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Today, functional fabrics with antibacterial properties are more popular. However, cost-effective production of functional fabrics with durable and consistent performance remains a challenge. Polyvinyl alcohol (PVA) was used to modify polypropylene (PP) nonwoven fabric, and then silver nanoparticles (AgNPs) were deposited in situ to produce PVA-modified AgNPs-loaded PP (referred to as AgNPs). /PVA/PP) fabric. Encapsulation of PP fibers using PVA coating helps to significantly improve the adhesion of loaded Ag NPs to PP fibers, and Ag/PVA/PP nonwovens exhibit significantly improved mechanical properties and resistance to Escherichia coli (referred to as E. coli). Generally, Ag/PVA/PP nonwoven fabric produced at 30mM silver ammonia concentration has better mechanical properties, and the antibacterial protection rate against E. coli reaches 99.99%. The fabric still retains excellent antibacterial activity after 40 washes and has the potential for repeated use. In addition, Ag/PVA/PP non-woven fabric has wide application prospects in industry due to its good air permeability and moisture permeability. In addition, we have also developed a roll-to-roll technology and conducted preliminary exploration to test the feasibility of this method.
With the deepening of economic globalization, large-scale population movements have greatly increased the possibility of virus transmission, which well explains why the novel coronavirus has such a strong ability to spread around the world and is difficult to prevent1,2,3. In this sense, there is an urgent need to develop new antibacterial materials, such as polypropylene (PP) nonwovens, as medical protective materials. Polypropylene non-woven fabric has the advantages of low density, chemical inertness and low cost4, but does not have antibacterial ability, short service life and low protection efficiency. Therefore, it is of great importance to impart antibacterial properties to PP nonwoven materials.
As an ancient antibacterial agent, silver has gone through five stages of development: colloidal silver solution, silver sulfadiazine, silver salt, protein silver and nanosilver. Silver nanoparticles are increasingly used in fields such as medicine5,6, conductivity7,8,9, surface-enhanced Raman scattering10,11,12, catalytic degradation of dyes13,14,15,16 etc. In particular, silver nanoparticles ( AgNPs) have advantages over traditional antimicrobial agents such as metal salts, quaternary ammonium compounds and triclosan due to their required bacterial resistance, stability, low cost and environmental acceptability17,18,19. In addition, silver nanoparticles with large specific surface area and high antibacterial activity can be attached to wool fabrics20, cotton fabrics21,22, polyester fabrics and other fabrics to achieve controlled, sustained release of antibacterial silver particles23,24. This means that by encapsulating AgNPs, it is possible to create PP fabrics with antibacterial activity. However, PP nonwovens lack functional groups and have low polarity, which is not conducive to the encapsulation of AgNPs. To overcome this drawback, some researchers have attempted to deposit Ag nanoparticles on the surface of PP fabrics using various modification methods including plasma spraying26,27, radiation grafting28,29,30,31 and surface coating32. For example, Goli et al. [33] introduced a protein coating on the surface of PP nonwoven fabric, the amino acids at the periphery of the protein layer can serve as anchor points for the binding of AgNPs, thereby achieving good antibacterial properties. activity. Li and co-workers 34 found that N-isopropylacrylamide and N-(3-aminopropyl)methacrylamide hydrochloride co-grafted by ultraviolet (UV) etching exhibited strong antimicrobial activity, although the UV etching process is complex and can degrade the mechanical properties. fibers . Oliani et al prepared Ag NPs-PP gel films with excellent antibacterial activity by pretreating pure PP with gamma irradiation, but their method was also complex. Thus, it remains a challenge to efficiently and easily produce recyclable polypropylene nonwovens with desired antimicrobial activity.
In this study, polyvinyl alcohol, an environmentally friendly and low-cost membrane material with good film-forming ability, high hydrophilicity, and excellent physical and chemical stability, is used to modify polypropylene fabrics. Glucose is used as a reducing agent36. An increase in the surface energy of the modified PP promotes the selective deposition of AgNPs. Compared with pure PP fabric, the prepared Ag/PVA/PP fabric showed good recyclability, excellent antibacterial activity against E. coli, good mechanical properties even after 40 washing cycles, and significant breathability, sex and moisture permeability.
The PP nonwoven fabric with a specific weight of 25 g/m2 and a thickness of 0.18 mm was provided by Jiyuan Kang’an Sanitary Materials Co., Ltd. (Jiyuan, China) and cut into sheets measuring 5×5 cm2. Silver nitrate (99.8%; AR) was purchased from Xilong Scientific Co., Ltd. (Shantou, China). Glucose was purchased from Fuzhou Neptune Fuyao Pharmaceutical Co., Ltd. (Fuzhou, China). Polyvinyl alcohol (industrial grade reagent) was purchased from Tianjin Sitong Chemical Factory (Tianjin, China). Deionized water was used as a solvent or rinse and was prepared in our laboratory. Nutrient agar and broth were purchased from Beijing Aoboxing Biotechnology Co., Ltd. (Beijing, China). E. coli strain (ATCC 25922) was purchased from Zhangzhou Bochuang Company (Zhangzhou, China).
