Studies On Preparing And Immobilizing Of Quaternary Polyethyleneimine And Its Antimicrobial And Corrosion Inhibition Property

Quaternary Polyethyleneimine (QPEI) was prepared via two procedures of polymer reactions, tertiary amination and quaterisation, and the effects of various reaction conditions on the reactions were examined. The chemical structures of the products were characterized with UV and FTIR spectra. Through comparing experiments, the cationic character of QPEI was researched. The study results show that the tertiary amination for primary and secondary amine groups on macromolecular chains of PEI can realized greenly, the tertiary amination is an exothermic reaction, the enhance of temperature will make tertiary amine degree decreased, so the reaction needs to be performed at low temperature (at 3℃). Using benzyl chloride as quaternary reagent, more than 90% of tertiary amine groups can be quaternarized for 30h at 50℃, so that the quaternary degree of the total N atoms on PEI macromolecular chains come up to 50%.The antimicrobial property of this polymeric quaternary ammonium salt was mainly researched using Escherichia Coli as a disease-leading bacterium. The effects of quaternary degree and pH value on the antimicrobial property were examined with the method of plate counting live bacterium, and the antimicrobial mechanism of QPEI was studied more deeply via measuring the activities ofβ-D-galactosidase and TTC-dehydrogenase. The experiment results indicates that QPEI possesses very strong antimicrobial ability, and the antimicrobial ratio reaches 100% when contacting with bacterium suspension of 109CFU/mL under the conditions of contacting time of 4 min and a dose of 15mg/L. The cationic degree influences QPEI antimicrobial property to a greet extent, and the higher the cationic degree is, the better the antimicrobial activity. In a certain region of pH value, the higher the pH, the stronger antimicrobial ability is. The results of measuring activities of two enzymes,β-D-galactosidase and TTC-dehydrogenase, show that the antimicrobial mechanism of QPEI is based on a sterilizing bacterium process, and not only is based a restraining action.The corrosion inhibition property and mechanism of QPEI for low carbon steel which was dipped in aqueous solution of H2SO4 of 0.5mol/L were investigated by using weight-loss method, electrochemical polarization measurement and scanning electron microscope method. The experiment results show that QPEI possesses excellent corrosion inhibition property, and only under the concentration condition of 5mg/L, the corrosion inhibition rate comes up to 91% for A3 steel sample which is dipped in sulfuric acid medium of 0.5mol/L for 72h. QPEI can restrain simultaneously cathode process and anode process, so its corrosion inhibition belongs to the mixed type. With the synergistic action of adsorption film formation and polymer film formation, QPEI can produce compact and dense film on the surface of steel, and QPEI has double functions of the inhibitor of adsorption type and the inhibitor of film forming type. the adsorption behaviour of QPEI on the surface of low carbon steel fits to Langmuir equation.Polyethyleneimine was grafted on silica gel(PEI/SiO2) by usingγ-chloropropyl trimethoxysilane(CP-TMS) as coupling agent. And then PEI on silica gel was quaternized using epihydrin as the tertiary amination agent and benzyl chloride as the quaternary reagent. Finally the water-insoluble antibacterial material(QPEI/SiO2) was obtained. The chemical structures of the products were characterized with FTIR spectra. The antibacterial character and mechanism of QPEI/SiO2 was researched. The effects of quaternary degree on the antimicrobial property of QPEI/SiO2 were examined. The experiment results indicates that QPEI/SiO2 also have very strong antimicrobial ability. The antimicrobial ratio is close to 100% when contacting with bacterium suspension of 109CFU/mL under the conditions of a dose of 15g/L and contacting time of 10 min. The higher the cationic degree is, the better the antimicrobial activity. The results of measuring activities of two enzymes,β-D-galactosidase and TTC-dehydrogenase show that the antimicrobial mechanism of QPEI/SiO2 is also the same as QPEI, and it is also based on a sterilizing bacterium process. Insoluble macromolecular antibacterial material has more higher antibacterial activity relative to smaller molecular antibacterial owing to higher density of antibacterial groups on molecular chain. Furthermore, this insoluble antibacterial material protects the water from being polluted the second time due to macromolecular antibacterial immobilized on the insoluble carriers.