## 3 Results and Discussion
### Water Uptake, Ion Exchange Capacity, and Conductivity  
Water uptake, ion exchange capacity (IEC), membrane thickness, and hydroxide conductivity of each membrane are listed in Table 3. These factors are crucial parameters in judging membrane performance. Water uptake, IEC, and ion conductivity were in the decreasing order of TPA > TMA > DABCO > TEA when the composition of GMA was 15% by weight. VBC predominates in the GDV15 base membrane because C-Cl bonds from VBC outnumber the epoxy rings from GMA. The GDV15-TPA had higher IEC (1.34 meq/g) than GDV15-DABCO (0.72 meq/g), which corresponded to change in water uptake from 38% to 21%. With abundant VBC, TMA is more favorable than DABCO on the base membrane,  
Figure 5: FT-IR spectra of **(a)** GDV45; **(b)** GDV45-TMA; **(c)** GDV45-TEA; **(d)** GDV45-TPA; and **(e)** GDV45-DABCO. indicating that the TPA, which have chain structure, can favorably react with VBC rather than DABCO, which have ring structure. In addition, water uptake and conductivity also show a proportional relationship. GDV15-TPA membrane displayed higher conductivity (0.022 S/cm) and water uptake (38%) compared to GDV15-DABCO (0.009 S/cm and 21% each). GDV15-TPA structure can contain hydroxide and transport it faster. GDV15 membrane quaternized by TPA exhibited higher IEC and ion conductivity than the ones quaternized by TMA and TEA. This result implies that TEA combines less with the base membrane due to greater steric hindrance compared to TMA and TPA, even though TMA, TEA, and TPA all consist of chain structure. Water uptake, IEC, and ion conductivity were in the decreasing order of TMA \(>\) TEA \(>\) DABCO \(>\) TPA when the composition of GMA was 45% by weight. Performance of GDV45-TPA membrane was the lowest among GDV45 membranes. IEC and ion conductivity of membrane quatrenized by TPA showed drastic changes from GDV15-TPA (1.34 meq/g and 0.020 S/cm) to GDV45-TPA (0.65 meq/g and 0.0091 S/cm). Therefore, the GDV45 membrane is not favorable for quatization using TPA. The IEC and ion conductivity of GDV45-TEA showed the second strongest performance among the functional group (TMA, TEA, TPA, and DABCO) due to the steric hindrance, and hydroxide having less chance to contact positive charges on the membrane quaternized by TEA compared to TMA. The water uptake in quaternized GDV45 membranes should be higher than those of quaternized GDV15 membranes. However, the result does not show a proportional relationship between water uptake and ion conductivity. The effectiveness of cross-linker (DVB) is intensified in GDV45 base membrane to a greater extent than in the GDV15 base membrane. To be more specific, the DVB shrinks the free volume in polymer structure and its effect is maximized in GDV45 base membrane. Epoxy ring and C-Cl vibration peaks did not completely disappear in Figure 4. This is also due to the effect of cross-linker (DVB). The DVB not only maintains polymer structure but also hinders reaction sites between base membrane and functional groups (TMA, TEA, TPA, and DABCO). Therefore, it will be necessary to find the optimum quaterin \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Membrane**} & **Water Uptake** & **IEC** & **Membrane** & **Conductivity (S\(\cdot\)cm\({}^{-1}\))** \\  & **(\%)** & **(meq/g)** & **thickness (mm)** & **at 60 \({}^{\circ}\)C** \\ \hline GDV15-TMA & 38 & 1.31 & 0.19 & 0.020 \\ GDV15-TEA & 24 & 0.82 & 0.18 & 0.015 \\ GDV15-TPA & 38 & 1.34 & 0.19 & 0.022 \\ GDV15-DABCO & 21 & 0.72 & 0.21 & 0.009 \\ GDV45-TMA & 35 & 0.98 & 0.19 & 0.019 \\ GDV45-TEA & 33 & 0.91 & 0.18 & 0.017 \\ GDV45-TPA & 20 & 0.65 & 0.21 & 0.0091 \\ GDV45-DABCO & 28 & 0.78 & 0.19 & 0.014 \\ GDV75-TMA & 33 & 0.93 & 0.19 & 0.018 \\ GDV75-TEA & 22 & 0.68 & 0.19 & 0.011 \\ GDV75-TPA & 31 & 0.89 & 0.18 & 0.016 \\ GDV75-DABCO & 41 & 1.34 & 0.17 & 0.021 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Properties of the anion exchange membranes. Ion conductivity of non-woven PET with pure water at 60 \({}^{\circ}\)C was \(1.52\times 10^{-10}\) S/cm.