## 3 Results
### Thermomechanical Measurements on PS-CNWs Nanocomposites  
Dynamic mechanical analysis (DMA) measurements provide information regarding the effect of nano-addition into the polymer chains mobility, the glass transition temperature (T\({}_{\rm g}\)), as well as the storage modulus (E'), loss modulus (E\") and loss factor (tan\(\delta\)) of a polymer above and below the T\({}_{\rm g}\)[37]. The results of the DMA measurements are presented in Figure 11 and in Table 2.  
As observed pristine PS exhibits a decrease in E' starting at app. 50 \({}^{\circ}\)C. The lowering of the E' of the un-reinforced PS is also observed as a shoulder in the tan\(\delta\) curve (Figure 11b) located in the range of 60-80 \({}^{\circ}\)C, i.e., at temperatures well below the T\({}_{\rm g}\) of the PS, associated with some side groups movement, such as phenyl groups. Based on Figure 11, it is obvious that the addition of nanowires results in alteration of the thermomechanical response of the PS matrix, both in terms of E' and tan\(\delta\). As observed in Figure 11a, CNW-based PS nanocomposites retain a constant E' up to app. 80 \({}^{\circ}\)C, where the transition from the glassy to the rubbery state begins. Contrary to plain PS, CNW reinforced specimens do not present any shoulder in their tan\(\delta\) spectra in the respective area. It seems that CNW particles interact with the sidechains of PS restricting their mobility, and only one main transition (the one associated with the T\({}_{\rm g}\)) is being observed. The higher the CNW content, the higher is the value of E' in the glassy state. This increase is more pronounced for CNW contents of 3% and 5 wt%. It is also important to note that PS-CNWs-3%, even after the glass transition (rubbery state) exhibits much higher values in E' (\(\sim\)100 MPa) compared to other samples, having E' \(\sim\)20-30 MPa. The pronounced increase in E' in both the glassy and the rubbery state for a 3% reinforcement, demonstrates the good interaction of the nanowires with the PS matrix, thus creating a strong interface that leads to a clear reduction of chain mobility both below and above the Tg. The increase in E' for T \(<\) Tg, (i.e., the matrix is a pure solid from a mechanical point of view), is simply explained based on what generally happens when reinforcing solid matrices with fibers, CNTs, etc. The increased modulus of elasticity in the rubbery state means that there are also some quite strong matrix-nanowires connections, and these connections contribute to the modulus of elasticity of the material as equivalent to the cross-linking of the matrix. These results agree with the stiffness ones, confirming the vital role of dispersion in the thermo-mechanical performance of the nanocomposites. As seen in Figure 11b, the T\({}_{\rm g}\) for the PS prior to the addition of carbon nanowires may be positioned at 105 \({}^{\circ}\)C (main transition), or perhaps slightly lower, to a relatively satisfactory agreement with the literature [38]. In parallel, the addition of CNWs seems to decrease the glass transition temperature by \(\sim\)3 \({}^{\circ}\)C, at least if we accept that differences in temperatures of the maximum tan\(\delta\) reflect differences in the T\({}_{\rm g}\) value (Table 2). In this case, one usually resorts to interpret the alleged lowering the Tg, in reference to the Tg dependence on the molecular weight of the chains (which herein may be reduced, for obscure reasons, by the presence of nanowires) and the possible presence of small molecule impurities [39]. However, in the present case, it is preferable to avoid referring to a hypothetical specific reason of \"lowering of the Tg\" because the temperature difference of 3 \({}^{\circ}\)C (Table 2), combined with the much higher peak tan\(\delta\) range, allows for a variety of interpretations of chain relaxation and Tg.