Preparation And Atibacterial Properties Of Bacterial Cellulose Silver-loaded Material

With the lack of global energy,humans are paying more and more attention to renewable energy.Cellulose is one of the main components of biomass.As an important renewable resource,it accounts for 35-50%of biomass.Due to its richness and environmental protection,renewability,biocompatibility and biodegradability,it is a good substitute to replace petroleum-based polymers.Bacterial cellulose,as a kind of cellulose,has advantages such as high purity and nanostructure compared with plant cellulose,so it is widely used in medicine,food,papermaking,electronics and other fields.This paper mainly uses bacterial cellulose as the substrate and raw material.The bacterial cellulose was silver plated by in-situ synthesis.Through characterization,and explore its bactericidal properties.At the same time,a variety of bacterial cellulose silver-loading methods were proposed,which gave the material more functions.A new procedure for the determination of silver(Ag)in Ag-loaded cellulosic materials was proposed using spectroscopic method.Two calibration models were established based on UV-visible spectroscopy(Model 1)and Ratio spectrum-derivative spectrophotometry(Model 2).The correlation coefficient of Model 1 is 0.9852 when the concentration of silver ions(Ag~+)in AgCl suspension system is less than 1.0mmol/L.By contrast,Model 2 exhibits an extended detection range,from 0 to 1.2mmol/L,and its correlation coefficient is also reached to 0.9941.Reproducibility test shows a standard deviation of 0.8080 for Model 2,it is obviously lower than that of Model 1(1.0744),which explains a better reproducibility was achieved by Model 2.Validation experiment shows the average relative errors for two models,5.15%(Model1)and 2.35%(Model 2)respectively,which indicates that predictability of Model 2 is better than that of Model 1.Compared with traditional methods,the proposed test procedures were simplified,the errors caused by human factors were reduced,and testing time was shortened evidently.The new method has high precision and accuracy,it is satisfactorily applied for the determination of silver in Ag-loaded cellulosic materials.A method for preparing silver-loaded cellulose paper based on seed core formation was proposed as a functional material with high antibacterial properties.In this study,Pd nanoparticles were used as seed nuclei,and Ag was deposited on the Pd seed nuclei.The more environmentally friendly potassium sodium tartrate tetrahydrate instead of sodium borohydride was used to stimulate the Ag deposition reaction.The optimal conditions for preparing the Pd-Ag cellulose paper are:the amount of silver nitrate is30mg,the reaction temperature is 50°C,the redox reaction time is 5 min,and the amount of potassium sodium tartrate tetrahydrate is 200mg.By comparison,the stress,strain,and Young's modulus of the modified bacterial cellulose were increased by81.1%,66.4%,and 9.3%,respectively,compared with the unmodified bacterial cellulose.At the same time,BC and BC-Pd-Ag were tested for E.coli and S.aureus,and the bacteriostatic rings of E.coli and S.aureus of BC-Pd-Ag were 4.86mm and6.52mm,that indicating they have good antibacterial properties.Silver nanowires were prepared by the polyol method.Silver nanowires were prepared using silver nitrate as the silver source,ethylene glycol as the solvent and reducing agent,ferric chloride as the inducer,and PVP as the structure directing agent and protecting agent.The prepared silver nanowires and cellulose were mixed and suction filtered into a conductive paper.When the amount of ferric chloride is 1.5ml,the silver nanowires have a width of 100nm,a length of 20um,and an aspect ratio of200.After calculation,the amount of silver nanowires carried in the prepared cellulose/Ag NWs paper was 4.53%,and the resistance of the cellulose/Ag NWs paper was only0.9 ohms.At the same time,antibacterial experiments showed that the bacteriostatic rings of E.coli and Staphylococcus aureus on conductive paper were 3.7mm and 1.5mm,respectively.Therefore,cellulose/Ag NWs paper not only has a conductive function,but also gives it an antibacterial function.Modified bacterial cellulose membrane(BC)with polydopamine(PDA)as coating.The BC-PDA material was prepared by using the adhesion of polydopamine(PDA).Secondly,the BC-PDA-Ag antibacterial material was prepared by reducing in situ silver nanoparticles with polydopamine.The results show that the bacterial cellulose treated by PDA has 86.24%and 65.07%higher stress-strain performance than pure bacterial cellulose,respectively,while giving stronger UV shielding ability and blocking almost the entire UV region(200-400nm).The bactericidal experiment proved that it has a good bactericidal effect on E.coli and Staphylococcus aureus,and the width of the bacteriostatic ring was 7.62mm and 7.54mm,respectively.The material has good bactericidal effect,high strength and simple preparation process.It can be widely used in the field of bactericidal materials and anti-ultraviolet materials.