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

Author:Wang Ying Zuo

Supervisor:ren xue hong


Degree Year:2019





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.