Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable Resources
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-oxazol...
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| Format: | Article |
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MDPI AG
2021-04-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/13/8/1263 |
| _version_ | 1797537775364341760 |
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| author | Fabio Blaschke Philipp Marx Stefan Hirner Inge Mühlbacher Karin Wewerka Frank Wiesbrock |
| author_facet | Fabio Blaschke Philipp Marx Stefan Hirner Inge Mühlbacher Karin Wewerka Frank Wiesbrock |
| author_sort | Fabio Blaschke |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T12:21:01Z |
| format | Article |
| id | doaj.art-3fac1b840ba5482182e96535e98e06f4 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-10T12:21:01Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-3fac1b840ba5482182e96535e98e06f42023-11-21T15:26:00ZengMDPI AGPolymers2073-43602021-04-01138126310.3390/polym13081263Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable ResourcesFabio Blaschke0Philipp Marx1Stefan Hirner2Inge Mühlbacher3Karin Wewerka4Frank Wiesbrock5Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, AustriaPolymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, AustriaPolymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, AustriaPolymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, AustriaCenter for Electron Microscopy, Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, AustriaPolymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, AustriaIn 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.https://www.mdpi.com/2073-4360/13/8/1263nanodielectricsvolumetric expansionrenewable resourcespoly(2-oxazoline)polyamide 12dual-cure mechanism |
| spellingShingle | Fabio Blaschke Philipp Marx Stefan Hirner Inge Mühlbacher Karin Wewerka Frank Wiesbrock Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable Resources Polymers nanodielectrics volumetric expansion renewable resources poly(2-oxazoline) polyamide 12 dual-cure mechanism |
| title | Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable Resources |
| title_full | Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable Resources |
| title_fullStr | Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable Resources |
| title_full_unstemmed | Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable Resources |
| title_short | Dielectric Properties of Shrinkage-Free Poly(2-Oxazoline) Networks from Renewable Resources |
| title_sort | dielectric properties of shrinkage free poly 2 oxazoline networks from renewable resources |
| topic | nanodielectrics volumetric expansion renewable resources poly(2-oxazoline) polyamide 12 dual-cure mechanism |
| url | https://www.mdpi.com/2073-4360/13/8/1263 |
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