Dielectric properties of shrinkage-free poly(2-oxazoline) networks from renewable resources

Fabio Blaschke, Philipp Marx, Stefan Hirner, Inge Mühlbacher, Karin Wewerka, Frank Wiesbrock

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

In the course of this study, the dielectric and physicochemical properties of poly(2-oxazoline) (POx) networks from renewable resources were compared with those of fossil-based polyamide 12 (PA 12) networks. POx was synthesized by the energy-efficient, microwave-assisted copolymerization of 2-oxazoline monomers, which were derived from fatty acids of coconut and castor oil. For the preparation of composites, aluminum nitride nanoparticles n-AlN and microparticles μ-AlN as well as hexagonal boron nitride BN submicroparticles were used. Additionally, 0, 15, or 30 wt.% of a spiroorthoester (SOE) were added as an expanding monomer aiming to reduce the formation of shrinkage-related defects. For the crosslinking of the polymers and the SOE as well as the double ring-opening reaction of the SOE, a thermally triggered dual-cure system was developed. The fully-cured blends and composites containing SOEs exhibited lower densities than their fully-cured SOE-free analogues, which was indicative of a lower extent of shrinkage (or even volumetric expansion) during the curing reaction, which is referred to as relative expansion RE. The RE amounted to values in the range of 0.46 to 2.48 for PA 12-based samples and 1.39 to 7.50 vol.% for POx-based samples. At 40 Hz, the “green” POx networks show low loss factors, which are competitive to those of the fossil-based PA 12.
OriginalspracheEnglisch
Aufsatznummer1263
Seitenumfang15
FachzeitschriftPolymers
Jahrgang13.2l021
Ausgabenummer8
DOIs
PublikationsstatusVeröffentlicht - 13 Apr. 2021

Bibliographische Notiz

Funding Information:
Acknowledgments: The research work was performed within the K-Project PolyTherm at the Polymer Competence Center Leoben GmbH (PCCL, Austria) within the framework of the COMET-program of the Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology and the Federal Ministry for Digital and Economic Affairs with contributions by the Graz University of Technology and the Montanuniversitaet Leoben. Funding is provided by the Austrian Government and the State Government of Styria.

Funding Information:
Funding: This research was funded by the Austrian Government and the State Government of Styria; funding number FFG-862835.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

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