4.4. FTIR characterization
The FTIR spectra of chitin flakes, chitin NFs and chitosan NPs and chitosan NFs mixture are shown in Fig. 5. FTIR spectra for chitin flakes and chitin NFs are in accordance with the previously published work (Cárdenas et al., 2004, Ifuku et al., 2009 and Ifuku et al., 2011). The broad and weak absorption bands from 3600 cm−1 to 3000 cm−1 are due to the combined absorption by Nsingle bondH and Osingle bondH groups in the chitin polymer (Fig. 5(a) and (b)). The absorption band at 3253 cm−1 in chitin flakes and 3458 cm−1 in chitin NFs can be attributed to the Nsingle bondH secondary amine stretch. The absorption band due to the presence of NHsingle bondCO group in the chitin structure is located at 3101 cm−1. The weak absorption band in the region of 2961–2829 cm−1 is due to the presence of methylene and methyl groups in the chitin structure and originates due to the C—H bond of sp3 hybridized carbon. The spectra also show the presence of two bands in the region of 1660–1620 cm−1. Both these bands are due to the Cdouble bond; length as m-dashO stretching vibration of the amide I bonds. Splitting of the peak in to two characteristic bands at 1655 cm−1 and ∼1620 cm−1 is due to the influence of hydrogen bonding in the polymeric structure. The absorption peak at ∼1553 cm−1 is due to the presence of Nsingle bondH of Amide II bond structure in the polymer. Bond absorptions in the region of 1420–700 cm−1 are due to a number of chemical functionalities in the pyranose ring including single bondCHx, single bondCsingle bondOsingle bondCsingle bond and single bondOH.
4.4 การ FTIR จำแนกThe FTIR spectra of chitin flakes, chitin NFs and chitosan NPs and chitosan NFs mixture are shown in Fig. 5. FTIR spectra for chitin flakes and chitin NFs are in accordance with the previously published work (Cárdenas et al., 2004, Ifuku et al., 2009 and Ifuku et al., 2011). The broad and weak absorption bands from 3600 cm−1 to 3000 cm−1 are due to the combined absorption by Nsingle bondH and Osingle bondH groups in the chitin polymer (Fig. 5(a) and (b)). The absorption band at 3253 cm−1 in chitin flakes and 3458 cm−1 in chitin NFs can be attributed to the Nsingle bondH secondary amine stretch. The absorption band due to the presence of NHsingle bondCO group in the chitin structure is located at 3101 cm−1. The weak absorption band in the region of 2961–2829 cm−1 is due to the presence of methylene and methyl groups in the chitin structure and originates due to the C—H bond of sp3 hybridized carbon. The spectra also show the presence of two bands in the region of 1660–1620 cm−1. Both these bands are due to the Cdouble bond; length as m-dashO stretching vibration of the amide I bonds. Splitting of the peak in to two characteristic bands at 1655 cm−1 and ∼1620 cm−1 is due to the influence of hydrogen bonding in the polymeric structure. The absorption peak at ∼1553 cm−1 is due to the presence of Nsingle bondH of Amide II bond structure in the polymer. Bond absorptions in the region of 1420–700 cm−1 are due to a number of chemical functionalities in the pyranose ring including single bondCHx, single bondCsingle bondOsingle bondCsingle bond and single bondOH.
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