Abstract: In order to establish optimal conditions for preparing nanoparticles from chitosan (CS) and sulfobutylether-β-cyclodextrin (SBE-β-CD), the effects of different preparation conditions on the particle size, polydispersity index (PDI) and zeta potential of nanoparticles were studied by single factor experiments. The nanoparticles were characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Further, the effects of adding the nanoparticles to sodium alginate film on its mechanical properties (tensile strength, elongation at break) and physical properties (film thickness and water vapor permeability) were investigated. The results showed that the optimum conditions for preparing the nanoparticles were as follows: use of CS with molecular mass of 100 kDa; pH of CS solution, 4.0; CS concentration, 0.75 mg/mL, and mass ratio of CS to SBE-β-CD, 0.8:1. The particle size, PDI and zeta potential of the nanoparticles prepared under the optimized conditions were 245.1 nm, 0.068, and +30.2 mV, respectively. Under TEM, it was observed that the nanoparticles were uniform and regular spheres. FTIR showed that CS was electrostatically combined with SBE-β-CD, leading to enhanced hydrogen bonding. The tensile strength of the composite film with 1.00 mg/mL of CS/SBE-β-CD nanoparticles increased from 18.18 to 29.15 MPa, the elongation at break decreased from 38.91% to 26.42%, and the water vapor permeability rate dropped from 0.36 to 0.21 g·mm/(m2·h·kPa) compared with those of the blank control group. From these results, it was demonstrated that the addition of CS/SBE-β-CD nanoparticles could improve the mechanical and physical properties of sodium alginate film.

Key words: chitosan sulfobutylether-β-cyclodextrin nanoparticles; preparation; characterization; nanoparticle film; mechanical properties; physical properties