3.3. ATR-FTIR spectroscopy
Fig. 2 depicts the ATR-FTIR spectra of CS, PBT and CS-g-PBT. As indicated in the spectrum of CS, the broad band around 3340 cm−1 was assigned to NH2 and OH stretching vibration, due to the intra/intermolecular hydrogen bonds of CS molecules. The absorption peak at 1150 cm−1 was the asymmetric stretching of the C O C bond, and the peak at 893 cm−1 resulted from the skeltal vibration of C O stretching. Meanwhile, the peak at 1589 cm−1 was the characteristic peak of primary amine on the deacetylated CS. Regarding the spectrum of PBT, the strong peak located at 1735 cm−1 originated from the stretching vibration of CO on PBT ester group, and the peaks at 2968 cm−1 and 3564 cm−1 were attributed to the stretching vibration of CH2 and OH on the PBT chain. Obviously, the characteristic peaks of CS and Fig