Chemistry Reference
In-Depth Information
Substituting
2
4
0
@
1
A
0
@
1
A
0
@
1
A
0
@
1
A
M
A
1
M
A
e
e
1
f
a
a
1
b
f
e
1
f
c
c
1
d
ð
M
n
Þ
blend
5
0
@
1
A
0
@
1
A
0
@
1
A
0
@
1
A
M
B
1
M
B
2
1
e
e
1
f
b
a
1
b
f
e
1
f
d
c
1
d
1
2
0
1
0
1
M
A
1
w
2
M
A
a
a
1
b
c
c
1
d
4
@
A
@
A
5
w
1
0
@
1
A
0
@
1
A
M
B
1
w
2
M
B
2
1
b
a
1
b
d
c
1
d
1
w
1
2
0
2
3
2
3
1
2
1
2
1
M
A
ð
a
1
b
Þ
a
M
B
ð
a
1
b
Þ
b
4
@
4
5
4
5
A
5
w
1
1
0
@
2
4
3
5
2
4
3
5
1
A
2
1
2
1
2
1
M
A
ð
c
1
d
Þ
c
M
B
ð
c
1
d
Þ
d
1
w
2
1
(2A-5)
2
1
w
1
ð
M
n
Þ
1
1
w
2
ð
M
n
Þ
2
ð
M
n
Þ
blend
5
(2A-6)
This is equivalent to
Eq. (2-11)
with
ð
M
n
Þ
I
substituted for M
i
.
Similar expressions can be developed in a straightforward manner for M
w
;
M
z
and so on.
PROBLEMS
2-1
If e
qua
l weights of polymer A and polymer B are mixed, calculate M
w
and M
n
of the mixture:
Polymer A: M
n
5
;
;
M
w
5
;
35
000
90
000
Polymer B: M
n
5
150
;
000
;
M
w
5
300
;
000
2-2 Calcium stearate (Ca(OOC(CH
2
)
16
CH
3
)
2
) is sometimes used as a lubricant
in the processing of poly(vinyl chloride). A sample
of
PVC compound
co
nta
ining 2 wt% calcium stearate was found to have M
n
5
25000
:
What
is M
n
of the balance of the PVC compound?
2-3
If equal weights of “monodisperse”
p
olymers with molecular weights of
5000 and 50,000 are mixed, what is M
z
of the mixture?
