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Table 5 Influence of monomer feed composition on copolymerization of allylethers
with DEF in solvent-free conditions (C
PI
=
5 wt-% of Darocur 1173; Irradiation:
l
=
365 nm;
P
=
8mW cm
2
).
Initial rate
Conversion
(R
p
)
0
(mmol
kg
1
s
1
)
(R
p
)
0
(mmol
kg
1
s
1
)
Donor
monomer
f
D
a
p
A
N
(%)
p
D
N
(%)
HBVE
0.50
76.4
76.4
100
100
AHE
0.25
4.1
0.9
100
78
AHE
0.33
3.7
1.0
100
64
AHE
0.50
3.5
1.3
100
49
AHE
0.66
3.3
0.8
100
38
AIG
0.25
3.9
0.9
100
62
AIG
0.33
3.1
0.8
100
58
AIG
0.50
5.8
0.9
100
40
AR
0.25
8.9
2.5
100
100
AR
0.50
9.7
4.1
100
100
AIR
0.33
2.4
1.2
100
83
AIR
0.50
4.0
3.7
84
93
a
Molar ratio of donor monomer in feed composition: f
D
=
[D]
0
/([A]
0
รพ
[D]
0
).
limiting conversion (Table 5). Allyl riboside appears in the series of
allyloxy derivatives under study as the more convenient monomer from
the viewpoint of the initial reactivity and of final conversion.
4.4 Networks : Polymerization of sugar-based multifunctional allyloxy
monomers
Thanks to their high polymerizability, low-shrinkage level, low-toxicity
and low volatility, telechelic vinylether-based resins appear to be an at-
tractive alternative to acrylate UV-cured systems suitable for various ap-
plications, and in particular as protective coatings. Moreover, a broad
range of vinylether compounds are now commercially available. Indeed,
in the past few years, thermal and photo-induced cationic crosslinking
polymerization of simple commercial divinylethers have been thoroughly
studied in term of kinetics and also from the viewpoint of materials
properties.
72
The possibility of forming original networks by free-radical polymer-
ization of multifunctional allyloxy monomers derived from carbohydrates
prompted us to study new model monomers designed with that purpose,
namely, hybrid monomers containing both one donor and one acceptor
unsaturation and a tetra-allyl derivative to be copolymerized with DEM or
DEF (Scheme 10).
69
4.4.1
Polymerization kinetics
Hybrid donor-acceptor monomers. The hybrid allyloxy monomers MAIR
and FAIR were photopolymerized as thin liquid films under conditions
similar to those for the simple vinyloxy or allyloxy monomers discussed
in the preceding sections. Using FTIR spectroscopy, the disappearance of
reactive unsaturations upon 365 nm photo-irradiation was followed at
775 cm
1
, 810 cm
1
and 930 cm
1
respectively for fumarate, maleate and
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