Kinetic Investigations on Microwave-Assisted Statistical Terpolymerizations of 2-Oxazoline Monomers

Abstract

The microwave-assisted statistical terpolymerization of 2-oxazolines via a living cationic ring-opening polymerization mechanism is discussed. Kinetic investigations on the terpolymerizations of combinations of 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-nonyl-2-oxazoline, and 2-phenyl-2-oxazoline were performed by heating separate polymerization mixtures for different predefined times. The resulting polymer solutions were analyzed by gas chromatography and size exclusion chromatography, demonstrating the living character of the statistical terpolymerizations. In addition, the monomer distribution throughout the polymer chains is discussed based on the linear first order kinetic plots of the separate monomers in the terpolymerizations. The observed differences in monomer distribution are expected to influence the polymer properties, which will be the focus of future investigations.

Poly(2‐oxazoline)s based on fatty acids

“…Accordingly the surface energy of the copolymers remains below 25 mN/m up to the incorporation of 60 wt% PhOx. Further spontaneous control over the microstructure of the NonOx containing copolymers could be obtained by statistical terpolymerizations resulting, e.g., in ''gradient-random'', ''gradient-block'', or ''random-block'' copolymers [45]. The previously discussed studies reported the bulk properties of NonOx containing copoly(2-oxazoline)s demonstrating the beneficial semi-crystalline behavior of this fatty acid derived poly(NonOx).…”

Accelerated living cationic ring-opening polymerization of a methyl ester functionalized 2-oxazoline monomer

“…Herein, MestOx was copolymerized with MeOx or EtOx, both with a monomer to monomer ratio (M 1 : M 2 ) of 50 : 50 using the same conditions as for the homopolymerisations. Commonly the copolymerisation of different 2-oxazoline monomers follows the same relative order of monomer incorporation as the corresponding homopolymerisations of the individual monomers; [28][29][30][31] the only reported exception being the copolymerisation of 2-butyl-4-ethyl-2-oxazoline with 2-phenyl-2-oxazoline ascribed to steric constraints. 32 Remarkably, the first order kinetic plots for the copolymerisation of MestOx with MeOx or EtOx also revealed that MeOx or EtOx is incorporated faster than the MestOx, which is the reversed order compared to the homopolymerisations (Fig.…”

One Decade of Microwave‐Assisted Polymerizations: Quo vadis?

“…[152] From one-pot syntheses, also statistical and gradient copoly(2-oxazoline)s as well as quasi (di-)block copoly(2-oxazoline)s were prepared by Schubert and coworkers under microwave irradiation. [150,155,156] Scheme 13. Schematic representation of the chain-transfer reactions and subsequent chain-coupling by-reactions during the polymerization of 2-oxazolines, shown on the example of the synthesis of the second block of a poly(2-nonyl-2-oxazoline)-block-poly-(2-ethyl-2-oxazoline) diblock copolymer.…”