Chemistry Reference
In-Depth Information
H
+
+
O
H
O
H
O
+
+
H
O
O
+
O
O
Scheme 9 Possible transfer reactions and rearrangements of allyl ethers.
Table 4 Molar compositions of the vinyl and allylic copolymers copolymerized in
solvent-free conditions. (equimolar amount of comonomers in blends; C
PI
=
5 wt-% of
Darocur 1173; Irradiation:
l
=
365 nm; P
=
8mW cm
2
).
HSQC NMR
FTIR
Peak
intensity (I
i
)
Molar
fraction (f
i
)
Conversion
p
i
N
(%)
Molar
fraction (f
i
)
Copolymers
Monomers
DEF-AHE
DEF
1
0.68
100
0.67
AHE
0.2392
0.32
49
0.33
DEF-AIG
DEF
1
0.64
100
0.71
AIG
0.2817
0.36
40
0.29
DEF-HVE
DEF
1
0.52
100
0.50
HVE
0.4661
0.48
100
0.50
DEF-VIG
DEF
1
0.48
100
0.50
VIG
0.5413
0.52
100
0.50
i: donor or acceptor monomer.
less abundant than the chains started and stopped by a transfer reaction
(about 55 mol-%).
T
he higher MWs of copolymers obtained from vinylether (Table 2:
M
n
W12000 g
mol
1
) did not allow their detailed analysis by ESI-MS.
However, thanks to HSQC NMR analysis, molar fractions of electron-donor
monomer were determined and compared to values obtained by FTIR
(Table 4). For copolymers synthesized from vinyloxy compounds (DEF-VIG
and DEF-HVE), the molar fraction of donor monomer was equal to 0.5 as
expected for a perfectly alternating copolymerization, hence contrasting
with allylether copolymers (DEF-AHE and DEF-AIG), for which the molar
fraction in donor monomer was close to 0.3, confirming the easier in-
sertion of the fumarate comonomer during propagation.
It is possible to adjust the relative proportions of donor and acceptor
monomers to ensure a high level of fractional conversion for the less
reacting allylic function. Decreasing the proportion of donor monomer
AHE or AIG in the blends with DEF was shown to increase noticeably the
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