## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Temp. (\({}^{\circ}\)C)** & **T** & **T/A (1:1, _v/v_)** & **A** \\ \hline
50 & (a) 14.2 & (a) 46.7 & (a) 165.1 \\  & (b) 1.0 & (b) 6.8 & (b) 10.7 \\ \hline
70 & (a) 34.7 & (a) 103.8 & (a) 340.2 \\  & (b) 2.3 & (b) 13.2 & (b) 37.9 \\ \hline
110 & (a) 168 & (a) 388.5 & (a) 1500 \\  & (b) 44 & (b) 70.2 & (b) 260.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Solubilities of CuBr/Bpy **(a)** and CuBr\({}_{2}\)/Bpy **(b)** (units: ppm). Figure 1: Solubility tests of **(a)** CuBr/Bpy and **(b)** CuBr\({}_{2}\)/Bpy catalysts at various temperatures and solvent polarities. with respect to time (_t_), we could obtain the activation rate constants of each mixing system (_i.e._, \(k_{\text{EBiB}}\) and \(k_{\text{BzCl}}\)). We performed the kinetic experiments under pseudo-first-order conditions, using a large excess of the alkyl halide and nitroxide. In all cases, the activation rate constants of EBiB were higher than those of BzCl. The ratios of the activation rate constants (_i.e._, \(k_{\text{EBiB}}\)/\(k_{\text{BzCl}}\)) were approximately greater than 35, implying significant differences in reactivity for the copper complex with the two initiators. Notably, activation rate constants in Figure 2a,d even reached a difference of about an order of magnitude. These results indicate that the reaction temperature and solvent polarity retained their significant influence over the reactivity even at such a high difference in molar ratio of the tertiary bromoester and benzyl chloride co-initiator system. According to the related reactivity and activation rate constants, the radicals could be generated initially from the EBiB initiator with consumption of the Cu(I)/L complex under conditions of a lower temperature and a less polar solvent. Table 2 summarizes the results of the model reactions. Next, we examined AT-SCVP in a single solvent. Figure 3 displays the results of our investigations of the AT-SCVP of St and VBC in T and A at various temperatures (50, 70, and 110 \({}^{\circ}\)C). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{\(k_{\text{set}}\) (M-1-min-1)} & \multicolumn{2}{c}{**50 \({}^{\circ}\)C**} & \multicolumn{2}{c}{**70 \({}^{\circ}\)C**} & \multicolumn{2}{c}{**110 \({}^{\circ}\)C**} \\ \cline{2-7}  & **T** & **A** & **T** & **A** & **T** & **A** \\ \hline EBiB & \(1.44\times 10^{-2}\) & \(2.87\times 10^{-2}\) & \(4.77\times 10^{-2}\) & \(6.20\times 10^{-2}\) & \(5.89\times 10^{-2}\) & \(8.07\times 10^{-2}\) \\ BzCl & \(1.50\times 10^{-4}\) & \(3.00\times 10^{-4}\) & \(6.00\times 10^{-4}\) & \(1.25\times 10^{-3}\) & \(1.20\times 10^{-3}\) & \(2.44\times 10^{-3}\) \\ \(k_{\text{EBiB}}\)/\(k_{\text{BzCl}}\) & 96.1 & 95.2 & 79.5 & 49.5 & 49.1 & 35.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Activation rate constants (\(k_{\text{act}}\)) for EBiB (\(k_{\text{EBiB}}\)) and BzCl (\(k_{\text{BzCl}}\)) mixed systems under various conditions. Figure 2: Model reactions of atom transfer radical with TEMPO (AT-TEMPO) with EBiB and BzCl mixed initiators (EBiB/BzCl/CuBr/Bpy/TEMPO = 5/80/1/2/10, [EBiB]\({}_{0}\) = 0.25 M; \(C_{0}\): initial activator concentration (conc. ); \(I_{0}\): initial initiator conc. ; (**a–c**): reactions in T and (**d–f**): reactions in A. When considering the same solvent (Figure 3a,b for T; Figure 3c,d for A), VBC underwent both faster polymerization and higher conversion than did St at each temperature, consistent with that the reactivity of VBC being slightly higher than that of St (\(r_{\rm VBC}/r_{\rm St}\approx 2.0\)) [63,64]. When considering the same monomer (Figure 3a,c for St; Figure 3b,d for VBC), the polymerizations in A were faster and occurred with higher conversions at the various temperatures than did those in T, due to the higher-polarity solvent accelerating the reaction rate.