3.4. FTIR
The FTIR spectra of extracted keratin in the region
400–4000 cm−1 are given in Fig. 3, where the characteristic
absorption bands are mainly assigned to the peptide bonds CONH ). The vibrations in the peptide bonds originate bands
known as amides I–III [21–23]. The amide I band is connected
mainly with the C O stretching vibration and it occurs in the range
of 1700–1600 cm−1. The amide II band is related to N H bending
and C H stretching vibration and it falls at 1520 cm−1 region.
The amide III band occurs in the range of 1220–1300 cm−1 and it
results from in phase combination of C N stretching and in N H
in plane bending, with some contribution from C C stretching and
C O bending rations. It can be seen from Fig. 3 that these bands
exist in extracted keratin.