“…In addition, the absorptions at 1,020 to 1,050 cm −1 and 1,070 to 1,110 cm −1 indicate the C-O stretching vibrations in chitosan, which are associated with the C6-OH primary alcohol and the C3-OH secondary alcohol, respectively, and the bands at 1,160 and 996 cm −1 are assigned to the vibrations of the C-O-C saccharide bridge [ 36 ]. The modification of chitosan with the ethylene glycol (EG) moiety introduced chemical groups in the polymer chain (G-CHI) such as ether (C-O-C, 1,150 to 1050 cm −1 ), alcohol (−C-O, 1,260 to 1,000 cm −1 ), alkane (CH, 2,960 to 2,850 cm −1 and 1,450 to 1,300 cm −1 ), and hydroxyl (OH, 3,600 to 3,200 cm −1 ) [ 37 , 38 ], which mostly overlap the chitosan absorption bands. In addition to these bands, in the spectrum of the as-supplied glycol chitosan, the vibrations at 945 and 892 cm −1 , associated with –CH 2 rocking [ 37 ] and the –OC 2 H 4 backbone [ 38 ], respectively, were observed.…”