TY  - JOUR
A1  - Baron, Philipp
A1  - Lenz, Philipp
A1  - Koch, Klaus P.
A1  - Wittmann, Armin
A1  - Fischer, Georg
T1  - Dielectric properties of unidirectional and biaxial flax/epoxy composites at frequencies up to 1 GHz
T2  - Materials Today Communications
N2  - The relative permittivity of flax/epoxy composites in unidirectional and biaxial orientations was mapped in the frequency range of 1 kHz to 200 kHz, and for the first time in the range of 1 MHz to 1 GHz. In addition, permittivity was investigated for the first time in the temperature range between − 20 °C and 50 °C. These composites, produced using the vacuum infusion process, are increasingly used for sustainable and lightweight structural components in the automotive industry. The relative permittivity was determined using a self-developed plate capacitor with an LCR bridge and an impedance analyzer. An examination of the microstructure of the flax/epoxy composites shows that the fibers are disordered in the composite, resulting in local variations in fiber volume fraction. Furthermore, it was shown that the matrix also infiltrates into the fiber itself, resulting in an increase of the matrix fraction. It was found that unidirectional fabrics had a higher relative permittivity than biaxial fabrics, due to a higher fiber volume fraction and lower proportion of epoxy. The results suggest that it is the fiber volume fraction, rather than the manufacturing process and fiber orientation, that primarily determines the relative permittivity. It was also found that the permittivity continues to decrease below room temperature and thus behaves in a manner typical of the material in this temperature range as well.
KW  - Verbundwerkstoff
KW  - Dielektrizitätszahl
KW  - Faserorientierung
KW  - Flachs
KW  - Epoxide
KW  - Dielectric analysis
KW  - Relative permittivity
KW  - Flax/epoxy composites
KW  - Unidirectional fiber orientation
KW  - Biaxial fiber orientation
KW  - Microstructure flax/epoxy
Y1  - 2023
UR  - https://hst.opus.hbz-nrw.de/frontdoor/index/index/docId/983
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:tr5-9832
VL  - 36
PB  - Elsevier
ER  -