## 3 Results and Discussions
### Thermal Properties Analyses and SEM  
Thermal conductivity is one of the key factors for shape memory composites, and the high thermal conductivity favors a reduction in the shape recovery time of the SiCw/hydro-epoxy composites. Figure 4 reveals that the thermal conductivity of the composites was improved with the addition of SiCw filler, and the thermal conductivity increased with increasing SiCw content. This is because, when SiCw content is low, few SiCws are in contact with each other, and thermal conductivity is slightly improved [30]. However, with an increase in SiCw content (>12 wt %), the probability of the thermal conductivity chain and thermal conductivity network increased. Thus, the thermal conductivity increased significantly.  
Dynamic mechanical analysis (DMA) is can not only be used to characterize the mechanical properties of polymers in different temperature fields, but also characterize the glass transition temperature of \(T_{\text{g}}\). The \(T_{\text{g}}\)s of the SiCw/hydro-epoxy composites are the peaks of the \(\tan\delta\) curves, as shown in Figure 5. The storage modulus of the SiCw/hydro-epoxy composites are shown in Figure 6. \(T_{\text{g}}\) is an important parameter of the themomechanical properties and the shape memory effect of shape memory polymer composites. In this work, the shape memory transition temperature is glass transition temperature (\(T_{\text{g}}\)). From Figure 5, it can be found that the \(T_{\text{g}}\) values of the SiCw/hydro-epoxy  
Figure 3: Tensile strength of the SiCw/hydro-epoxy composites.  
Figure 2: Bending strength of the SiCw/hydro-epoxy composites.  
composites slightly decrease with increasing SiCw content. This phenomenon is due to the addition of the whiskers, reducing the crosslinking density of the epoxy resin, and increasing the peristalsis ability of the molecular chain in the curing network, which leads to the decrease in the \(T_{\mathrm{g}}\) values of the SiCw/hydro-epoxy composite.  
Figure 4: Thermal conductivity of SiCw/hydro-epoxy composites with different SiCw amounts.  
Figure 5: Tan \(\delta\) curves of SiCw/hydro-epoxy composites.  
Figure 6: Storage modulus of SiCw/hydro-epoxy composites.  
The storage modulus below the shape memory transition temperature is related to the shape fixity ratio of the composites, and the storage modulus above the shape memory transition temperature is related to the shape recovery ratio [31]. It also can be found in Figure 6 that the storage modulus increases with the increase in SiCw content but decreases when SiCw content rises to 16 wt %. For further analysis, the SEM images of the samples were observed. Figure 7 indicates that, when SiCw content is lower than 12 wt %, the whiskers are dispersed in the matrix, and the whiskers cannot contact each other. The interface between the SiCws and the hydro-epoxy resin is smooth, and the fracture surface is ductile fracture. Therefore, the mechanical properties and thermal conductivity of the composites insignificantly improved. When the whisker content increased to 12 wt %, the SiCw network structure was formed in the composites, which can be useful in improving the mechanical properties and thermal conductivity of composites; however, higher SiCw content (w \(\geq\) 16 wt %) caused a serious aggregation that resulted in bubbles in the matrix, which destroy the continuous structure of the resin. Thus, the mechanical properites of the composites decreased.