Chemistry Reference
In-Depth Information
(1) Elimination of an alkoxy radical :
O
P
n
O
P
n
P
n
R
+
OR
R
+
(2) Transfer reaction by H-abstraction by the propagating free-radical :
O
O
O
P
n
R
+
P
n
H
+
R
R
H
(3) Possible dissociation of allyl radical :
O
O
+
R
R
acrolein
(4) Disproportionation :
O
O
P
n
+
R
+
P
n
'
H
P
n
P
n
R
H
Scheme 6 Possible reactions competing with the propagation allylether-based free
radicals.
each comonomer. The authors claimed the reactivity ratios to be equal to
zero for both types of unsaturated donor monomers, concluding that
copolymerization of allyloxy compounds proceeds as an unperturbed
alternating copolymerization, a feature generally observed for the co-
polymerization of vinylethers.
41
A study reporting on the reactivity of allyloxy groups attached to various
molecular moieties in the free-radical copolymerization with styrene has
raised our attention on the importance of the functionality and particu-
larly of the presence of intramolecular hydrogen bonding on the poly-
merizability. Indeed, neither copolymerization nor chain transfer
through hydrogen abstraction occurs in some cases, unlike what is ob-
served with more conventional low polarity monomers.
42
Moreover, the
importance of dipolar effects and H-bonding on the polymerization
kinetics have already been established for the free-radical photo-
polymerization of acrylate and methacrylate monomers.
43,44
Thermal and UV-initiated cyclo-polymerizations of mixed allyl-
butenedioate monomers with both donor and acceptor unsaturations
such as methyl allyl fumarate or maleate were recently described.
45
Hyperbranched macromolecules were obtained by free radical alter-
nating copolymerization of bifunctional monomers containing two
polymerizable double bonds of allyl and vinylene type with styrene or
maleic anhydride. Thanks to their original structure, this new class of
liquid blends exhibit improved mechanical and physical properties
useful for a wide range of coating applications.
46
The free-radical copolymerization of electron-donor olefinic mono-
mers, including commercial allyl and vinyl ethers, was quite frequently
reported and studied during last years and seems to present interesting
potentialities for the synthesis of new bio-sourced polymers. However the
only publication devoted to donor-acceptor copolymerization of mono-
mers from biomass was focused on the photopolymerization of divi-
nylfumarate, a bifunctional monomer bearing both type of double
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