Preparation And Properties Of Antibacterial Cellulose Composite Aerogel

In recent years,due to the enormous threat bacteria posing to human health,research on antibacterial materials has attracted extensive attention.Despite great advances in public health and healthcare,bacteria still cause widespread socioeconomic problems.This paper mainly uses cellulose as raw material to prepare antibacterial aerogel composite materials,aiming to apply this new antibacterial material to the fields of medical biology,packaging materials and antibacterial fabrics.Nanocellulose is the most abundant natural polymer compound on earth.It has many excellent physical and chemical properties,such as low density(about 1.6 g/cm~3),high specific surface area(>100 m~2/g),biodegradable and renewable advantages,so it belongs to green biomass resources.Nanocellulose is widely used in hydrogels,aerogels,biomedicine,optoelectronic materials,and other fields,so it is a bio-based material with great research value.In our work,two kinds of cellulose antibacterial aerogel composites were prepared by using cellulose nanofibrils(CNF)and carboxylated fiber nanofibrils(TOCNF)as raw materials,respectively.The prepared aerogel material has the advantages of three-dimensional porous network structure,high porosity,low density,high specific surface area.Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction analysis(XRD),energy dispersive analysis(EDS),thermogravimetric analysis(TGA),pore size analysis(BET),mechanical properties test,degradation performance analysis,antibacterial performance test and biocompatibility test and other means to analyze its structure,morphology and performance.In this experiment,silver nitrate was used as raw material,potassium persulfate was used as oxidant,and the nano-divalent silver oxide(Ag O)was prepared by liquid-phase precipitation method.The particle size distribution of Ag O obtained under the optimal preparation parameters was 10-20 nm.Then,Ag O was used as an antibacterial agent and CNF composite aerogel was used as a carrier.During the blending process,Ag O could have hydrogen bonds and electrostatic adsorption with hydroxyl groups.At the same time,cellulose antibacterial aerogels were prepared by freeze-thaw cycles and freeze-drying methods.The microscopic morphology,mechanical properties,in vitro release of silver ions,antibacterial properties and biodegradability of the composite aerogels were investigated.The porosity of cellulose antibacterial aerogels can reach 94%,the swelling rate was more than 1000%,and the pore size was between 13-15 nm.The aerogels had large storage space and attachment sites.The diameter of the inhibition zone of the composite aerogel for Escherichia coli and Staphylococcus aureus was 23 mm and 20mm respectively,the inhibition rate for Escherichia coli and Staphylococcus aureus was over 99.5%,and it had efficient antibacterial properties.The experiment proposed an economical and novel preparation method of antibacterial cellulose aerogel,making it a more efficient,more antibacterial,and more suitable antibacterial material for daily needs.Citric acid was used as the cross-linking agent,and the TOCNF/ε-Poly-L-lysine(ε-PL)cross-linked network was used as the matrix.A biodegradable and antibacterial multifunctional aerogel material was designed.CA can not only act as a multifunctional crosslinking agent for esterification and crosslinking with TOCNF and hydrogen bond crosslinking with TOCNF andε-PL,but also as a reinforcing agent to improve the mechanical properties and antibacterial properties of composite aerogels.When the content ofε-PL was 0.8 wt%,the inhibition zone diameters of cellulose composite aerogel against Escherichia coli and Staphylococcus aureus were 35 mm and 33 mm,respectively.The composite aerogel had a significant inhibitory effect on Escherichia coli and Staphylococcus aureus,and the antibacterial efficiency was as high as 99.6%.After28 days,the cellulose aerogel was biodegradable in soil.More importantly,the hemolysis rate of the aerogel was less than 5%,and the prepared degradable cellulose aerogel was a material with good blood compatibility,which had great application potential in medical environment and packaging materials.