RTV silicone rubber composites reinforced with carbon nanotubes, titanium-di-oxide and their hybrid: Mechanical and piezoelectric actuation performance

The use of nanofillers with high surface area and extreme purity in polymer composite is an effective strategy to obtain high performance polymeric nanocomposites. Therefore, the effect of nanofillers such as carbon nanotubes (CNT), titanium dioxide (TiO2), and their hybrid on rubber-based composites was studied. In this study, rubber nanocomposites were fabricated by using room temperature vulcanized (RTV) silicone rubber matrix and nanofillers (i.e. CNT, TiO2, and CNT-TiO2) through solution casting method. Here, the purity and surface area of CNT (purity: >96% and BET surface area: 300 m2/g) and TiO2 (purity: >98% and BET surface area: 165 m2/g) were estimated by field emission scanning electron microscopy/energy dispersive X-ray (FESEM-EDX) and adsorption isotherms. The mechanical properties of the rubber nanocomposites were enhanced by incorporating nanofillers. The compressive modulus was 2.18 MPa for unfilled composites and increased to 6.8 MPa (CNT), 3.95 MPa (CNT-TiO2), and 2.44 MPa (TiO2) at 5 phr, respectively. Similarly, the tensile strength was 0.54 MPa for unfilled composites and increased to 1.37 MPa (CNT), 1.33 MPa (CNT-TiO2) and 0.61 MPa (TiO2) at 5 phr, respectively. Further, the actuation displacement was improved with increasing input voltage and it was 2 mm for CNT, 1.6 mm for CNT-TiO2 hybrid and 0.5 mm for TiO2 at 10 kV. Moreover, a series of experiments show the potential application in piezoelectric actuation.