Research on the dispersion of nanopowder and antibacterial finishing of cotton fabrics

Research on the dispersion of nanopowder and antibacterial finishing of cotton fabric

In recent years, with the advancement of science and technology and the improvement of people’s living standards, people’s understanding and use of materials have progressed towards multi-functionality, and the same is true for the fabric industry. Today, when functional and environmentally friendly fabrics have become the mainstream of the world’s fabric market, the development and research of functional fabrics has expanded to many fields, among which the application of nanomaterials is one of them. Natural fiber fabrics are popular among consumers due to their comfort, etc. However, cotton fabrics themselves have some shortcomings. For example, under suitable conditions, some pathogenic bacteria such as Staphylococcus aureus, Escherichia coli and Candida albicans can infect cotton fabrics. Bacteria can easily breed in the wearing environment of some underwear and underwear, and use the body’s metabolic products as nutrients to reproduce rapidly, releasing a disgusting odor. In addition, they can cause discoloration and mildew of cotton products, induce various skin diseases, and harm human health. Since some inorganic materials have superior antibacterial functions after being made into nanometer scale, and nanofunctional materials are heat-resistant, non-toxic and highly stable, nanomaterials are first selected as new antibacterial finishing agents to replace the Bacteriostatic agents that are toxic and irritating to the human body have become an important direction in the development of green functional fabrics.
At present, there are three main methods of applying nanoparticles to fabrics that are being researched and applied at home and abroad: (a) blended chemical fiber fabric silk method (b) post-finishing method: absorption method, PU coating Layer method and padding method (c) Grafting method. However, to this day, the application of nanopowders in fabrics is still a developing technology. This is because nanoparticles have high surface activity, are prone to agglomeration, and are not easy to bind and fix with fiber materials. Therefore, how to disperse nanoparticles evenly on fabrics and achieve a strong combination of nanoparticles and fibers is a key technology for the development and application of nanofunctional fabrics.
This article applies nanopowders TiO2 and ZnO to cotton fabrics with the help of adhesives, and studies their dispersion, antibacterial properties and the synergistic effect of their laminates.
　2 Experimental part
　2·1 Experimental materials and instruments
　2·1·1 Raw materials and reagents
Nano-ZnO and nano-TiO2 (Jiangsu Hehai Nanotechnology Co., Ltd.); Sodium dodecyl benzene sulfonate, sodium hexametaphosphate and sodium silicate (Tianjin Chemical Reagent No. 6 Factory); sodium oligoacrylate (Shanghai Changfeng Chemical Factory); adhesives and penetrants for coloring JFS (Yantai No. 3 Chemical Reagent Factory) and Chemical Reagents Co., Ltd.).
　2·1·2 Fabric specifications
Pre-treated pure cotton fabric: specifications 40/40×133×72.
　2·1·3 Experimental Instruments
Ultrasonic cleaner SK5200H (Shanghai Kedao Ultrasonic Instrument Co., Ltd.) 85-2 constant temperature magnetic stirrer (Changzhou Guohua Electric Co., Ltd.); HH digital display constant temperature water bath (Honghua Instrument Factory, Jintan City, Jiangsu Province); EL-400 stationary pneumatic rolling mill (Shanghai Langao Cloth Equipment Co., Ltd.); Electronic balance (Beijing Sartorius Balance Co., Ltd.); pH 25 acidity meter (Shanghai Hongyi Instrument Factory).
2·2 Dispersion experiment of nanopowder
2·2·1 Selection of optimal dispersant and pH value
Mix 0.10g equal amount of dispersant (sodium polyacrylate, hexametaphosphate Sodium, sodium dodecylbenzene sulfonate, sodium silicate) were added to a beaker containing 100 mL of distilled water. Each dispersant was prepared with six solutions. After stirring, the pH value was accurately adjusted so that the solution containing the same dispersant The pH value of the solution is 5, 6, 7, 8, 9, and 10, and then add 0.15g of nano-adhesive powder (ZnO:TiO2=1:1), and oscillate with an ultrasonic cleaner for 1.5h, then take out 1OmL and put Let it stand for 7 days in a 1OmL test tube, and read the volume of the upper clarified liquid.
2.2.2 Selection of optimal dispersant dosage
Accurately weigh 5 different amounts of sodium polyacrylate and add them to a beaker containing 100 mL of distilled water, and prepare aqueous solutions with different contents in sequence, and adjust pH=9, then add 0.15g nanopowder (ZnO:TiO2=1:1), and shake with an ultrasonic cleaner for 1.5h, then take out 1OmL and put it into a 1OmL test tube and let it stand for 7 days, and read the volume of the upper clarification liquid.