The resulting PP tissue was washed with ultrasound in ethanol for 15 minutes. The resulting PVA was added to water and heated at 95°C for 2 hours to obtain an aqueous solution. Then glucose was dissolved in 10 ml of PVA solution with a mass fraction of 0.1%, 0.5%, 1.0% and 1.5%. The purified polypropylene nonwoven fabric was immersed in a PVA/glucose solution and heated at 60°C for 1 hour. After heating is completed, the PP-impregnated nonwoven fabric is removed from the PVA/glucose solution and dried at 60°C for 0.5 h to form a PVA film on the surface of the web, thereby obtaining a PVA/PP composite. textile.
Silver nitrate is dissolved in 10 ml of water with constant stirring at room temperature and ammonia is added dropwise until the solution changes from clear to brown and clear again to obtain silver ammonia solution (5–90 mM). Place PVA/PP nonwoven fabric in silver ammonia solution and heat it at 60°C for 1 hour to form Ag nanoparticles in situ on the surface of the fabric, then rinse it with water three times and dry at 60°C. C for 0.5 h to obtain Ag/PVA/PP composite fabric.
After preliminary experiments, we built roll-to-roll equipment in the laboratory for large-scale production of composite fabrics. The rollers are made of PTFE to avoid adverse reactions and contamination. During this process, the impregnation time and the amount of adsorbed solution can be controlled by adjusting the speed of the rollers and the distance between the rollers to obtain the desired Ag/PVA/PP composite fabric.
The tissue surface morphology was studied using a VEGA3 scanning electron microscope (SEM; Japan Electronics, Japan) at an accelerating voltage of 5 kV. The crystal structure of silver nanoparticles was analyzed by X-ray diffraction (XRD; Bruker, D8 Advanced, Germany; Cu Kα radiation, λ = 0.15418 nm; voltage: 40 kV, current: 40 mA) in the range of 10–80°. 2θ. A Fourier transform infrared spectrometer (ATR-FTIR; Nicolet 170sx, Thermo Fisher Scientific Incorporation) was used to analyze the chemical properties of surface-modified polypropylene fabric. The PVA modifier content of Ag/PVA/PP composite fabrics was measured by thermogravimetric analysis (TGA; Mettler Toledo, Switzerland) under a nitrogen stream. Inductively coupled plasma mass spectrometry (ICP-MS, ELAN DRC II, Perkin-Elmer (Hong Kong) Co., Ltd.) was used to determine the silver content of Ag/PVA/PP composite fabrics.
The air permeability and water vapor transmission rate of Ag/PVA/PP composite fabric (specification: 78×50cm2) were measured by a third-party testing agency (Tianfangbiao Standardization Certification and Testing Co., Ltd.) in accordance with GB/T. 5453-1997 and GB/T 12704.2-2009. For each sample, ten different points are selected for testing, and the data provided by the agency is the average of the ten points.
The antibacterial activity of Ag/PVA/PP composite fabric was measured in accordance with Chinese standards GB/T 20944.1-2007 and GB/T 20944.3- using agar plate diffusion method (qualitative analysis) and shake flask method (quantitative analysis). . respectively in 2008. The antibacterial activity of Ag/PVA/PP composite fabric against Escherichia coli was determined at different washing times. For the agar plate diffusion method, the test Ag/PVA/PP composite fabric is punched into a disk (diameter: 8 mm) using a punch and attached to an agar Petri dish inoculated with Escherichia coli (ATCC 25922). ; 3.4 × 108 CFU ml-1) and then incubated at 37°C and 56% relative humidity for approximately 24 hours. The zone of inhibition was analyzed vertically from the center of the disk to the inner circumference of the surrounding colonies. Using the shake flask method, a 2 × 2 cm2 flat plate was prepared from the tested Ag/PVA/PP composite fabric and autoclaved in a broth environment at 121°C and 0.1 MPa for 30 minutes. After autoclaving, the sample was immersed in a 5-mL Erlenmeyer flask containing 70 mL of broth culture solution (suspension concentration 1 × 105–4 × 105 CFU/mL) and then incubated at an oscillating temperature of 150 °C. rpm and 25°C for 18 hours. After shaking, collect a certain amount of bacterial suspension and dilute it tenfold. Collect the required amount of diluted bacterial suspension, spread it on agar medium and culture at 37°C and 56% relative humidity for 24 hours. The formula for calculating antibacterial effectiveness is: \(\frac{\mathrm{C}-\mathrm{A}}{\mathrm{C}}\cdot 100\%\), where C and A are the number of colonies after 24 hours, respectively. Cultured in blank control group and Ag/PVA/PP composite fabric.
