Chemistry Reference
In-Depth Information
HNO
3
NO
2
NH
HNO
2
Fe
N
2
Cl
The radical sites are capable of initiating polymerizations of monomers. A similar approach can be
taken with cellulose [
334
]. Mercerized cotton and sodium salt of carboxymethyl cellulose will react
with
p
-aminophenacyl chloride:
OH
OH
O
HO
HO
+
O
O
O
NH
2
O
Cl
n
n
O
O
O
Na
NH
2
The material can be converted to diazonium salts and then decomposed with ferrous ions in the
presence of some vinyl monomers to form graft copolymers. Acrylonitrile forms graft copolymer
readily without formation of any homopolymers. Styrene and vinyl acetate, however, do not.
A modification of this technique is to conduct the diazotization reaction in the presence of emulsifiers
[
335
]. The amounts of graft copolymers that form with acrylic and methacrylic monomers and
N
-vinylpyrrolidone depend upon the nature and pH of the emulsifiers, the reaction time, and the
temperature.
Ceric ions form graft copolymers with various macromolecules by a redox mechanism. The
reactions can be illustrated as follows:
R H
+
R
OH
Ce
Ceric complex
R H
(or
R
O
+
Ce
)
H
+
The almost exclusive formation of free radicals on the polymeric backbones results in formations
of many products that are close to being free from homopolymers [
346
,
350
]. The reactions are
