Study On The Preparation And Antimicrobial Properties Of Polyethyleneimine-based Halogenamine Antimicrobial Cellulose Membrane

As the increasing threat of microorganisms on environment and human health,the preparation and application of antibacterial materials have achieved extensive attention.Various antibacterial agents,including nanoparticles of noble metals and metal oxides,quaternary ammonium compounds,chitosanand N-halamines are widely used over the years.Among them,N-halamines have demonstrated many advantages such as rapid inactivation against a broad spectrum of microorganisms in brief contact times,safety to humans and environment,regenerability as well as low cost.In the present study,the regenerated cellulose membrane used as a based material,the N-halamine precursor PEI-DCM was obtained by the selective oxidation of sodium periodate and PEI-grafting.Then the PEI-DCM was immersed in a NaClO solution to obtain a novel antibacterial cellulose membrane?Cl-PEI-DCM?.The appropriate conditions affecting the aldehyde content of DCM and the active chlorine?Cl⁺?content of Cl-PEI-DCM were systematically investigated at the oxidation,grafting and chlorination stages.By using SEM,ATR-FTIR,XRD,XPS,light transmittance measurements and tensile tests,the physical morphologies,crystal structure,surface functional groups,element composition,transparency and mechanical strength of the samples obtained in different stages were characterized.Results showed that the hydroxyl groups on the cellulose membrane?CM?were changed to aldehyde groups and PEI was grafted to the surface of oxidized cellulose membrane by Schiff-base reaction.The N-H bonds were transformed into N-Cl bonds after chlorination treatment.Moreover,the Cl-PEI-DCM displayed good stability,rechargeability,transparency and high mechanical strength.The antibacterial properties of Cl-PEI-DCM were studied by inhibition zone method and modified AATCC Test Method 100-1999.Results showed that Cl-PEI-DCM had high antibacterial efficacy against S.aureus and Gram negative bacteria E.coli.After 15 days of storage,1.30wt%Cl-PEI-DCM can completely inactivate both bacteria species within 5min.When shortening the contact time from 5 to 1 min,it still provided higher than 99.50%reduction for S.aureus and for E.coli after 30 d of storage.By comparison,the PEI-DCM had low reduction of bacteria concentration,which only provided 36.00%reduction of S.aureus and21.40%of E.coli within 30 min,respectively.On the basis of the results obtained in the preparation of Cl-PEI-DCM,another novel antibacterial cellulose membrane?I-PEI-DCM?was prepation via investigating the influence of the aldehyde content of DCM,PEI concentrations and iodine-loading conditions.The Samples before and after iodine-loaded were characterized by SEM,XPS,Raman,ATR-FTIR and XRD.The results showed that demonstrated that the iodine loaded on the I-PEI-DCM surface was the mixture of I₃^-and I₅^-.During the iodination treatment,the the amino groups of PEI molecular chains participated in the complex reaction with polyiodide ions.The microbiological tests showed that the I-PEI-DCM had excellent antibacterial activity against both S.aureus and E.coli.A clear zone of 38 and 31mm diameters was observed around the I-PEI-DCM in the plate.When the contact time was1min,the I-PEI-DCM can completely inactivate all of two bacterial.In addition,I-PEI-DCM displayed good stability and rechargeability.About 92 wt%of the initial iodine loading was still retained after 21 d of storage.After three dechlorination/chlorination cycles,more than 93%of the initial iodine content can be recovered.