Copoly(2-nonyl-2-oxazoline)-stat-poly(2-dec-9′enyl-2-oxazoline)s can be crosslinked by the thiol-ene reaction with glycol dimercaptoacetate. The copoly(2-oxazoline)-stat-copolyester is tested as dielectric for high-voltage applications, either as unfilled resin or as composite with nanoscaled fillers of silica, alumina, and hexagonal boron nitride. During AC voltage tests, all materials have an average breakdown strength of 45–50 kV mm⁻¹. For DC voltage tests, samples with SiO₂ (hBN) have an average breakdown strength of ≈100 (80) kV mm⁻¹, while the unfilled copoly(2-oxazoline) has an average breakdown strength of ≈60 kV mm⁻¹. Permittivity measurements at 20 °C and 50 Hz reveal that all nanocomposites are dielectrics (D = 0.06–0.08), while the unfilled copoly(2-oxazoline)s has a high loss factor of D = 8.43. This phenomenon can be retraced to the phase separation in the crosslinked copolymer, the M-OH functionality of silica and alumina particles, and models of polymer–particle interactions such as the Tanaka model, revealing that the nanofillers reduce the interfacial and dipolar polarizability. ... Read more

Radical induced cationic frontal polymerization (RICFP) is an extremely powerful and elegant alternative curing technique that allows cationic bulk curing of epoxy resins with very little energy consumption, as well as curing in compart-
ments that are not readily accessible. We recently introduced a bisphenol-A diglycidylether (BADGE) based system that allows the bubble-free photocuring of this widely used epoxy resin. In this article, we describe the high storage stability and possibili-ties to influence the curing speed via the initiator concentra-
tions of different formulations. These properties allow the adjustment of the frontal polymerization to ones need. We also show that the (thermo)mechanical and electrical properties of frontal cured epoxy polymers compares favorably with those of state of the art material. Finally, different strategies to over-
come the challenges on producing epoxy resin based mica
composites via RICFP are presented.
... Read more