Table 2.
FTIR assignments for the spectra acquired.
| Functional Group | Vila, 2011 [40] | Functional Group | Thakur, 2015 [42] | Functional Group | Thakur, 2016 [43] |
|---|---|---|---|---|---|
| Amorphous cellulose | 897 cm−1 | Vibration C=O in different spatial direction | 944 cm−1 | Stretching C–H out of plane | 852 cm−1 |
| Amorphous cellulose | 1273 cm−1 | Stretching C–O by grafting | 1244 cm−1 | Asymmetric stretch ether C–O–C | 1034 cm−1 |
| Crystalline cellulose | 1370 cm−1 | C=O vibration in different spatial direction | 1327 cm−1 | Carbonyl stretch C=O | 1276 cm−1 |
| Crystalline cellulose | 1430 cm−1 | C=O vibration in different spatial direction | 1449 cm−1 | Methoxy group C–O–CH3 | 1379 cm−1 |
| Lignin | 1460 cm−1 | Aromatic skeletal vibrations | 1449 cm−1 | Methoxy group C–O–CH3 | 1466 cm−1 |
| Lignin | 1510cm−1 | Aromatic skeletal vibrations | 1512 cm−1 | Aromatic stretching C–C bond | 1516 cm−1 |
| Lignin | 1600 cm−1 | Double substitution p-aromatic ring | 1602 cm−1 | Carbonyl stretching C–C bond | 1600 cm−1 |
| Stretching C–H | 2900 cm−1 | Double substitution p-aromatic ring | 1628 cm−1 | C=O by phenolic insertion | 1665 cm−1 |
| Face, Iα | 3267 cm−1 | Carbonyl group C=O | 1673 cm−1 | C=O by phenolic insertion | 1691 cm−1 |
| Vibrations O–H | 3290 cm−1 | Stretching C–H | 2924 cm−1 | Carboxyl group | 2500–3000cm−1 |
| Vibrations O–H | 3333 cm−1 | Vibrations O–H | 3380 cm−1 |