## 4 Results and Discussion  
### Temperature Sweep  
The viscoelastic properties for the different composites' configurations from the temperature sweep at a frequency of 1 Hz are plotted in Figure 2. As mentioned earlier, the glass transition temperature, \(T_{g}\), can be found from either the first inflection point of the storage modulus curve or the peak of loss modulus, or the peak of the _tan\(\delta\)_ curve. During glass transition, the polymer molecular segments absorb heating energy and begin to move. However, the presence of the nanofillers diminishes the available space that would allow the molecular movement, thus more energy (and higher temperature) is needed to go around these hurdles. As seen in Table 1, there are significant differences between the \(T_{g}\) values calculated from _tan\(\delta\)_, vis-a-vis those calculated from the loss modulus peaks. When the _tan\(\delta\)_ curves were considered, the composite configuration with both CNTs and ZnO achieved the highest value for \(T_{g}\) at 82 \({}^{\circ}\)C. A similar trend was not observed from the loss modulus curves. The configuration with raw carbon fibers is seen to have the highest value of \(T_{g}\) at 73.3 \({}^{\circ}\)C.  
As seen in Table 2, the addition of nano-fillers significantly improves the _tan\(\delta\)_ values. The highest increase of 11% was observed when both CNTs and ZnO were deposited at the interface of the carbon \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Configuration** & **Loss Modulus Peak (\(T_{g}\)) in \({}^{\circ}\)C** & **Tan Delta Peak (\(T_{g}\)) in \({}^{\circ}\)C** & **Difference \%** \\ \hline Just CF & 73.37 & 77.2 & 5 \\ CF and ZnO & 73.28 & 79.33 & 7.6 \\ CNT and CF & 71.5 & 76.88 & 7.0 \\ CNT and ZnO & 72.77 & 82.06 & 11.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of glass transition temperature of the different composites’ configurations. CF: Carbon fiber; CNT: Carbon nanotubes; ZnO: Zinc Oxide nanorods. fabrics layers. This can be clearly seen in Figure 2a. This trend was not observed when only CNTs were added to the interface, which could be attributed to poor dispersion of CNTs in the sample, as seen in the SEM micrograph of Figure 1c. This agglomeration can result in early delamination or poor mechanical characteristics. This might also be a consequence of CHP utilized for the dispersion of CNTs [52]. There is a possibility these groups form bonds with epoxy and effect the cross-linking of resin with the fiber. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Configuration**} & \multirow{2}{*}{\begin{tabular}{c} **Change in Tan Delta** \\ **(Peak Values, \%)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Change in Loss** \\ **Modulus** \\ **(Peak Values, \%)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Change in Storage** \\ **Modulus** \\ **(at 60 \({}^{\circ}\)C, \%)** \\ \end{tabular} } \\ \hline CF and ZnO & 10.04 & \(-\)18.26 & \(-\)25.95 \\ CNT and CF & \(-\)9.82 & \(-\)25 & \(-\)26.44 \\ CNT and ZnO & 10.98 & 15.53 & 25.51 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of the performance of the various composites’ configurations with respect to the composite based on CF under temperature sweep. Figure 2: _Cont._  
In the presence of ZnO and CNTs, both loss and storage moduli show a significant improvement of 16% and 26%, respectively, as shown in Table 2. These trends are shown in Figure 2b,c. This implies that the composite exhibits improvement in both viscous and elastic properties. This trend was not observed for composites comprising individual fillers where they exhibited considerable drop in both moduli. This can be attributed to the diminishing space for molecular movements due to the high density of nanofillers in the sample that has both nanofillers. The composites with individual fillers demand a uniform distribution of nanorods or nanotubes to show improvement in this aspect.