Study On Preparation And Properties In Silicone Matrix Electroactive Dielectric Elastomer Composites

Electroactive polymers (EAPs) are new electro-sensitive materials, behaving as actuators, changing their shape in response to electrical stimulation directly, possessing high energy density, high efficiency and fast response speed. Actuators based on dielectric elastomer as one kind of EAPs exhibit excellent performances such as a great stain, heavy load drive and good plasticity, which are potential to be used widely as aptitude driver and should provide bright foreground of making actuator similar with nature muscle and the study on biology robot as well. However, a high field (almost >100kV) is required to generate such high elastic energy density in dielectric elastomers. To meet the requirement for the practical application, it is essential to improve the electro strain performance. According to the nature and mechanism of the dielectric elastomer, high dielectric constant as well as low elastic modulus is desirable for actuator materials.In this paper, silicone rubber (RTV) was selected as the polymer matrix. Titanium dioxide (TiO2), carbon black (CB) and barium titanate (BT) were selected as semiconductive filler, conductive filler and high dielectric filler, respectively. The mechanical mixing process was adopted to obtain TiO2/RTV and CB-BT/RTV nanocomposites. The dielectric properties, elastic modulus and electromechanical responses of resultant nanocomposites were studied. The results showed that the fillers' microstructure and the electromechanical responses were closely related.Firstly, CB-BT/RTV three-component nanocomposite was prepared. Due to the interaction between different fillers (the increased CB (BT) particles play a destructive role to the network structure formed by BT (CB)), the resulting three-component nanocomposits yielded very abnormal phenomenon in required properties. The results showed that by adjusting the mass fraction of BT and CB, decrease of dielectric loss and elastic modulus but increase of dielectric permittivity could be achieved. All of these factors synergistically contributed to a remarkable increase in the electromechanical strain response. These improvements may lead to the development of functional materials with improved electromechanical response.TiO2/RTV two-component composite was prepared and KH570 was adopted to modifiy TiO2. The influences of modification on dielectric properties, elastic modulus, breakdown field strength and electromechanical responses were stuied respectively. The results showd that after modificated by KH570, the interaction and compatibility between TiO2 and RTV are impressively increased, and accordingly the dielectric loss decreased, but the dielectric constant and elastic modulus increased. However, the electromechanical responses were impressively decreased because better interaction between the matrix and fillers would limit the movement of polymer chains. Research results showed that the elastic modulus have greater effect than dielectric constant on electromechanical responses.