Silicone-based dielectric elastomers have been recognized as a promising material group as electroactive polymer (EAP). Compare to other EAP materials, silicone-based dielectric elastomers exhibit large deformability, excellent dielectric properties, high energy density, low weight and low cost, which are indicative of great potentials for the applications as actuators, generators and sensors. However, because of the concerns for the long-term reliability, only few industrial applications of dielectric elastomers are established up to now. Therefore, the purposes of this work are to give a systematic investigation of the long-term electromechanical ageing of dielectric elastomer and to clarify the correlations between changes in material properties. The experimental work of this thesis consists of two parts, the pre-tests and the main-tests. The pre-tests aim to find a suitable electrode for the long-term electromechanical ageing investigation. The main-tests aim to investigate the electromechanical fatigue behavior of silicone-based dielectric elastomers, and to interpret the correlations between electromechanical ageing process and the changes of material properties. The results of this work showed that the permittivity declined with an increasing loading cycles. Along with this, the cross-linking density was increased after electromechanical ageing. This changes were especially significant in the elastomers with more excessive functional groups. A decreasing permittivity together with an increasing cross-linking density led to an increasing breakdown strength, which was verified by the breakdown strength measurements. For the reliability analysis, an increasing breakdown strength might help extend the lifetime of DEA. However, due to the decreasing permittivity and an increasing cross-linking density in the electromechanical ageing process, the strain and stress that DEA can generate, will become lower and lower. This work represent contributions to the characterization and analysis of the electromechanical ageing behaviors of dielectric elastomers. On the basis of these findings, a suitable chemical formulation can be optimized for the design and optimization of dielectric elastomers. Results of this work also provide important information for the further long-term investigation on the electromechanical ageing of dielectric elastomers, which is ssential for the industrialization of actuator applications.

EMK-spezifische Daten:

Lagerort Dokument: Archiv Institut EMK. Anfrage über Sekretariate

Bibliotheks-Siegel: 17/24 EMKM 1904 Art der Arbeit: Masterarbeit

Beginn Datum: 01-04-2015

Ende Datum: 30-09-2015