The 1H NMR spectra of chitosan and quaternized chitosan were acquired at 353 K by using a 200-MHz spectrometer (Bruker AC200). For this analysis, samples of CS and HTCC were dissolved in 100:1 D2O–HCl. The parameters for the acquisition of the 1H NMR spectra were as follows: a pulse of 90, corresponding to a pulse width of 8.2 lm; LB 0.55 Hz and 16 transients were acquired.