Characterization by Fourier transform infrared spectroscopy of polyethylene adipate/cholesteryl palmitate blends

Abstract

FT-IR spectroscopy has been employed to study compatibility, melting, and crystallization of the polyethylene adipate (PEA)/cholesteryl palmitate (CP) blends. The changes in FT-IR spectra were followed by controlled rate of heating and cooling. The bands corresponding to the crystalline structure have been assigned. The accuracy of the transition temperature determination has been improved by fitting the curve of the integral absorbance dependence on temperature with a Boltzmann function. From dependence of the transition temperatures on the composition of the blend, it has been established that for each mixing ratio a certain mass fraction of CP should be dissolved in the PEA matrix. The PEA/CP blends behave as a phase-separated system with partial miscibility.

Characterization by Fourier Transform Infrared Spectroscopy (FT-IR) and 2D IR Correlation Spectroscopy of PAMAM Dendrimer

“…Vibrational frequencies are very sensitive to small changes in the bonding and geometrical arrangement of atoms in molecules. Infrared spectroscopy provides direct and distinct information about the molecular structure, conformation, and orientation of individual segments of LC molecules. , Fourier transform infrared (FT-IR) spectroscopy offers the accessibility to H-bond interactions in these systems, real-time conformational and structural changes during temperature variations, , and orientational behavior. The development of the two-dimensional-2D correlation spectroscopy opened new possibilities in this field.…”

Gelatin Reinforced with CNCs as Nanocomposite Matrix for Trichoderma harzianum KUEN 1585 Spores in Seed Coatings

“…Because the spectrum of the CNC partially overlaps with the spectrum of gelatin, to provide evidence of the interactions taking place in the composites the experimental spectra and their derivatives were compared with the calculated ones (using the components’ spectra and the low additivity) [ 22 ]. For an immiscible blend, the calculated and the experimental spectra should be the same, while for a miscible blend, differences can occur due to the interactions between the components [ 23 ].…”

“…Other important bands in the fingerprint region of the gelatin spectrum are observed at 1447, 1395, 1279, 1197, 1159, 1116, 1081, 1028 and 971 cm −1 . These are assigned to the CH deformation vibration, OH in plane deformation vibration, CH bending vibration, C-N stretching vibration in amine groups, C-O-C stretching vibration, C-C stretching vibration and C-O stretching vibration, respectively [ 23 , 24 , 25 ].…”

“…In addition, the spectrum of CNC shows some characteristic bands at 1458, 1427, 1369, 1337, 1314 and 1275 cm −1 assigned to stretching and deformation vibration of CH groups; at 1203, 1159, 1107 and 1055 cm −1 assigned to stretching and deformation vibration of C–O–C and C-O groups [ 23 ]. As for the previous region, the calculated spectra ( Figure 2 b,d) indicate similar bands to gelatin or CNC, which vary in intensity proportionally with the variation of the concentration of the components.…”

“…Gelatin films present a broad signal at 2θ of 20° assigned to the high content of amorphous faction and to the distance between adjacent polypeptide strands of G [ 33 ] and a small band at 7.7° assigned to triple-helix crystalline structures [ 32 ]. CNC diffractogram presented typical signals of cellulose I, such as: 15.2° signal assigned to the (1–10) plane, 16.4° signal assigned to (110) plane, 20.3° signal corresponding to (102) plane and 22.6° signal assigned to the (200) crystallographic plane [ 23 , 34 ]. The signals from 16.4° 2θ and 20.3° 2θ merged with the ones from 15.3° 2θ and 22.6° 2θ, being almost unnoticeable [ 35 ].…”