## 3 Result and Discussion
In other words, the dry HIX with Cu\({}^{0}\) retained less hygroscopic water than the dry anion exchanger (which means that the Cu\({}^{0}\) deposit acted as a water-repellent). Figure 1: Thermogravimetry (TG)//derivative thermogravimetry (DTG) curves in air of (**a**) M/Cu\({}_{2}\)O, (**b**) M/Cu. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Symbol of HIX**} & \multirow{2}{*}{**Water Mass Loss, \%**} & \multicolumn{2}{c}{**Peak Temperature of**} & \multirow{2}{*}{**End Temperature, \({}^{\circ}\)C**} & \multirow{2}{*}{**Residual Mass, \%**} \\  & & **Polymer Degradation, \({}^{\circ}\)C** & & \\ \hline \multicolumn{5}{c}{Decomposition in air} \\ M/Cu\({}_{2}\)O & 10.66 & 204.1, 326.9, 433.5, 549.6 & 579.0 & 11.45 \\ M/Cu & 7.17 & 201.0, 366.1, 538.4 & 554.2 & 8.49 \\ G/Cu\({}_{2}\)O & 9.36 & 204.4, 327.7, 434.6, 4.88 & 590.9 & 13.60 \\ G/Cu & 4.28 & 204.0, 321.6, 425.6, 497.1 & 517.6 & 12.71 \\ \multicolumn{5}{c}{Decomposition in N\({}_{2}\)} \\ M/Cu\({}_{2}\)O & 13.61 & 245.3, 448.4 & 467.4 & 31.21 \\ M/Cu & 8.54 & 201.6, 448.9 & 469.4 & 28.51 \\ G/Cu\({}_{2}\)O & 13.22 & 196.5, 446.6 & 466.0 & 26.83 \\ G/Cu & 6.76 & 207.4, 435.8 & 456.4 & 24.31 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Statement of thermal decomposition results. Figure 2: TG/DTG curves in air of (**a**) G/Cu\({}_{2}\)O, (**b**) G/Cu. Characteristically, the G/Cu samples contained less hydration bound water than the M/Cu samples. This can be explained by the fact that cross-linking reduces the retention of water in ion exchange resins. Gel-like anion exchangers contain less cross-linking agent (about 8% DVB) than macroreticular ion exchangers (about 15% DVB) and the fewer cross linkages an anion exchanger contains, the greater are its elasticity and swelling (this is why gel-like anion exchangers swell much more than macroreticular anion exchangers). Swelling and shrinking are reversible processes and are indeed accompanied by uptake/expulsion of water molecules [29; 39]. Therefore one could suppose that in the presence of the water repelling agent the gel-like anion exchangers having a more elastic matrix shrank more than the macroreticular ones (the osmotic force and the elastic force act in opposite directions). One might expect that the HIXs with Cu\({}_{2}\)O were poor in hygroscopic water too. The results confirmed this assumption only to a certain extent (Figures 1a and 2a). The TG/DTG curves showed that the decrement in mass due to water evaporation for M/Cu\({}_{2}\)O (10.7%) and G/Cu\({}_{2}\)O (9.4%) was larger than in previously described experiments for HIXs with Cu\({}^{0}\). This is in agreement with the FTIR analysis results for the examined materials, indicating that after the reduction of Cu\({}_{2}\)O to Cu\({}^{0}\) the area of the broad peak indicative of adsorbed water at 3350 cm\({}^{-1}\) decreased and almost vanished in the case of G/Cu [33]. One of the causes of the higher hygroscopicity of M/Cu\({}_{2}\)O and G/Cu\({}_{2}\)O in comparison with M/Cu and G/Cu could be the presence of functional groups in the OH\({}^{-}\) form, which shows a very strong affinity for water [39]. It is worth mentioning than the HIXs with Cu\({}_{2}\)O particles contained clearly less hydration bound water (about 10%) than the HIXs with CuO particles (about 13%) [31]. In order to find out whether the fine particles precipitated in the polymeric skeleton of an anion exchanger affected its thermal decomposition (styrene-divinelbenzene copolymer with functional groups), the TG/DTG curves recorded at higher temperatures (after water evaporation) were compared. As Figures 1 and 2 show, the thermal decomposition in air of the samples with Cu\({}^{0}\) ended faster (at a lower temperature) than that of the samples with Cu\({}_{2}\)O, and both the composites lowered the polymeric phase decomposition end temperature in comparison with the parent resins (the anion exchangers with no deposit) [31].