Efficient Microwave-assisted Cationic Ring-opening Polymerization of Diverse Cyclic Imino Ethers - Unexpected Copolymerizaion Behaviour
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Lambermont-Thijs, Hanneke M. L.; Fijten, Martin W. M.; van der Linden, A. J.; van Lankvelt, Bart M.; Bloksma, Meta M.; Schubert, Ulrich S.; Hoogenboom, Richard
- Abstract:
- The recently developed fast microwave-assisted
cationic ring-opening polymerization procedure for 2-oxazolines
seems to be ideally suited for slower polymerizing cyclic
imino ether monomers. In this study we report the effect of the
cyclic imino ether structure on the polymerization rate under
exactly the same microwave-assisted conditions revealing that
indeed less reactive cyclic imino ethers, including 2-oxazines as
well as 4- and 5-substituted 2-oxazolines, can be polymerized to
at least 50% conversion for the slowest monomer, namely
5-methyl-2-butyl-2-oxazoline, within 10 h. In addition, the copolymerization behavior of 4-ethyl-2-butyl-2-oxazoline with
2-methyl-2-oxazoline and 2-phenyl-2-oxazoline unexpectedly revealed faster incorporation of the less reactive 4-ethyl-2-butyl-2-
oxazoline monomer compared to 2-phenyl-2-oxazoline due to the increased bulk of the latter monomer amplifying the sterical
hindrance for polymerization onto the 4-ethyl-2-butyl-2-oxazolinium propagating species.
- Year:
- 2011
- Type of Publication:
- Article
- Journal:
- Macromolecules
- Volume:
- 44
- Pages:
- 4320 - 4325