Chemistry Reference
In-Depth Information
2-hydroxyethyl methacrylate, glycidyl methacrylate, and
n
-butyl methacrylate Three different
solvents,
-dimethylformamide were used. They found that all three
solvents effected the composition of styrene-2-hydroxyethyl methacrylate copolymer. Liang and
Hutchinson [
147
] also observed variations in monomer reactivity ratios with solvent polarity. Butanol
was the only one that affected styrene butyl methacrylate copolymer composition. None of the
solvents appeared to effect the composition of the styrene-glycidyl methacrylate copolymer.
n
-butanol, toluene, and
N
,
N
3.7 Terpolymerization
A quantitative treatment of terpolymerization, where three different monomers are interpolymerized,
becomes complex. Nine growth reactions take place [
155
]:
Reaction
Rate
R
11
¼ k
11
½
M
1
½
M
1
K
11
M
1
þ
M
1
!
M
1
M
1
R
12
¼ k
12
½
M
1
½
M
2
k
12
M
1
þ
M
2
!
M
1
M
2
R
13
¼ k
13
½
M
1
½
M
3
k
13
M
1
þ
M
3
!
M
1
M
3
R
21
¼ k
21
½
M
2
½
M
1
k
22
M
2
þ
M
1
!
M
2
M
1
R
22
¼ k
22
½
M
2
½
M
2
k
22
M
2
þ
M
2
!
M
2
M
2
R
23
¼ k
23
½
M
2
½
M
3
k
23
M
2
þ
M
3
!
M
2
M
3
R
31
¼ k
31
½
M
3
M
½
k
31
M
3
þ
M
1
!
M
3
M
1
R
32
¼ k
32
½
M
3
½
M
2
k
32
M
3
þ
M
2
!
M
3
M
2
R
¼ k
½
M
3
½
M
3
k
33
33
33
M
3
þ
M
3
!
M
3
M
3
There are six reactivity ratios in copolymerizations of three monomers [
148
]:
r
12
¼ k
11
=k
12
r
13
¼ k
11
=k
13
r
21
¼ k
22
=k
21
r
23
¼ k
22
=k
23
r
31
¼ k
33
=k
31
r
32
¼ k
33
=k
32
The rates of disappearance of the three monomers are given by
d
½
M
1
=
d
t ¼ R
11
þR
21
þR
31
d
½
M
2
/d
t ¼ R
12
þ R
22
þ R
32
d[M
3
=
d
t ¼ R
13
þR
23
þR
33
By assuming steady state conditions for the three radicals, M
1
, M
2
, and M
3
it is possible to write:
R
12
þR
13
¼ R
21
þR
31
;
R
21
þR
23
¼ R
12
þR
32
;
R
31
þR
32
¼ R
13
þR
23
An equation for terpolymer composition was developed from the rate expressions by expressing
the steady state with the relationships [
94
]:
R
12
¼ R
21
;
R
23
¼ R
32
;
R
31
¼ R
13
:
