Synthesis, Microwave-Assisted Polymerization, and Polymer Properties of Fluorinated 2-Phenyl-2-oxazolines: A Systematic Study
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Lobert, Matthias; Thijs, Hanneke M. L.; Erdmenger, Tina; Eckardt, Rebecca; Ulbricht, Christoph; Hoogenboom, Richard; Schubert, Ulrich S.
- Abstract:
- We present a detailed systematic
study of the synthesis and ability
of fluorinated 2-phenyl-2-oxazolines
to undergo polymerization. The synthesis
of these compounds is based on a
two-step procedure that gives the desired
2-oxazolines in moderate-to-good
yields. All the compounds were fully
characterized by IR and NMR (1H, 13C,
and 19F) spectroscopy, mass spectrometry,
and elemental analysis. The 2-oxazolines
were subsequently used as
monomers for living cationic ringopening
polymerization (CROP) with
microwave irradiation as the heat
source (T=140 8C), nitromethane as
the solvent, and methyl tosylate as the
initiator. The linear first-order kinetic
plots of the polymerizations accompanied
by a linear increase of the molecular
weight with conversion and low
polydispersity index (PDI) values (generally
below 1.30) indicate a living
polymerization mechanism. The resulting
polymerization rates reflect a
strong sensitivity to the quantity of fluorine
substituents in general and the
presence or absence of ortho-fluoro
substituents of the phenyl ring in particular.
All the polymers were isolated
and characterized by size-exclusion
chromatography and MALDI-TOF
mass spectrometry. Finally, a detailed
investigation of selected polymer properties
was performed by using differential
scanning calorimetry, thermogravimetric
analysis, and contact-angle
measurements, thus resulting in structure–
property relationships. Whereas
the thermal properties of the polymers
are mostly influenced by the presence
of ortho-fluoro substituents, the surface
properties are mainly determined by
the presence of para- and/or metafluoro
substituents.
- Year:
- 2008
- Type of Publication:
- Article
- Keywords:
- fluorine; oxazolines; polymerization; surface energy; thermal properties
- Journal:
- Chemistry - A European Journal
- Volume:
- 14
- Pages:
- 10396 - 10407