Chemistry Reference
In-Depth Information
control of such systems is frequently on monomer concentration in the gas
phase over the reaction mixture. This is because gas phase concentrations
vary less with temperature, pressure, and solvent. What monomer composi-
tion in the gas phase is needed to produce a copolymer containing 30 mol
% propylene. The reactivity ratio of ethylene (
r
1
) has been found to be 5,
based on gas phase concentrations.
9-10
In the copolymerization of vinyl chloride and vinyl acetate, what monomer
feed composition is needed to produce a copolymer containing 5 mol%
vinyl acetate? (The reactivity ratios are listed in
Table 9.1
.)
9-11
Copolymers of methyl methacrylate and styrene (and other monomers) are
made with acrylamide or methacrylamide and then post-reacted with form-
aldehyde and alcohols to yield the
N
-alkoxymethyl derivative of the acryl-
amide unit:
The product can be cross-linked with hydroxyl-containing polymers:
-
Polymer
C
4
H
9
OH
Polymer
Polymer
OH
+ 2 CH
2
O
low
temp.
C
NH
2
O
C
NH
2
O
C
NH
O
C
NH
O
C
NH
O
C
HN
O
+
H
9-11-1
CH
2
OH
CH
2
OH
CH
2
CH
2
O
O
C
4
H
9
C
4
H
9
POLYMER
POLYMER
POLYMER
C
O
CO
HO
C
O
CO
HN
N
+
HN
NH
+ C
4
H
9
OH
9-11-2
CH
2
CH
2
CH
2
CH
2
O
O
O
O
C
4
H
9
C
4
H
9
C
4
H
9
POLYMER
Such materials are used in baking finishes. Assume that a manufacturer
wishes to make a polymer based on methyl methacrylate or styrene and
about 15 mol% acrylamide. If the following reactivity ratios are correct, is
there any advantage in terms of evenly spaced cross-links in using either
styrene or methyl methacrylate as the major component?
