Preparation and Application of N-halamine Modified SBA-15 and Coated Cotton

Author:Wang Ying Zuo

Supervisor:ren xue hong

Database:Doctor

Degree Year:2019

Download:43

Pages:104

Size:5798K

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Textile is one of most important materials in human life.Functional modification of textile to increase additional value and expand applications has been the research hotspot in recent years.In this thesis,N-halamines compounds are used for the surface modification of mesoporous silica materials.The N-halamine modified mesoporous materials were characterized and the properties of the materials were investigated.One of N-halamine modified mesoporous materials was chosen to modify cotton by coating process.The antimicrobial and hemostasis properties of cotton coated with N-halamine modified mesoporous materials were tested.In order to expand the application of N-halamine modified mesoporous materials,the reaction mechanism of phenols and ammonia with N-halamines were investigated.The N-halamines modified mesoporous materials could be used in environmental protection and detoxification.Firstly,N-halamine precursor poly[5,5-Dimethyl-3-(3’-triethoxysilylpropyl)hydantoin](PSPH)was synthesized from hydantoin and chloropropyl triethoxysilane,and used to chemically modify the surface of mesoporous materials(SBA-15).The modified mesoporous materials were characterized by X-ray diffraction(XRD),transmission electron microscope(TEM)and Brunauer-Emmett-Teller(BET)analysis,and the structure of modified mesoporous materials was not affected by the modification.After chlorination,SBA-15-PSPH-Cl showed excellent antibacterial property,and inactivated 100%of S.aureus and E.coli O157:H7 with 8.05 and 7.92 log reductions within 1 min of contact,respectively.However,the surface area and pore volume of the modified mesoporous materials were reduced sharply after modification,and only 8%of surface area and pore volume of the modified mesoporous materials was retained.In order to improve the retention rate of surface area and pore volume of the modified mesoporous materials,3-(trimethoxysilyl)propyl methacrylate was used to modify mesoporous materials first,then N-halamine monomers(APDMH)were grafted on the surface of modified mesoporous materials.The retention rate of surface area and pore volume of SBA-15-PAPDMH was much higher than that of SBA-15-PSPH,and could reach 60%.After chlorination,SBA-15-PAPDMH-Cl exhibited excellent antibacterial activity and could inactivate 7.00 and 6.70 logs of E.coli O157:H7(ATCC 43895)and S.aureus(ATCC 6538),respectively,within 5 min of contact.The antibacterial property of SBA-15-PAPDMH-Cl was lower than that of SBA-15-PSPH-Cl due to lower chlorine content.Due to the disorder polymerized of N-halamine monomers,the retention rate of surface area and pore volume of SBA-15-PAPDMH were not consistent.Reversible addition-fragmentation chain transfer polyermization(RAFT)method was used to improve the modification of mesoporous materials,which could form ordered polymer brush on the surface of mesoporous materials.Even though SBA-15-PAPDMAC showed lower retention rate of surface area and pore volume than that of SBA-15-PAPDMH,the reaction process was more controllable and environmental-freindly.After chlorination,the chlorine content of SBA-15-PAPTMAC-Cl was 1.62 wt%.The chlorinated samples showed excellent antimicrobial properties and could inactivate 100%of S.aureus(ATCC 6538)(7.63log)and E.coli O157:H7(ATCC 43895)(7.52 log)within 10 min.Due to the quaternary ammonium groups in SBA-15-PAPTMAC,the unchlorinated sample also showed antibacterial property against S.aureus and E.coli O157:H7.SBA-15-PSPH was chosen to modify the surface of cotton.After chlorination,the coated cotton got the antimicrobial and hemostasis property simultaneously.The hemostasis property and the bioactivity of N-halamine modified mesoporous materials coated cotton were improved.Cotton/SBA-15-PSPH-Cl(Cl~+=0.35 wt%)could completely inactivate 100%S.aureus within 10 min,and 99.99%E.coli O157:H7 within 30 min.One kind of cyclic N-halamine compounds MCDMH was used to react with phenols first,and the reaction mechanism was investigated.MCDMH could react with phenols in aqueous solution efficiency and quickly.SBA-15-PSPH-Cl was chosen to react with phenols in aqueous solution.Phenols can not react with SBA-15-PSPH-Cl in aqueous solution,unless the pH value of solution was above 10.The reaction kinetics was studied,and the reaction was regarded as a pseudo first order reaction to the concentration of phenolic compounds.The reaction could complete within 10 min.However,cotton/SBA-15-PSPH-Cl showed no reactivity with phenols in aqueous solution.The reaction mechanism of ammonia and N-halamine modified mesoporous materials was investigated.MC and MCDMH were chosen to react with ammonia in aqueous solution first,and found that the reaction could finish within a few minutes.No monochloramine was detected after the reaction.Due to the oxidation of N-halamine compounds,ammonia was coverted into nitrogen gas and nitrate after the reaction.The reaction between SBA-15-PSPH-Cl and ammonia in aqueous solution was fast,but monochloramine became the major products.The gas test of SBA-15-PSPH-Cl with ammonia was carried out,and found that water molecule was the key factor in the reaction.Cotton/SBA-15-PSPH-Cl showed good ammonia degradation in aqueous solution,and about 60%ammonia was degraded upon the contact.