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Table 1 FTIR absorption bands and assignments for kraft and soda lignins

From: Synthesis of lignin based composites of TiO2 for potential application as radical scavengers in sunscreen formulation

Frequency (cm−1) [10] Assignments Frequency (cm−1)
Kraft Soda
3450–3400 O–H stretching (phenolic OH and aliphatic OH)` 3426 3411
2960–2925 C–H stretching (CH3 and CH2 groups) 2925 2938
2855–2840 C–H stretching (OCH3) 2851 2842
1715–1705 C=O stretching (unconjugated ketone, carbonyl and ester groups) 1711 1708
~ 1600 C–C stretching (aromatic skeleton) 1606 1604
1513 C–C stretching (aromatic skeleton) 1512 1513
1460 C–H deformation (asymmetric in –CH3 and –CH2) 1462 1459
1425 C–C stretching (aromatic skeleton) with C-H in-plane deformation 1424 1425
1270 C–O stretching vibration of secondary alcohol 1274 1267
~ 1220 C–O(H) + C–O (Ar) (phenolic OH and ether in syringyl and guaiacyl) 1217 1213
1115 Ar–CH in plane deformation (syringyl) 1122 1117
~ 1030 C–O(H) + C–O(C) (first order aliphatic Oh and ether 1035 1030
815–795 C–H out of plane (aromatic ring) 796 814