Preparation And Performance Study Of Non-cyclic Haloamine Antibacterial Mesoporous Silica And Antibacterial Hydrogel

In recent years,with the continuous improvement of people's living standards,people have gradually paid attention to various external factors that harm their own health.In daily life,there are widespread and extensive distribution of various bacteria and viruses in the nature,which threaten people's health and even life safety,more likely to endanger the harmony and stability of society and the sustainable development of economy.Therefore,it is of great significance to study new environmental protection and healthy antibacterial materials to safeguard people's daily life.N-halamine antibacterial materials have attracted wide interest from researchers due to their excellent antibacterial efficacy,broad-spectrum antimicrobial activity,and the reproducibility of antibacterial functional groups.However,there are not too much study on acyclic N-halamine antibacterial materials at home and abroad.Therefore,this thesis focuses on the study of acyclic N-halamine antibacterial materials.In this thesis,we have successfully prepared an antibacterial mesoporous silica containing acyclic N-halamine functional groups and an antibacterial hydrogel containing acyclic N-halamine functional groups.?1?Study on the preparation and properties of antibacterial mesoporous silica containing acyclic N-halamineIn polyvinyl alcohol?PVA?solution,sodium carbonate was used as catalyst to react with?,?-unsaturated amide group of methylene-bis-acrylamide?MBA?via hydroxyl group on PVA molecular chain to obtain a polymer?PVA-MBA?containing acyclic N-halamine precursor functional group.After water glass was added to PVA-MBA solution,mesoporous silica?PVA-MBA@SiO₂?containing acyclic N-halamine precursor functional group could be obtained by adjusting the pH of the mixed solution.After a simple chlorination in NaOCl solution,antibacterial mesoporous silica containing acyclic N-halamine?PVA-MBA-Cl@SiO₂?particles were formed via converting the amide groups in PVA-MBA@SiO₂ particles into N-halamine ones.The chemical structure and morphology of the as-prepared PVA-MBA-Cl@SiO₂ particles were characterized by transmission electron microscope?TEM?,Fourier-transform infrared spectroscopy?FT-IR?,X-ray photoelectron spectroscopy?XPS?,X-ray diffraction?XRD?,and Brunauer-Emmet-Teller?BET?analyses.BET analysis and oxidative chlorine content test showed that the specific surface area of the prepared PVA-MBA-Cl@SiO₂ and the oxidation chlorine content?Cl⁺%?could reach up to 380m²/g and 3.87%,respectively.The antibacterial efficacy test showed that the as-prepared PVA-MBA-Cl@SiO₂ particles have very strong bactericidal ability and could completely kill 2.1×10⁶ CFU/mL of Staphylococcus aureus and 5.6×10⁶ CFU/mL of Escherichia coli within 10 min.The regenerative performance test showed that the N-halamine antimicrobial functional groups in PVA-MBA-Cl@SiO₂ have very good regenerability and after 10 regeneration cycles,the Cl⁺%in PVA-MBA-Cl@SiO₂ was still 3.55%.The storage stability showed that the PVA-MBA-Cl@SiO₂ prepared after storage at room temperature for 6 weeks,its Cl⁺%decreased only from 3.84%to 3.69%,indicating that the N-halamine functional groups on the prepared PVA-MBA-Cl@SiO₂particles have very good storage stability.?2?Study on the preparation and properties of antibacterial hydrogel containing acyclic N-halamineWith polyvinyl alcohol?PVA?as the polymeric skeleton,a polymer containing acyclic N-halamine precursor functional groups?PVA-MBA?was obtained via grafting reaction between the active hydroxyl groups on PVA and?,?-unsaturated amide groups of methylene-bis-acrylamide?MBA?under the catalysis of sodium carbonate in aqueous solution.With a freeze-thaw cycle method,the PVA-MBA hydrogel could be obtained from the as-prepared PVA-MBA solution.Then,chlorinating the amide group on the PVA-MBA hydrogel could produce an antibacterial hydrogel PVA-MBA-Cl containing acyclic N-halamine functional groups.We have tested the mechanical properties of the hydrogel and the content of oxidized chlorine,and used FE-SEM to characterize the internal structure of the prepared materials.The antibacterial efficacy test showed that the prepared PVA-MBA-Cl hydrogel with an Cl⁺%of 2.92%could kill1.0×10⁶ CFU/mL of Staphylococcus aureus and 2.3×10⁶ CFU/mL of Escherichia coli within 10 min.In addition,we also performed a preliminary evaluation of the storage stability of the N-halamine functional groups in the prepared PVA-MBA-Cl hydrogel.