Table 8.

The characteristics of the main absorbance spectra in FTIR of flax fibers.

Bond	Vibration Type	Wavenumber [cm−1]	Remarks
O-H	Stretching	3100–3600	Cellulose, hemicellulose, lignin, pectin
C-H, C-H2	Stretching	2853–2921	Cellulose, hemicellulose, lignin, pectins, waxes, and fats
C=O	Stretching	1730–1738	Carboxylic acids, aldehydes, esters (pectin, lignin, waxes and fats)
O-H	Stretching	1620–1641	Adsorbed water
C=C	Stretching	1509	Pick characteristic for lignin
O-H C-H3 and C-H2	Bending Deforming	1454 1464–1473	Adsorbed water Lignin and cellulose, hemicellulose, pectins, waxes, and fats
COO	Stretching	1428	Acids (pectins)
O-H	Bending	1335	Cellulose, hemicellulose, lignin, pectin
CH2	Scissoring (bending)	1315	Cellulose, hemicellulose
C-O	Stretching	1249	Hemicellulose, pectins
C-H	Bending	1204	Flax, hemp
C-O-C C-O	Bending Stretching	917–1186	Cellulose, hemicellulose, pectin
1,4-β-Glycosidic bond	Stretching	896	Cellulose, hemicellulose, pectin