## 3 Results and Discussion  
By using a fractionation protocol as described in Reference [52], the kraft lignin fractions of different molecular weight but with very similar content of functional groups were produced for hardwood and softwood lignins (SL-ea vs. EL-ea and SL-m vs. EL-e) (Table 2). Generally, for each type of lignin, the fractions with higher molecular weight, SL-m and EL-e, had a higher content of aliphatic -OH groups. Hardwood lignin fractions, EL-ea and EL-e, had half as many condensed guaiacyl Ph-OH groups as corresponding softwood lignin fractions, SL-ea and SL-m, which is in accordance with previously reported results [29]. [PERSON] et al. [29] concluded that this structural feature most likely affects the chemical reactivity of lignin as a higher content of vinyl groups per lignin phenylpropanol unit was introduced on methacrylation for lignin samples that have a lower degree of condensation. Four solvent fractions of lignin were successfully modified with methacryloyl chloride, as shown in their ATR/FT-IR spectra (Figure 1a-d). After modification, a reduction in the signal intensity of hydroxyl groups at 3391-3393 cm\({}^{-1}\)[54] was observed, and new strong signals from stretching vibrations of carbonyl groups at 1726-1737 cm\({}^{-1}\) were clearly visible. The new signal at 1636 cm\({}^{-1}\) corresponding to C=C bonds [29] indicates the presence of methacrylate units in the lignin molecule, particularly in the SL-ea-Met lignin. The signals at 1120-1125 cm\({}^{-1}\) and 1032-1041 cm\({}^{-1}\) are attributed to C-O and C-O-C stretching vibrations in acrylates. The bands at 946 cm\({}^{-1}\) can be attributed to a terminal C=CH\({}_{2}\) bending vibration from the methacrylate groups in the lignin samples [55]. ATR/FT-IR spectra of the materials are presented in Figure 2a-d. The spectroscopic evaluation proved that the synthesis of lignin-containing microspheres had been successful, manifested by the presence of characteristic bands of appropriate functional groups. The increasing lignin content reflected in the increasing intensity of these bands agreed entirely with the expectations. In the spectra of the materials containing styrene, a signal was visible at 3010 cm\({}^{-1}\), which can be attributed to stretching and deformation vibrations of C-H and confirm that styrene has been incorporated into the structure of the microspheres. Bands at 2920 and 2850 cm\({}^{-1}\) can be assigned to the asymmetric and symmetric stretching vibrations of C-H in -CH\({}_{2}\)- groups [56] present in lignin, as well as in DVB and/or St. For the materials with St, signals between 3000-2780 cm\({}^{-1}\) assigned to C(sp\({}^{3}\))-H bonds are more intense due to the formation of a polymer backbone [57]. Signals at 1740 cm\({}^{-1}\) attributed to stretching vibrations of carbonyl groups were observed for the materials containing modified lignin. \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline \multirow{2}{*}{**Lignin Fraction**} & **Mn 1** & **Mw 2** & **D3** & **Aliphatic-OH** & **Carboxyl-OH** & **Phenstolic-OH** & **Phenstolic-OH (mm)/g** & \\  & **(g/mol)** & **(g/mol)** & **D3** & **(mm)/g** & **(mm)/g** & **Condensed G 4** & **Non-Condensed** & **Total** \\ \hline Spruce-ethyl acetate (SL-ea) & 720 & 1160 & 1.6 & 0.7 & 0.7 & 1.8 & 3.2 & 5.0 \\ Spruce-methanol (SL-m) & 1400 & 2900 & 2.1 & 1.8 & 0.4 & 2.0 & 2.5 & 4.5 \\ Exachyplus-ethyl acetate (EL-ea) & 630 & 940 & 1.5 & 0.6 & 0.3 & 0.8 & 4.1 & 4.9 \\ Exachyplus-ethanol (EL-e) & 870 & 1420 & 1.6 & 1.4 & 0.4 & 0.9 & 3.5 & 4.4 \\ \hline \hline \end{tabular}  
* Number average molecular weight, 2 weight average molecular weight, 3 and polydispersity index. 4 Guaiacyl,
* syringyl.  
\end{table} 
Table 2: Molecular weight characteristics and content of functional groups in lignin solvent fractions. The absorption peaks at 1596 and 1510 cm\({}^{-1}\) can be assigned to C = C of aromatic skeletal vibrations from lignin, DVB, and/or St.