Does the oxa-Michael reaction of 2-trifluoromethacrylic acid lead to fluorinated polyesters?
2-Trifluoromethacrylic acid (MAF) is a peculiar fluorinated functional monomer. Though it is known to polymerise via C&z.dbd;C bond cleavage under anionic initiation, its oxa-Michael addition polymerisation afforded polyesters bearing trifluoromethyl side groups. This oxa-Michael addition was at...
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Published in | Polymer chemistry Vol. 12; no. 31; pp. 458 - 4523 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
21.08.2021
|
Subjects | |
Online Access | Get full text |
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Summary: | 2-Trifluoromethacrylic acid (MAF) is a peculiar fluorinated functional monomer. Though it is known to polymerise
via
C&z.dbd;C bond cleavage under anionic initiation, its oxa-Michael addition polymerisation afforded polyesters bearing trifluoromethyl side groups. This oxa-Michael addition was attempted in the presence of radical (peroxides), basic (amines and phosphines) and acidic (AlCl
3
, triflic acid, and
p
-toluenesulfonic acid) reactants and catalysts which led to the formation of oligomers with various yields (up to 57%) and molar masses (up to 2200 g mol
−1
). The obtained polyesters were characterised by GC/MS, IR,
19
F NMR,
1
H NMR and
13
C NMR spectroscopy techniques and MALDI-TOF, and their thermal properties were determined by thermogravimetric analysis and differential scanning calorimetry. Triphenylphosphine and piperidine led to the highest degree of polymerization DP
n
(up to the 16th adduct) with a degradation temperature of about 200 °C. The glass transition temperatures (
T
g
) were −59 and −46 °C for the MAF bisadduct (diMAF) and oligoMAF, respectively. Such oligomers were hydrophobic, evidenced by a water contact angle measurement of 107°, showing that the contribution of the trifluoromethyl group was higher than that of the ester function.
2-Trifluoromethacrylic acid (MAF) is a peculiar fluorinated functional monomer. |
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Bibliography: | 10.1039/d1py00685a Electronic supplementary information (ESI) available. See DOI |
ISSN: | 1759-9954 1759-9962 |
DOI: | 10.1039/d1py00685a |