Preparation And Characterization Of Methoxyl Poly(Ethylene Glycol) Grafted Chitosan

This thesis studied the graft reaction between methoxy poly(ethylene glycol) (mPEG) and chitosan, and the properties of Methoxy poly(ethylene glycol) grafted chitosan (CS-g-mPEG). CS-g-mPEG samples with different graft degree were prepared by the reaction of aldehyhyded methoxy poly(ethylene glycol) and 2-amino functions of chitosan. The comb-shaped CS-g-mPEG can be dispersed in water. Their structures and properties were characterized by FTIR, 1H-NMR, XRD, DSC and TG. The rheological properties of CS-g-mPEG were studied by Ubbelohde viscometer. CS-g-mPEG shows different peoperties from chitosan. Sub-microparticles were prepared by CS-g-mPEG and tripolyphosphate through ionize gelation. The diameter and morphology were measured by BI-90Plus particle size analyzer and TEM respectively. The results indicate that all the sub-microparticles present sphere structures with diameters between 100 nm and 800 nm.Methoxy poly(ethylene glycol) methacrylate (mPEGMA) grafted chitosan (CS-g-mPEGMA) were prepared by the reaction of the vivyl groups of mPEGMA with free radicals on chitosan main bones initiated by ceric ammonium nitrate(CAN). The influences of reaction time, reaction temperature, concentration of CAN and mPEGMA on the graft degree and graft efficiency were studied. The structure of CS-g-mPEGMA was characterized by FTIR, and their solution properties were studied. The results indicate that CS-g-mPEGMA can be dispersed in several solvents such as DMF, DMSO, NaOH solution et al.Morever, chitosan-O-methoxy poly(ethylene glycol) (CS-O-mPEG) was obtained by the etherification rection of hydroxyl groups of N-phthaloyl chitosan and diolized methoxyl poly(ethylene glycol) in DMF at the presence of Ag2O. The phthaloyl groups were removed by hydrazine monohydrate to regenerate free amino groups. FTIR showed that mPEG has been grdfted onto the hydroxyl groups of chitosan.