Green Preparation Of Nanosilver Solution And Antibacterial Finishing Of Cotton Fabrics

Nanosilver is a highly effective,inexpensive and easy to produce antimicrobial agent.However,its large specific surface area makes it prone to agglomeration and sedimentation,making it difficult to store.To solve this problem,we developed a green process for producing silver nanoparticles and created a stable PA/TEA@AgNPs antimicrobial material system that can be dispersed in water.We then investigated how this system could be used for the antimicrobial treatment of cotton fabrics.Our process involves dissolving phytic acid in water to form micelles that can complex with silver ions,adding triethanolamine to encapsulate silver ions and adjust the p H of the solution,and finally synthesising silver nanoparticles with a reducing agent.This study proposes a feasible strategy to solve the stability problem of using silver nanoparticles as antibacterial agents in industrial applications.The contents are as follows:(1)Preparation and process optimisation of PA/TEA@AgNPs: The synthesis process of PA/TEA@AgNPs was optimised by adjusting the PA concentration,p H,reducing agent concentration,time and temperature.The optimum process was: the molar concentration ratio of phytic acid to silver nitrate was 2:1,p H=9;when glucose was used as the reducing agent,the molar concentration ratio of glucose to silver nitrate was 4:1,the reduction temperature was80 ℃,and the reduction time was 100 min;when sodium citrate was used as the reducing agent,the molar concentration ratio of sodium citrate to silver nitrate was 3:1,the reduction temperature was 90 ℃,and the reduction time was 80 min.(2)Characterisation of PA/TEA@AgNPs: The crystalline structure,microscopic morphology,size,elemental composition,storage stability and centrifugal stability of the prepared PA/TEA@AgNPs were analysed by XRD,UV-vis,DLS and FE-TEM respectively.Spherical silver nanoparticles of around 20 nm were successfully encapsulated in PA and TEA.The storage stability results showed that the PA/TEA@AgNPs system could be stored at room temperature for at least 120 days without protection from light,and the centrifugal stability showed that the PA/TEA@AgNPs system could remain stable after centrifugation at 6000r/min for 50 min.After centrifugation at 6000 r/min for 200 min,the silver nanoparticles were dispersed in the aqueous solution again,and the size of the silver nanoparticles did not change.(3)Process study and performance characterisation of PA/TEA@AgNPs finishing on cotton fabrics: The effects of different impregnation temperature,time,concentration,baking time and temperature;the effects of impregnation concentration,baking time and temperature on the inhibition rate of cotton fabrics were investigated.The results showed that: the cotton fabric was impregnated with 10% nano-silver solution in a bath ratio of 1:30,impregnated at30 ℃ for 20 min,baked at 140 ℃ for 90 s;the cotton fabric was dipped and rolled twice with10% nano-silver solution,the ginning rate was 80 %,baked at 140 ℃ for 90 s.The antibacterial cotton fabric still had 97.50 % bacterial inhibition rate after 10 washes after dipping and rolling.The colour difference of the cotton fabric after dipping and rolling(35)E<1and the antibacterial rate all reached 99.99 %.(4)Microscopic morphology and structural characterisation of the antibacterial cotton fabric: SEM,EDS,XPS and FT-IR tests were carried out to characterise the antibacterial finish of the cotton fabric.XPS and FT-IR analysis showed that the PA/TEA@AgNPs were successfully coated on the cotton fabric and the silver nanoparticles were not oxidised after the finishing.