In this part, theprepared epoxy of vegetable oils and CaOFA based different polyols structure and functionalities were investigatedby FT-IR. The measurement of FT-IR were carried out in attenuated totalreflectance mode using a thermoset scientific nicolet 6700 spectrometer. IRspectra were obtained at 4 cm-1 resolution between standard wavenumber ranging from 400 to 4000 cm-1.
1 Fig. 1(a) and 1(c) showsthe FT-IR spectra of epoxidised ENO and EJO. The FT-IR spectra reveals that thepresence of epoxy group at 826 cm-1, 824 cm-1 and 843 cm-1respective epoxy oils. Fig. 1(e).
shows, the broad peak between 3600 to 2500 cm-1,which was assigned to overlapped signalfrom the -OH stretching of the hydroxyl and the carboxylic groups of fatty acidCaOFA. The peak at 823 cm-1 was no longer observed for the fattyacids because most of the epoxy groups were reduced during the ring openingstep2-3. Fig 1(b) and 1(d), shows theintensity of epoxy group at 843 cm-1 and 837 cm-1 are disappeared whileCaOFA of fatty acid unit facilitate the ring opening of all the epoxy oils. Thereaction of carboxyl to epoxy group ratio were increased because of which showsthat most of epoxy groups were ring- opened by hydroxylated fatty acid CaOFA.The –OH group is intrinsically present in CaOFA fatty acid recinoliec acidmoiety is shown the fig.
1(e). On the other hand, the NCOL and JCOL polyol of all the –OH groups, the presence of broad peak appeared at 3498 cm-1,3462 cm-1 showsthe -OH group of CaOFA overlapped withall the epoxy vegetable oils.Fourier transformedinfrared spectra of fig. 1(f) and 1(g).
shows, polyurethane TNCP and TJCP polymer are on the oxygen atoms of thecarbonyl (C=O), ether and ester group (C-O-C) and amine functional groups ( C-Nand N-H) absorbed at 1750-1710 cm-1, 1300-1000 cm-1 and1550 – 1500 cm-1,. After the poly condensation reaction the spectraof polyurethane, the C=O stretching have three peaks due to free ornon-hydrogen-bonded C=O peak observed at 1727-1735 cm-1, thedisordered hydrogen- bonded C=O symmetrical stretching at 1718-1721 cm-1and the vibrational stretching frequency observed at 1703-1704 cm-1respectively. On the other hand, it is valuable to mention the N-H group inpolyurethane could develop hard segment to hard segment disorderd Hydrogenbonding with the oxygen of carbonyl groups.
5,12 Such strong -H bonding actsas physical crosslinks leading to restrict the segmental motion of the polymerchain. The observed N-H bending vibrations at 1598 cm-1, C-O-Cstretching absorption band corresponding to linkage between OH and NCO groupsto form urethane bond in the range 1057-1130 cm-1 also providestrong evidence for the formation of polyurethanes. The peaks corresponding tothe absorption of NH, C=O and C-O were observed at 3314 cm-1, 1707cm-1(non-hydrogen bonded), 1643 cm-1 (hydrogen bonded) and 1225cm-1, respectively, which indicate the new synthesized product having urethane(NHCOO)group.