## 3 Results and Discussion
EL-e lignin fraction had a less condensed macromolecular structure with a high content of phenolic and aliphatic hydroxyl groups  
Figure 2: ATR/FTIR spectra of polymers with (**a**) SL-ea, (**b**) SL-m, (**c**) EL-ea, and (**d**) EL-e.  
in phenylpropanol units, as shown in Table 1. The higher percentage of these groups as compared to softwood lignin fraction could react with methacryloyl chloride [29], and this could give a more homogeneous distribution of methacrylic groups in the lignin macromolecules and a more crosslinked network in the final microspheres. The inclusion of styrene, however, led to a decrease in porosity. Figure 4 shows the pore size distribution of the materials, which reveals more information about the porosity. All the materials are mesoporous. The pore size distributions are bimodal with a narrow peak with a maximum at 3 nm and a broader peak with a maximum at 12-50 nm. The presence of modified lignin in the structure of microspheres results in a shift of the second peak toward a lower value suggesting the creation of narrower, deeper, and more uniform pores in the material. The larger the amount of modified lignin used, the narrower and deeper the pores are in the materials. The fractionated lignin results in a greater porosity of the synthesized materials than in the microspheres where commercially available and low molecular weight lignin was applied [50]. The results of swelling studies of the polymer materials are presented in Table 5. The lowest swellability coefficients were obtained for the polymers with EL-e lignin, which can be related to its crosslinking ability. Ethyl acetate fractions of lignin (SL-ea and EL-ea) had a higher swellability coefficient than EL-e and SL-m. Except for the materials with EL-e lignin, the greatest swelling tendency was observed in the materials with styrene and unmodified lignin. An increase in lignin content usually led to an increased swelling. In general, crosslinked materials have a low tendency to swell, but the presence of functional groups from lignin caused networks to interact with the solvents. None  
Figure 3: DSC curves of polymers containing (a) SL-ea, (b) SL-m, (c) EL-ea, (d) EL-e.  
of the microspheres swelled in distilled water. The highest swelling coefficients were obtained in acetone and chloroform. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Polymer** & **S\({}_{\textbf{BET 1 (m^{2}/g)}}\)** & **V\({}_{\textbf{TOT 2 (cm^{3}/g)}}\)** & **D\({}_{\textbf{A 3 (nm)}}\)** \\ \hline SL-ea-Met + St + DVB & 51 & 0.104 & 8.2 \\ SL-ea + St + DVB & 139 & 0.597 & 17.1 \\
1 SL-ea-Met + DVB & 103 & 0.126 & 4.9 \\
2 SL-ea-Met + DVB & 396 & 0.700 & 7.1 \\
3 SL-ea-Met + DVB & 314 & 0.542 & 6.9 \\
2 SL-ea + DVB & 416 & 0.996 & 9.6 \\ \hline SL-m-Met + St + DVB & 291 & 0.983 & 13.5 \\ SL-m + St + DVB & 23 & 0.077 & 13.2 \\
1 SL-m-Met + DVB & 474 & 1.405 & 11.9 \\
2 SL-m-Met + DVB & 442 & 0.969 & 8.8 \\
3 SL-m-Met + DVB & 462 & 0.803 & 6.9 \\ \hline EL-ea-Met + St + DVB & 229 & 0.517 & 9.0 \\ EL-ea + St + DVB & 30 & 0.080 & 10.6 \\
1 EL-ea-Met + DVB & 384 & 0.937 & 9.7 \\
2 EL-ea-Met + DVB & 434 & 0.953 & 8.8 \\
3 EL-ea-Met + DVB & 62 & 0.083 & 5.4 \\
2 EL-ea + DVB & 212 & 0.802 & 15.1 \\ \hline EL-e-Met + St + DVB & 410 & 0.938 & 9.1 \\ EL-e + St + DVB & 195 & 0.785 & 16.1 \\
1 EL-e-Met + DVB & 394 & 0.996 & 10.1 \\
2 EL-e-Met + DVB & 506 & 1.342 & 10.6 \\
3 EL-e-Met + DVB & 483 & 0.981 & 8.1 \\
2 EL-e + DVB & 299 & 1.135 & 15.2 \\ \hline \hline \end{tabular}  
* \({}^{1}\) specific surface area, \({}^{2}\) total pore volume, \({}^{3}\) and average pore diameter.  
\end{table} 
Table 4: Pore structure parameters of the polymers.