Table 5.
Main function groups observed in FTIR spectra of hemp hurds samples (A: amorphous; C: crystalline).
| Wavenumber (cm−1) | Vibration of function group | Source |
|---|---|---|
| 3340 | OH stretching | polysaccharides |
| 2897 | C–H symmetrical stretching | polysaccharides |
| 1733 | C=O unconjugated stretching | hemicellulose |
| 1636 | OH (water) | cellulose |
| 1507 | C=C symmetrical stretching of the aromatic ring | lignin |
| 1454 | CH2 bending | lignin |
| 1422 | CH2 bending | cellulose |
| 1373 | CH bending | cellulose |
| 1337 | OH in plane bending | cellulose (A) |
| 1320 | CH2 wagging | cellulose (C) |
| 1265 | CO stretching | lignin |
| 1157 | C–O–C asymmetric bridge oxygen stretching | cellulose |
| 1028 | C–C, C–OH, C–H ring and side group vibrations | hemicellulose, pectin |
| 896 | glycosidic bonds symmetric ring-stretching mode | polysaccharides |