Study On Preparation And Antimicrobial Activities Of Novel Benzene/Cyclohexyl Group Derivatives Of Chitosan

In this thesis,chitosan with different molecular weight was used as raw material,three mono-isocyanates and two phenoxycarboxylic acid herbicides were grafted onto chitosan molecules to prepare eight chitosan derivatives containing benzene/cyclohexyl group,and the antimicrobia activity of the derivatives was studied.Then,C_2,6-methanamide-polymer nano chitosan was prepared.Firstly,the high and low molecular weights of C_2,6-cyclohexyl methanamide-chitosan conjugates（CHAMCS）,C_2,6-1-naphthyl methanamide-chitosan conjugates（1NPAMCS）,and C_2,6-4-（trifluoromethyl）phenyl methanamide-chitosan conjugates（4TPAMCS）were prepared,and the high polymer chitosan derivatives were prepared into nano dosage form.Two phenoxy carboxylic acid herbicides were grafted onto low molecular weight chitosan by condensation reaction.Its structure was characterized by FTIR,¹³C NMR,elemental analysis and high resolution transmission electron microscopy.In addition,the optimum synthesis conditions of the reaction were selected by orthogonal experiment.Meanwhile,the antimicrobial properties of ch itosan derivatives were studied,and the antimicrobial rules were also discussed.The antimicrobial activities of eight derivatives against four animal pathogenic bacteria（Sarcina,Staphylococcus aureus,Escherichia coli and Pseudomonas aeruginosa）,one potato pathogenic bacteria（Potato scab）and two plant pathogenic fungi（Fusarium equiseti and Verticillium dahliae）were tested by the zone of inhibition.The results showed that the maximum ZOI of 1NPAMHCS and 4TPANHC against Sarcina was 24mm at the concentration of 400 mg/L.The maximum ZOI of 4TPAMHCS to Potato scab was 27 mm.The ZOI value of CHAMLCS inhibiting Verticillium dahliae was 15 mm.At400 mg/L,the ZOI value of Chipton-Lcs to Sarcina and Potato scab reached 22 mm.The antimicrobial properties of the eight derivatives were significantly higher than that of chitosan materials,which had the potential to further develop environmental protection pesticides.