Chemistry Reference
In-Depth Information
Two polyfluoroacrylates are manufactured on a small commercial scale for some special uses in jet
engines. These are poly(1,1-dihyroperfluorobutyl acrylate):
F
n
F
O
O
CF
3
F
F
and poly(3-perfluoromethoxy-1,1-dihydroperfluoropropyl acrylate):
F
n
F
CF
3
O
O
O
F
F
The polymers are prepared by emulsion polymerization with persulfate initiators.
Although many other fluorine containing polymers were described in the literature, it is not
possible to describe all of them here. They are not utilized commercially on a large scale. A few,
however, will be mentioned as examples. One of them is polyfluoroprene [
288
]:
F
n
o
m
F
F
The polymer is formed by free-radical mechanism, in an emulsion polymerization using redox
initiation. All three possible placements of the monomer occur [
267
].
Polyfluorostyrenes are described in many publications. A
-fluorostyrene can be formed by
cationic mechanism [
289
]. The material softens at 240-260
C. An
b
-trifluorostyrene can be
polymerized by free-radical mechanism to yield an amorphous polymer that softens at 240
C[
290
].
Ring-substituted styrenes apparently polymerize similarly to styrene. Isotactic poly(
a
,
b
,
b
-fluorostyrene)
melts at 265
C. It forms by polymerization with Ziegler-Natta catalysts [
291
]. The
o
meta
analog,
however, polymerized under the same conditions yields an amorphous material [
291
].
6.17.7 Poly(vinyl chloride)
Poly(vinyl chloride) is used in industry on a very large scale in many applications, such as rigid
plastics, plastisols, and surface coatings. The monomer, vinyl chloride, can be prepared from
acetylene:
Cl
+
HCl
