Methoxy poly(ethylene glycol)/chitosan graft co-polymers (CS-g-mPEGs) with different
degrees of substitution were synthesized by reductive N-alkylation of chitosan with poly(ethylene
glycol) aldehyde. The crystalline and thermal properties of CS-g-mPEGs were characterized by
wide-angle X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetry
(TG). The results indicate that CS-g-mPEG solids represent microphase separation morphology with
mPEG crystal and CS domains coexistence and the introduction of PEG on CS improves the thermal
decomposition. The hydrodynamic behavior of CS-g-mPEGs in aqueous solution and the influence
of NaCl were investigated. The results indicate that the hydrodynamic behavior of CS-g-mPEGs in
aqueous solution is significantly affected by the degree of substitution and the concentration of NaCl,
which are quite different from that of CS. The results of this paper also certify that CS-g-mPEGs
keep the property of complexation with a counter-ion, such as tripolyphosphate, to form nanoparticles
through the electrostatic interaction.