“…At 1470 and 1370 cm −1 , bands of moderate intensity were identified related to the axial deformation of aliphatic C-H groups and a 721 cm −1 out-ofplane CH deformation [18]. A PCL-0 sample showed the following typical polycaprolactone bands: a band in the range of 3637 to 3326 cm −1 , which can be attributed to the vibration of stretching and deformation of the hydroxyl groups (O-H) as a function of water absorption and coordination with the water [37]; at 2942 cm −1 , which can be referred to as the asymmetric stretching of the -CH2 group; at 2868 cm −1 , related to the symmetric stretching of the -CH2 A PCL-0 sample showed the following typical polycaprolactone bands: a band in the range of 3637 to 3326 cm −1 , which can be attributed to the vibration of stretching and deformation of the hydroxyl groups (O-H) as a function of water absorption and coordination with the water [37]; at 2942 cm −1 , which can be referred to as the asymmetric stretching of the -CH 2 group; at 2868 cm −1 , related to the symmetric stretching of the -CH 2 group; at 1726 cm −1 , due to the presence of the carbonyl ester group (C=O), with consequent stretching vibration of -CO [38]; at 1474 cm −1 , due to C-H vibration; at 1298 cm −1 , due to C-C and C-O stretching; at 1169 cm −1 , attributed to the asymmetric stretching of the C-O-C bond; and at 1040 cm −1 , due to C-O-C stretching vibration [39]. For sodium alginate (powder), bands were identified at 3378 cm −1 , representing the stretching vibration of the hydroxyl group O-H; at 2929 cm −1 , attributed to the symmetric stretching mode for CH 2 [40]; at 1610 cm −1 , referring to the COO-asymmetric stretch; at 1413 cm −1 , attributed to the C-OH group; at 1121 cm −1 , typical of the vibrations of the C-O/C-C groups; at 1087 cm −1 , related to the C-O-C cluster; and at 1026 cm −1 and 944 cm −1 , referring to the stretching of the C-O group, related to the residual mannuronic and guluronic acids in the composition of the alginate [41,42].…”