# Preparation Methods and Properties of CNT/CF/G Carbon-Based Nano-Conductive Silicone Rubber
## 3 Results and Discussion
### Properties of the PREPARED Single-Filler Conductive Silicone Rubbers
[22] found that in a certain range, with the increase of CF load, CF is not always surrounded by SR matrix, which makes the interaction between filler and matrix weak. Therefore, both tensile strength and elongation at break decrease. When the carbon fiber content exceeds 7.5 wt%, the mechanical properties tend to decrease rapidly. When the mass fraction of carbon fiber reaches 25.5 wt%, the tensile strength is 1.81 Mpa, the elongation at break is 85.9%, and the elastic modulus is 0.36 MPa. Compared with 7.5 wt% carbon fiber, the tensile strength, elastic modulus, and elongation at break of carbon fiber conductive silicone rubber decreased by 0.41 MPa and 0.02 Mpa, respectively, from 90.6% to 85.9%. Therefore, under the experimental conditions of a single carbon fiber-filled silicone rubber, the carbon fiber conductive silicone rubber with a mass ratio of 5.5-7.5 wt% has better mechanical properties. The tensile strength of spherical boron nitride 10/pitch-based carbon fiber 20/silicone rubber (s-BN10/PCF20/SR) prepared by reference [23] is 1.08 MPa, which is obviously lower than the tensile strength of 7.5 wt% carbon fiber conductive silicone rubber prepared in this paper (2.12 MPa), which indicates that the carbon fiber conductive silicone rubber prepared in this paper has good mechanical properties. Dispersion and heat resistance analysis of LSR/CF. According to the analyses of the electrical and mechanical properties, the ideal CF concentration is 5.5-7.5 wt%. Thus, LSR/CF with 7.5 wt% CF was tested, and its properties were comprehensively analyzed. Dispersion analysis  
Figure 3 displays the Raman spectra of LSR/CF. In the figure, for pure LSR, the peak at 1340 cm\({}^{-1}\) is ascribed to -CH2 bending and that at 2899 cm\({}^{-1}\) is the characteristic peak of -CH2 stretching vibration. For LSR/CF, the bending and stretching vibration characteristic peaks of -CH2 were also observed at 1340 and 2899 cm\({}^{-1}\), which proves that CF has good dispersion performance in conductive silicone rubber. Figure 3: Raman spectra of pure LSR and LSR with 7.5 wt% CF. (2) Heat resistance  
The thermogravimetric analysis diagram of LSR/CF with 7.5 wt% CF is shown in Figure 4.  
The corresponding temperature when losing 5%, 10%, and 50% of mass due to high temperature is T\({}_{\rm d.5\%}\), T\({}_{\rm d.10\%}\), and T\({}_{\rm d.50\%}\), respectively, and Tmax occurs when reaching the highest experimental temperature of 700 \({}^{\circ}\)C. As shown in Figure 4, the mass of LSR/CF rapidly decreased with increasing temperature, and the mass loss stabilized when the combustible substances were completely burned. For a CF concentration of 7.5 wt%, the T\({}_{\rm d.5\%}\), T\({}_{\rm d.10\%}\), and T\({}_{\rm d.50\%}\) of the conductive silicone rubber were 457 \({}^{\circ}\)C, 523 \({}^{\circ}\)C, and 708 \({}^{\circ}\)C, respectively, and the corresponding temperature and weight loss at Tmax were 779 \({}^{\circ}\)C and 48.05%, respectively. For pure LSR, T\({}_{\rm d.5\%}\), T\({}_{\rm d.10\%}\), and T\({}_{\rm d.50\%}\) were 441 \({}^{\circ}\)C, 520.1 \({}^{\circ}\)C, and 789.7 \({}^{\circ}\)C, respectively, and the corresponding temperature and weight loss at Tmax were 789.7 \({}^{\circ}\)C and 50.75%, respectively. When LSR/CF initially decomposed under the influence of temperature, its tensile sensitivity gradually decreased. The initial decomposition temperature of LSR/CF was 457 \({}^{\circ}\)C, which is 16 \({}^{\circ}\)C higher than that of pure LSR, indicating that CF improves the heat resistance of the silicone rubber. (2) Properties of graphene conductive silicone rubber  
Graphene conductive silicone rubber (LSR/G) with a graphene content of 1.5, 2.5, 3.5, 5.5, 7.5, 8.5, 9.5, and 11.5 wt% was prepared and its properties were analyzed. The ratio of silicone rubber to n-heptane was kept unchanged at 1:2.