Design and characterisation of polymer-ceramic fibre interphase in hybrid materials for ultrasonic application (PolCerIntHyb)

• Forschungsstelle: COST
• Projektnummer: C14.0091
• Projekttitel Englisch: Design and characterisation of polymer-ceramic fibre interphase in hybrid materials for ultrasonic application (PolCerIntHyb)

Schlüsselwörter (Englisch)

Ferroelectric hybrids; KNL-NTS fibres; PZT fibres; ceramic-polymer interphase; piezoelectric charge constant; electromechanical coupling factor

Forschungsprogramme (Englisch)

COST-Action MP1202 - Rational design of hybrid organic-inorganic interfaces: the next step towards advanced functional materials

Kurzbeschreibung (Englisch)

The main goal of this project is the investigation of polymer coatings on ceramic fibres with modified surfaces and the investigation of the curing behaviour due to the modified surface and radial stresses. As a second goal the influence of the polymer coating on ferroelectric properties of the hybrid material for ultrasonic applications will be investigated. It is known that the electromechanical coupling factor of 1-3 composites is typically lower than the equivalent bulk material ones, but they can be improved by using an additional coating (i.e. interlayer). The electromechanical coupling factor can be increased by pre-coating the fibre with a soft interlayer. So-called 1-1-1-3 hybrids will be composed of a ferroelectric ceramic core, an interphase layer (e.g. fatty acids, amides, waxes or oils), a polymeric shell (interlayer) and a polymeric matrix. The interphase layer and the interlayer will allow the free movement of the ferroelectric fibres because the blocking or clamping by the inactive polymeric matrix will be avoided resulting in a higher electromechanical coupling factor. Ferroelectric characterisation will be performed on single fibres and their hybrids, while the interphase will be investigated by spectroscopy methods, such as FTIR and Raman, Electron Spin Resonance or solid-state NMR. Collaborations with other COST members will be beneficial for the comprehension of the aforementioned polymer-ceramic interactions.

Weitere Hinweise und Angaben (Englisch)

Full name of research-institution/enterprise: Eidg. Materialprüfungs- und Forschungsanstalt EMPA Hochleistungskeramik

Partner und Internationale Organisationen (Englisch)

AT; BE; BG; HR; CZ; FI; FR; DE; EL; IE; IL; IT; LT; NL; NO; PL; PT; RO; RS; SI; ES; SE; TR; UK

Abstract (Englisch)

The main goal of this project is the investigation of polymer coatings on ceramic fibres with modified surfaces and the investigation of the curing behaviour due to the modified surface and radial stresses. As a seconä goal the influence of the polymer coating on ferroelectric properties of the hybnd material for ultrasonic applicaions will be investigated. lt is known that the electromechanical coupling factor of 1-3 composites is typically lower than the equivalent bulk material ones, but they can be improved by using an additional coating ( ie. interlayer). The electromechanical coupting factor can be increased by pre-coating the fibre with a soft interlayet. So-called 1-1-1-3 hybrids will be composed of a ferroelectric ceramic core, an interphase layer fe.g. fatty acids amides, waxes or oils), a polymene shell (intedayer) and a polymenc matrix. The interphase layer and the interlayer will allow the free movement of the ferroelectnc fibres because the blocking or clamping by the inactive polymeric matrix will be avoided resulting in a higher electromechanical coupling factor. Fermelectric characterisation will be performed on single fibres and their hybnds, while the interphase will be investigated by spectroscopic j methods. In this pmject, ferroelectnc fibres, namely PZT and KNL-NTS have been successfutly produced by thermoplastic processing and thermally treatmented. The fibres were analysed by SEM, XRD and electromechanical measurements. The knowledge on KNL-NTS fibres is limited and therefore a deeper study on the thermal treatment had to be done. Nano-Powder was synthesized by Spanish partner CSIC and processed at Empa. The resuits showed that the volume fraction for T, and 0 phases depends on sintering time. The d33 and dielectric constant decreased with sintering time. The best results were achieved with 2 hours dwell time at 11 25C. The coercive electrical field decreases by increase of sintering time. The phase composition fTIO ratio) and the grain size strongly influence the electromechanical results of the fibres. These results have been submitted to the Journal of European Ceramic Society in January 2016. In addition coating based on polyurethane and epoxy was investigated. Single fibre dip coating experiments were used to instigate coating behaviour of these two systems. Dip coating experiments where successful and a coating thickness between 10 and 90 micrometre could be achieved with both coating systems. However reproducibility was very poor, especially for the epoxy resin systems. The main problem for the epoxy resin was the increase in viscosity during the processing time (pot time). Because of this a deeper study on different commercial available epoxy resins as a coating system was investigated. Finally we found one System which shows very good reproducibility and almost no change of viscosity during the processing time. Additionally a dip coaung device for the later project phases was designed and manufactured.

Datenbankreferenzen (Englisch)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C14.0091