## 3 Results and Discussions  
### Samples Characterization  
In the present study, through a facile one-pot strategy, [(diethyl)](phosphono) methylelen]glycine pendant groups and [(diphenyl)(phosphono)methylene]glycine pendant groups grafted on styrene-6.7% divinylbenzene copolymers were prepared successfully using amino acid, diethylphosphite/dibenzylphosphite and aldehyde copolymers as matrix (see Scheme 1).  
Within the limits of inherent experimental errors, Table 1 present the results obtained in the characterization of the functionalized copolymers by determining the phosphorus and nitrogen content.  
In Figure 1a, it is seen that the beads exhibit as a perfect ball, with the diameter varying from 476 \(\upmu\)m to 864 \(\upmu\)m. In addition, in Figure 1b, it is seen that the sample has a rough surface and uniform distribution of pores.  
The comparative interpretation of the IR spectra (Figure 2) for the synthesized samples (EthylAmAcid and BenzylAmAcid) and aldehyde support shows a decrease in the intensity of the aromatic aldehyde groups' absorption band at 1697 cm\({}^{-1}\), corresponding to C=O stretching at the aromatic nucleus, confirming that the reaction occurred at the aromatic aldehyde groups. It also shows a slight increase in the adsorption band intensity from 1592 cm\({}^{-1}\), indicating the presence of N-H valence vibrations, and shows that the aliphatic P-O-C stretch causes an increase in the intensity of the adsorption band at 1017 cm\({}^{-1}\).  
The comparative interpretation of the TG spectra (Figure 3) for the synthesized sample (EthylAmAcid) and aldehyde support shows that after 900 \({}^{\circ}\)C, the decomposition of EthylAmAcid sample gives 19.3% residue; that after 900 \({}^{\circ}\)C, the aldehyde support shows better stability, and at decomposition it gives 34% residue; and that the EthylAmAcid sample has stability up to a temperature of 260 \({}^{\circ}\)C compared to aldehyde support, which is stable up to a temperature of 420 \({}^{\circ}\)C.  
\begin{table}
\begin{tabular}{c c c} \hline
**Elem./Wt\%** & **EthylAmAcid Sample** & **BenzylAmAcid Sample** \\ \hline C & 72.1 & 80.5 \\ \hline N & 4.55 & 2.24 \\ \hline O & 21.7 & 16.1 \\ \hline P & 1.51 & 1.11 \\ \hline Cl & 0.141 & 0.0103 \\ \hline \end{tabular}
\end{table}
Table 1: EDX for [(diethyl)(phosphono)methylene] glycine pendant groups/[(dibenzyl)(phosphono) methylene]glycine pendant groups grafted on copolymer. (Code: EthylAmAcid/BenzylAmAcid.)Thus, upon the introduction by functionalization of \(\beta\)-phosphonate glycine pendant groups, the EthylAmAcid sample becomes less stable compared to the raw material.  
Figure 1: SEM images for [(diethyl)](phosphono)methylenelglycine pendant groups grafted on copolymer (Code: EthylAmAcid): (**a**) polymer beads at 50\(\times\) magnitude; (**b**) rough surface of a bead at 10,000\(\times\) magnitude.  
Figure 3: TG analysis for EthylAmAcid sample and aldehyde support.  
Figure 2: FTIR for EthylAmAcid, BenzylAmAcid samples and aldehyde support.  
The UV-VIS spectra for the samples are presented in Figure 4. The spectra present a broad absorption band in the UV domain, with two shoulders at 260 and 320 nm, that originate from the intra-aromatic \(\pi\)-\(\pi^{\bullet}\) transitions in copolymer [21]. The direct allowed band gap energies, calculated from the Kubelka-Munk transformed diffuse reflectance spectra, are 3.60 eV for EthylAmAcid sample and 3.65 eV for BenzylAmAcid sample. The values of band gap energies are in the domain of the energies calculated for other polymers [22; 23]. The type of the groups, [(diethyl)(phospho)methylene]glycine pendant groups or [(diphenyl)(phospho)methylene]glycine pendant groups, grafted on copolymer does not lead to obtaining very different values for the band gap energy. The small variation band gap energy for these structures may be due to the subtle difference in their structural arrangement. It is expected that the behavior of the samples will be similar in the process of heterogeneous photocatalysts.