
.
N
N
p
0
x
i
5
x
i
2
x
1
5
1
2
ð
1
p
Þ
p
(7-30)
2
5
i
5
2
i
5
1
Since we know the distribution functions, we can calculate average molecular
weights. To accomplish this, use must be made of the following series summations:
N
1
ya
y
2
1
(7-31a)
5
2
ð
1
2
a
Þ
y
5
1
N
1
1
a
y
2
a
y
2
1
(7-31b)
5
3
ð
1
a
Þ
2
y
5
1
