| As people living standard and awareness of health improving, people pay more attentions todeveloping cotton textiles (especially cotton fabrics) of antibacterial function. At present,finishing technology of cotton fabric with nano-silver has been widely used in the preparation ofantibacterial cotton fabric, but it also exits some disadvantages, for example, low utilization rateof silver ion, poor property of antibacterial and washing resistance, etc. In view of this, accordingto principles of adsorption of silver ions and in-situ of reducing silver ions, some kinds ofprocesses which were used to prepare nano-silver antibacterial finished fabrics were studied,including nano-silver finishing of cotton fabrics by method of reducing silver ions with cottonitself, nano-silver finishing of cotton fabrics by method of reducing silver ions with reductant,nano-silver finishing of grafted cotton fabrics by method of reducing silver ions with reductant,and nano-silver finishing of grafted cotton fabrics by method of silver nitrate dipping and steamreducing. The influences of different processes on silver content on fabrics, utilization rate ofsilver ions, antibacterial property and washing resistance were investigated. A new kind ofnano-silver finishing process with some advantages such as high utilization rate of silver ion, andlow-cost would be developed, and the finished fabrics would have an excellent antibacterialproperty and washing resistance. The study of paper was divided into two parts.Part one: Study on nano-silver finishing of cotton fabrics, including methods of reducingsilver ions with cotton itself and reductant on cotton fabrics. In the process of reducing silverions with cotton itself, the silver ions were reduced into nano-silver by potential aldehyde groupof cotton molecular chain terminal; In the process of reducing silver ions with reductant, thesilver ions were reduced into nano-silver by reductant. The influences of finishing factors of twoprocesses on the silver content on fabrics were studied, two kinds of processes conditions wereoptimized, and, silver content on fabrics, antibacterial property and washing resistance offinished fabrics and utilization rate of silver ions of two finishing processes were tested, Theresults show that the optimum process conditions of the method of reducing silver ions withcotton itself are that dipping temperature is80℃, dipping time is50min, bath ratio is1:50, pH is7, When the concentration of silver nitrate is0.3mM(mmol/L), silver content on fabrics is 134.7mg/kg，the utilization rate of silver ions is8.47%，the bacterial inhibition rate for bacilluscoli and staphylococcus aureus reach99.6%and99.9%respectively, after washing50times, theretention rate of silver on fabrics decreases to70.28%；the optimum process conditions of themethod of reducing silver ions with reductant are that dipping temperature is80℃, dipping timeis30min, the molar ratio of sodium citrate and silver nitrate is10:1, bath ratio is1:50, pH is7,When the concentration of silver nitrate is0.3mM, the silver content on finished fabric is266.5mg/kg，the utilization rate of silver ions is16.71%，the bacterial inhibition rate for thesetwo kinds of bacteria both reach99.9%, after washing50times, the retention rate of silver onfabrics decreases to71.72%. The study indicates that compared with the method of reducingsilver ions with cotton itself, utilization rate of silver nitrate of the method of reducing silver ionswith reductant is higher, the washing durability of finished fabrics has a little improvment. Thismethod can increase utilization rate of silver nitrate effectively, but it has little influence onwashing durability of finished fabrics.Part two: Study on nano-silver finishing of methacrylamide grafted cotton fabrics:. There arethree research sections in this.part(1) Preparation of methacrylamide grafted cotton fabric. The grafted cotton was prepared withMA, MAA as grafting monomers and potassium persulfate (KPS) as initiator. The influences offinishing factors of the process on the grafting ratio were studied, the process conditions wereoptimized, the grafting ratio, hygroscopicity and whiteness of finished fabrics were tested. Theresults show that the optimum process conditions are that KPS concentration is0.3mol/L,reaction temperature is70℃，reaction time is90min，pH is9, bath ratio is1:30. The graftingratio of fabrics increases with improvment of MAA concentration, and when MAA concentrationis0.6mol/L, grafting ratio of finished fabrics reaches balance, it’s22.94%. Hygroscopicity offinished fabrics increases with improvment of grafting ratio, but grafting has little effect onwhiteness of finished fabrics.(2) Study on nano-silver finishing of methacrylamide grafted cotton fabrics by the method ofreducing silver ions with reductant. The influences of finishing factors of the process on silvercontent of fabric were studied, the process conditions were optimized, the silver content onfabrics, antibacterial property and washing resistance of finished fabrics and utilization rate ofsilver ions of process were tested, this process was further compared with finishing process of cotton fabrics by reducing silver ions with reductant. The results show that the optimum processconditions are that grafting ratio is15.05%，molar ratio of sodium citrate and silver nitrate is5:1,dipping temperature is90℃, dipping time is40min, pH is7, bath ratio is1:50. When theconcentration of silver nitrate is0.3mM, the silver content on finished fabrics is575.3mg/kg，theutilization rate of silver ions is35.51%，the bacterial inhibition rate for bacillus coli andstaphylococcus aureus both reach99.9%, after washing50times, the retention rate of silver onfabrics is75.23%, the bacterial inhibition rate for these two kinds of bacteria also maintain99.9%. The study indicates the process of methacrylamide grafting onto cotton fabrics canincrease observably utilization rate of silver ion, meanwhile, washing resistance of finishedgrafted fabrics also increases in a certain extent.(3) Study on nano-silver finishing of cotton fabrics grafted methacrylamide by silver nitratedipping and steam finishing. The influences of finishing factors of the process on silver contentof fabric were studied, the process conditions were optimized, the silver content on fabrics,antibacterial property and washing resistance of finished fabrics and utilization rate of silver ionsof process were tested, this process was further compared with finishing process of graftedcotton fabrics by reducing silver ions with reductant. The results show that the optimum processconditions are that grafting ratio is15.05%, pH is7, dipping time is30min, steaming time is30min, When the concentration of silver nitrate is0.1mM, the silver content on finished fabricsis102.9mg/kg，the utilization rate of silver ions is20.19%，the bacterial inhibition rate forbacillus coli and staphylococcus aureus both reaches99.9%, after washing50times, theretention rate of silver on fabric is85.19%, the bacterial inhibition rate for these two kinds ofbacteria are over97%. The study indicates that compared to finishing process of grafted cottonfinished by reducing silver ions with reductant, the utilization rate of silver ions of this process islower, but washing resistance of finished fabrics has a great improvment. Cooperation ofadsorption and reduction of finishing process of grafted cotton fabrics by reducing silver ionswith reductant enhances adsorption rate of silver ions.The results of research indicate that for improving utilization rate of silver ions, thefinishing process of cotton fabrics grafted methacrylamide by reducing silver ions with reductantis optimum process; for improving washing resistance of finished fabrics, the finishing processof cotton fabrics grafted methacrylamide by silver nitrate dipping and steam finishing is optimum process; but considering that steps of silver ions adsorbing and reducing are divided inthe finishing process of methacrylamide grafted cotton fabrics by silver nitrate dipping andsteam finishing, it’s in favor of recycle of silver ions dipping liquids and improvement ofutilization rate of silver ions in the production process, which will reduce production cost.Therefore, the finishing process which includes methacrylamide grafting onto cotton fabrics,silver nitrate dipping and steam finishing is an ideal nano-silver antibacterial finishing process. |
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