Table 1: Assignment of the IR spectra bands of functional groups in acetylated wood flour treated with acetic anhydride.

Band position (cm−1)Functional group

3973–3352 –OH bonded stretching vibrations
1746–1731 C=O stretching vibrations of acetate group
2938–2917 C–H methyl and methylene group
1373–1369 (–C–CH3–) in acetate group due to acetylation
1285–1241 ( ) stretching band vibrations of the acetyl moieties
1628–1618 –OH of absorbed water
1527–1511 (C=C), aromatic skeletal absorption caused by lignin
1044–1042 C–O stretching vibrations in cellulose, hemicelluloses, and primary alcohol
1052C–O stretching in acetyl (covalence vibration)
620–603 C–H out-of-plane stretching absorption of aromatic ring vibrations caused by lignin