Enhancement of Hydrophobicity of Fish Skin Gelatin via Molecular Modification with Oxidized Linoleic Acid
Table 1
Functional group assignment on major absorption bands occurring in the infrared spectra of nonoxidized linoleic acid (LA) and oxidized linoleic acid (OLA).
Wavenumber (cm−1)
Type of vibration and functional group
LA
OLA
3350–3120
Stretching of OH in fatty acid
3600–3200
Stretching of OH in aldehyde, peroxide coupled with OH of fatty acid
3009
3009
CH stretching of cis-double bond (=CH)
2954
2954
Asymmetric stretching vibration shoulder of the aliphatic CH3 group
2926, 2854
2926, 2854
Asymmetric and symmetric stretching, respectively, of aliphatic CH2 group
—
1745
Stretching vibration of C=O of aldehyde and ester
1715
1715
Stretching of C=O of fatty acid
1654
1654
C=C stretching vibration
1465, 1458
1465, 1458
Bending vibration of aliphatic CH2, CH3, respectively
1420
1420
Rocking vibration of CH bonds of cis-distributed olefins
1238, 1175–1055
Stretching vibration of C-O ester groups
1180
C-O-O vibration of hydroperoxide
990–980
Bending of C-O of ester overlapping with CH bending of trans-double bond
975
975
Bending of C-O of acid
723
723
Overlapping of the CH2 rocking vibration and the out-of-plane vibration of cis-distributed olefins