Table 4.
Evaluation of the FTIR spectrum for all sample
| Spectral region | Responsible groups |
|---|---|
| 3,444 cm−1 | Overtone of the glyceride ester carbonyl absorption [30] |
| 3,006 cm−1 | C–H stretching vibration of cis-double bond (=CH) [31, 32] |
| 2,925 cm−1, 2,854 cm−1 | Asymmetric and symmetric stretching vibration of the aliphatic CH2 functional group [33] |
| 2,962 cm−1, 2,872 cm−1 | Symmetric and asymmetric stretching vibration shoulder of the aliphatic CH3 group [32] |
| 1,743 cm−1 | Ester carbonyl functional group of the glycerides [31, 32] |
| 1,654 cm−1 | C=C stretching vibration cis-olefins [32] |
| 1,458 cm−1 | Bending vibrations of the CH2 and CH3 aliphatic groups [31] |
| 1,397 cm−1 | Bending in plane vibration of CH cis-olefin groups[31, 32] |
| 1,373 cm−1 | Bending vibration of CH2 groups [31, 32] |
| 1,238 cm−1, 1,163 cm−1 | Stretching vibration of C–O ester groups[32] |
| 717 cm−1 | Overlapping of CH2 rocking vibration and the out-of-plane vibration of cis-disubstituted olefins [31] |