2·3 Antibacterial finishing technology of cotton fabrics
2·3·1 Prescription and conditions
2·3·2 Experimental steps
Weigh fifteen pieces weighing 5.0g For the pure cotton sample, prepare the nano-finishing liquid according to the prescription in 2.3.1. For each prescription, prepare five parts of the finishing liquid according to Table 1, and then immerse the sample in the finishing liquid for 3Omin at 45°C. , then two dips and two rollings, the rolling residue rate is 75%, pre-baked at 80°C for 5 minutes, and baked at 160°C for 3 minutes, to obtain five post-finished samples from 1# to 5#.
Table 1 Mass ratio of nano-ZnO and TiO2 used
——————————– —————-
| Number # | 1 | 2 | 3 | 4 | 5 |
|———|- —–|——–|——|——-|——|
| ZnO:TiO2| 1:0 | 0:1 | 1:1 | 2:1 | 3:1|
　—————————– ——————
　2·4 Determination of antibacterial effect
Conduct antibacterial performance test on cotton fabrics according to fabric industry standard FZ/T01021-92 , the strain used was Staphylococcus aureus.
2.5 Determination of washing resistance
Referring to the GB/T8629-2001 standard, mix 2g/L cleaning solution andPut the washed fabric into the washing machine and wash it according to the 4A program (cleaning program for extraordinary finishing fabrics) to measure its antibacterial performance.
　3 Results and Discussion
　3·1 Effect of dispersant and pH value on dispersion system
　3·1·l Effect of PAA-Na on the dispersion of nanopowder at different pH values
Table 2 The relationship between the volume percentage of the supernatant liquid of the dispersion system and the pH value
—————————- ———————————-
　|PH value of dispersion system | 5 | 6 | 7 | 8 | 9 | 10 |
|————–|——-|——-|—— –|——|——–|——-|
|Clear liquid volume mL | 10 | 4 | 3.6 | 3.6| 1.6 | 1.6|
　|————–|——-|——-|——–|—— |——–|——-|
　|Volume percentage % | 100 | 40 | 36 | 36 | 16 | 16 |
　—— ————————————————– ——-
　3·1·2 The effect of sodium hexametaphosphate on the dispersion of nanopowders at different pH values
Table 3 The volume percentage and pH value of the supernatant liquid of the dispersion system Relationship
———————————————— ——————
　|PH value of dispersion system | 5 | 6 | 7 | 8 | 9 | 10 |
|—- ———-|——-|——-|——–|——|——- -|——-|
|Volume of clarified liquid mL | 10 | 5 | 3.2 | 2.6| 2.0 | 1.8|
|————- -|——-|——-|——–|——|——–|——- |
　|Volume percentage % | 100 | 50 | 32 | 26 | 20 | 18 |
—————————– —————————————-
　3·1·3 SDBS Effect on the dispersion of nanopowders under different pH values
Table 4 Relationship between the volume percentage of supernatant liquid in the dispersion system and pH value
————— ————————————————–
　|PH value of dispersion system | 5 | 6 | 7 | 8 | 9 | 10 |
|————-|——-|- ——|——–|——|——–|——-|
|Clear liquid volume mL | 10 | 10 | 10 | 8.6| 5.8 | 2.2|
　|————-|——-|——|– ——|——|——–|——-|
|Volume % | 100 | 100 | 100 | 80 | 58 | 22 |
　——————————————— ——————–
　3·1·4 Effect of sodium silicate on the dispersion of nanopowders at different pH values
Table 5 The relationship between the volume percentage of the supernatant liquid in the dispersion system and the pH value
——————————– ———————————-
　|PH value of dispersion system | 5 | 6 | 7 | 8 | 9 | 10 |
|————–|——-|——-|——–|– —-|——–|——-|
|Clear liquid volume mL | 10 | 5.6| 3.8 | 2.9| 2.0 | 1.6|
|- ————-|——-|——-|——–|——|—- —-|——-|
　|Volume Percent % | 100 | 56 | 38 | 29 | 20 | 16 |
——————— ————————————————– —
From Table 2 to Table 5, it can be seen that the four dispersants of sodium polyacrylate, sodium hexametaphosphate, sodium dodecylbenzene sulfonate, and sodium silicate all have a stabilizing effect on the nanopowder water dispersion system. . When the same amount of dispersant is added to sodium polyacrylate at pH=9 and pH=10, the volume percentage of the supernatant of the water dispersion system of nanopowder is less and the dispersion effect is good. This is due to the adsorption of the dispersant on the particle surface. The layer produces and strengthens the steric hindrance effect, which increases the steric repulsion energy between particles. At the same time, it also increases the absolute value of the particle surface potential and increases the electrostatic repulsion energy between particles. Therefore, sodium polyacrylate was selected as the dispersant of the nanopowder aqueous dispersion system in the test, and this dispersant was used when pH=9. This is because there is no need to excessively adjust the nanopowder aqueous dispersion during use.The pH value of �� will not introduce impurity particles into subsequent processes.