Reasearch On Antibacterial Finishing Processes Of Cotton Fabric With The In-situ Growthed Nano-silver

In recent years, because of nano-silver with strong antibacterial activity andbroad-spectrum antibacterial, it was widely used in the preparation of antibacterial cotton fabric.But at present there were some disadvantages in antibacterial finishing with nano-silver, such asaggregation of nano-silver and the large particle size of nano-silver, etc. In order to solve theabove problems, in this paper, according to principles of silver ions being complexed andadsorbed and being reduction with amine groups double bond, two finishing processes whichbeing used to prepare nano-silver antibacterial finished cotton fabrics were studied, includingnano-silver finishing of maleic acid modified methyl acrylamide grafted cotton fabric by themethod of silver nitrate dipping and steam reducing and nano-silver finishing of cotton fabricsby method of maleic anhydride modified hyperbranched polymers as template. The influences ofthe two finishing technology of preparing antibactieral cotton fabric on aggregation and particlesize of nano-silver on the finishing fabric prepared were studied, the effect of the two finishingtechnology of preparing antibactieral cotton fabric on antibacterial properties and the physicaland mechanical properties of the finished fabric were investigated, and a new kind of nano-silverfinishing process with some advantages such as without aggregation, small particle size anduniform distribute, and having no effect on the physical and mechanical properties ofantibacterial finished cotton fabric were developped.The study of paper was divided into two parts.Part one：Study on nano-silver antibacterial finishing of methylacrylamide grafted cottonfabric modified with maleic anhydride. Maleic anhydride were used to modify methylacrylamidegrafted cotton fabric to make the branches of polymethacrylamide crosslinked and form anetwork structure, and the process of silver ions for being adsorbed by dipping and for beingreduced by steaming were used to prepare nano-silver fabric.The influences of the factors ofmaleic anhydride modifying process on the UV adsorption rate of the grafted fabic modified withmaleic anhydride were studied, the modifying conditions were optimized, and the structure ofgrafted fabic modified with maleic anhydride was characterized by FT-IR. The influence of finishing factors on silver content on the finished fabric were studied, the process conditions offinishing were optimized, the silver content on fabrics, antibacterial property and washingresistance of finished fabrics were tested. The fiber surface of the finished fabric was observedby SEM, the physical and mechanical properties were measured. The results show that theoptimum modification process condition of the methylacrylamide grafted cotton fabric beingmodified with maleic anhydride were that baking temperature was160℃, baking time was7min,the analysis of FT-IR proved that the amino of polymethacrylamide had being reacted withmaleic anhydride, the aim of maleic anhydride modifing methylacrylamide grafted cotton fabriccame true. The optimum process conditions of nano-silver finishing were that dipping time was30min, steaming time was45min, When the concentration of silver nitrate is0.1mmol/L, thebacterial inhibition rate for bacillus coli and staphylococcus aureus of the finished fabric bothreached99.9%, and after being washed50times, the bacterial inhibition rate for these two kindsof bacteria of the finished fabric were over97%. Compared with unmodified methylacrylamidegrafted cotton fabric, this finishing process can effectively reduce the aggregation of nano-silver,and the particle size of nano-silver of the finished fabric was small, but the tear strength,breaking strength and softness of the finished fabric were decline. The study indicated that themethylacrylamide grafted cotton fabric modified with maleic anhydride nano-silver finishing bythe method of silver ions for being adsorbed by dipping and for being reduced by steaming couldeffectively reduce the aggregation of nano-silver, but the physical and mechanical properties ofthe finished fabric were decline.Part two： Synthesis of maleic anhydride modified hyperbranched polymer and itsapplication in the finishing of cotton fabric with nano-silver.（1）Study on the synthesis and application of modified hyperbranched polymer. A modifiedhyperbranched polymer was synthesized with diethylenetriamine and methyl acrylate as rawmaterials, maleic anhydride as modifier, and applied as template for preparing nano-silver sol.The influence of the dosage of modifier on the particle size of nano-silver was investigated, theeffects of synthesis temperature and time on the ultraviolet maximum absorption wavelength andits adsorption rate of the modified hyperbranched polymer were studied, and the synthesisconditions were optimized, the structure of the modified polymer was characterized by FT-IR、UV-Vis and NMR, the particle size of nano-silver were measured, and compared with that of nano silver sol prepared with succinic anhydride modified hyperbranched polymer as template.The results showed the optimal conditions of synthesis process were that: n(MAH):n(DETA) was1:20, the temperature was150℃, and the time was1h.The analysis resule of FT-IR、UV-Vis andNMR proved that maleic anhydride were reaction with amino, make the branches ofhyperbranched polymer crosslinked,the aim of maleic anhydride modifing hyperbranchedpolymer came true.Compared with that of the nano-silver prepared with succinic anhydridemodified hyperbranched polymers as template, the particle size of nano-silver prepared withmaleic anhydride modified hyperbranched polymers was small. The results indicated that maleicanhydride modifing hyperbranched polymers can effectively reduce the aggregation ofnano-silver.（2）Study on the application of modified hyperbranched polymer on antibacterial finishing ofcotton fabric with nano-sliver. By using the complexing and reduction properties of modifiedhyperbranched polymer to silver ions，Ag+/polymer finishing liquid was compounded and usedto prepare nano-silver finished cotton fabric by dipping and steaming technology of finishing.The influence of finishing factors on silver content on the finished fabric were studied, theprocess conditions were optimized, the silver content on fabrics, antibacterial property andwashing resistance of finished fabrics were tested. The fiber surface of the finished fabric wasobserved by SEM, and the physical and mechanical properties were measured. The optimumprocess conditions of nano-silver finishing were that dipping time was30min, steaming time was45min, When the concentration of silver nitrate was0.5mmol/L, the bacterial inhibition rate forbacillus coli and staphylococcus aureus of the finished fabric both reached99.9%, after beingwashed50times, the bacterial inhibition rate for these two kinds of bacteria of the finished fabricwere over94%. Compared with that of the nano-silver prepared with succinic anhydridemodified hyperbranched polymers as template, the silver content of fabric prepared with maleicanhydride modified hyperbranched polymers was higher, the aggregation of nano-silver was less,the particle size of nano-silver was smaller. Compared with cotton fabric, the finished fabricprepared with maleic anhydride modified hyperbranched polymers as template have no effect onthe tear strength, breaking strength and softness of the fabric. The study indicated that the cottonfabric nano-silver finishing by the method of modified hyperbranched polymer as template can effectively reduce the aggregation of nano-silver, and the physical and mechanical properties ofthe finished fabric have no change to the cotton fabric.By comparing the above two kinds of antibacterial finishing process of cotton fabric withnano-silver, the utilization rate of silver ion of nano-silver finishing of maleic acid modifiedmethyl acrylamide grafted cotton fabric by the method of silver ions for being adsorbed bydipping and for being reduced by steaming was high, and the washing durability of finishedfabric was well, but the bad effect of the finishing prosess on physical and mechanical propertiesof the cotton fabric was large. The utilization rate of silver ion and the washing durability offinished fabric prepared with maleic anhydride modified hyperbranched polymers as templatewere relatively low, but could meet the needs of the finishing production and useof the finishedfabric, and the finishing process technology had no influence on physical and mechanicalproperties of the finished cotton fabric. Therefore, nano-silver finishing of cotton fabrics bymethod of maleic anhydride modified hyperbranched polymers as template was an idealantibacterial finishing process which could effectively reduced the aggregation of nano-silver.