## 5 Conclusions  
Four different configurations of triple ply composites were prepared and characterized for their damping properties. Temperature analysis showed about 11%, 16%, and 26% improvement in tan delta, loss modulus, and storage modulus, respectively, when both CNTs and ZnO nanorods co-exist in the composite. An evident trend for \(T_{g}\) variation cannot be seen when various nanofillers were added. However, it can be concluded that all the configurations have a \(T_{g}\) between 70-83 \({}^{\circ}\)C. Also, a significant variation in \(T_{g}\) of 11% between loss modulus and tan delta peaks was noted. The anticipated trend was to see an increase in glass transition when adding a nanofiller, as the nanofiller will increase the resistance of the chain movement. However, as several other articles stated, the bundling effect of CNTs often led to a decrease in the \(T_{g}\) of an epoxy. [PERSON] and [PERSON] [54] surveyed the results of 15 different investigations and have shown that that there is no clear trend to how MWCNTs affect the \(T_{g}\), and they attributed these inconclusive results to agglomeration, use of different solvents or dispersants in CNTs, and deviation in the degree of curing.  
Frequency analysis indicated that the addition of a single nanofiller is more advantageous when operated above 60 Hz. Tan delta improved from 48-85% with the addition of various nanofillers, while loss modulus improved from 30-70% due to the additives. There is a significant drop in storage modulus due to the absorbed moisture during the growth step.  
Also, the effect of frequency on the various damping variables was investigated. In general, all three viscoelastic parameters tend to increase with higher frequency. The value for \(T_{g}\) also shifts towards the right side of the graphs as frequency increases. These values were used to calculate the slope of existing linear relation between the frequency and \(T_{g}\). This was followed by the calculation of \(\Delta H\) for all four configurations. No significant variations were seen between loss modulus and tan modulus results. The values for \(\Delta H\) increased due to the addition of nanofillers, the highest being the composite with CNTs as nanofillers. This study provides proof that ZnO and CNTs as interfacial nanofillers are essential for enhancing the damping properties and decreasing the creep rate in CFRPs. However, efforts are being made for more uniform patterns of these nanofillers on carbon fabric. This can help in establishing more profound trends in \(\Delta H\) changes with the addition of nanofillers.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Configuration** & \(\Delta H\) **from tan\(\delta\) Peaks** & \(\Delta H\) **from Loss Modulus Peaks** \\  & **(k)/mol** & **(k)/mol** \\ \hline Just CF & 0.85 & 0.83 \\ CF and ZnO & 0.86 & 0.80 \\ CF and CNTs & 0.96 & 0.88 \\ CNTs and ZnO & 0.87 & 0.84 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Activation energy (\(\Delta H\)) values for the different composite configurations.  
**Author Contributions:** S.A. carried out the growth of ZnO nanorods and deposition of CNTs, manufacturing, and DMA characterization of the hybrid composites. [PERSON] guided this research, developed the technique for growth of ZnO on carbon fibers, and assisted in manufacturing and characterization of the hybrid composites.  
**Funding:** This research received no external funding.  
**Acknowledgments:** [PERSON] gratefully acknowledges the support from Embry-Riddle Aeronautical University Accelerated Research Imitative (ARI) grant.  
**Conflicts of Interest:** The authors declare no conflict of interest.