The durability of Ag/PVA/PP composite fabrics was evaluated by washing according to ISO 105-C10:2006.1A. During washing, immerse the test Ag/PVA/PP composite fabric (30x40mm2) in an aqueous solution containing commercial detergent (5.0g/L) and wash it at 40±2 rpm and 40±5 rpm /min. high speed. °C 10, 20, 30, 40 and 50 cycles. After washing, the fabric is rinsed three times with water and dried at a temperature of 50-60°C for 30 minutes. The change in silver content after washing was measured to determine the degree of antibacterial activity.
Figure 1 shows the schematic diagram of the fabrication of Ag/PVA/PP composite fabric. That is, PP nonwoven material is immersed in a mixed solution of PVA and glucose. The PP-impregnated non-woven material is dried to fix the modifier and reducing agent to form a sealing layer. The dried polypropylene nonwoven fabric is immersed in a silver ammonia solution to deposit the silver nanoparticles in situ. The concentration of the modifier, the molar ratio of glucose to silver ammonia, the concentration of silver ammonia and the reaction temperature affect the precipitation of Ag NPs. are important factors. Figure 2a shows the dependence of the water contact angle of the Ag/PVA/PP fabric on the modifier concentration. When the modifier concentration increases from 0.5 wt.% to 1.0 wt.%, the contact angle of the Ag/PVA/PP fabric decreases significantly; when the modifier concentration increases from 1.0 wt.% to 2.0 wt.%, it practically does not changes. Figure 2 b shows SEM images of pure PP fibers and Ag/PVA/PP fabrics prepared at 50 mM silver ammonia concentration and different molar ratios of glucose to silver ammonia (1:1, 3:1, 5:1, and 9:1). . image. ). The resulting PP fiber is relatively smooth. After encapsulation with a PVA film, some of the fibers are fastened together; due to the deposition of silver nanoparticles, the fibers become relatively rough. As the molar ratio of the reducing agent to glucose increases, the deposited layer of Ag NPs gradually thickens, and as the molar ratio increases to 5:1 and 9:1, Ag NPs tend to form aggregates. Macroscopic and microscopic images of PP fiber become more uniform, especially when the molar ratio of reducing agent to glucose is 5:1. Digital photographs of the corresponding samples obtained at 50 mM silver ammonia are shown in Figure S1.
Changes in the water contact angle of Ag/PVA/PP fabric at different PVA concentrations (a), SEM images of Ag/PVA/PP fabric obtained at a silver ammonia concentration of 50 mM and various molar ratios of glucose and silver ammonia [(b))) ; (1) PP fiber, (2) PVA/PP fiber, (3) molar ratio 1:1, (4) molar ratio 3:1, (5) molar ratio 5:1, (6) molar ratio 9: 1], X-ray diffraction pattern (c) and SEM image (d) of Ag/PVA/PP fabric obtained at silver ammonia concentrations: (1) 5 mM, (2) 10 mM, (3) 30 mM, (4) 50 mM , (5) 90 mM and (6) Ag/PP-30 mM. The reaction temperature is 60°C.
In Fig. Figure 2c shows the X-ray diffraction pattern of the resulting Ag/PVA/PP fabric. In addition to the diffraction peak of PP fiber 37, four diffraction peaks at 2θ = ∼ 37.8°, 44.2°, 64.1° and 77.3° correspond to (1 1 1), (2 0 0), (2 2 0), Crystal plane (3 1 1) of cubic face-centered silver nanoparticles. As the silver ammonia concentration increases from 5 to 90 mM, the XRD patterns of Ag become sharper, consistent with a subsequent increase in crystallinity. According to Scherrer’s formula, the grain sizes of Ag nanoparticles prepared with 10 mM, 30 mM and 50 mM silver ammonia were calculated to be 21.3 nm, 23.3 nm and 26.5 nm, respectively. This is because the silver ammonia concentration is the driving force behind the reduction reaction to form metallic silver. With increasing concentration of silver ammonia, the rate of nucleation and growth of Ag NPs increases. Figure 2d shows the SEM images of Ag/PVA/PP fabrics obtained at different concentrations of Ag ammonia. At a silver ammonia concentration of 30 mM, the deposited layer of Ag NPs is relatively homogeneous. However, when the silver ammonia concentration is too high, the uniformity of the Ag NP deposition layer tends to decrease, which may be due to strong agglomeration in the Ag NP deposition layer. In addition, silver nanoparticles on the surface have two shapes: spherical and scaly. The spherical particle size is approximately 20–80 nm, and the lamellar lateral size is approximately 100–300 nm (Figure S2). The deposition layer of Ag nanoparticles on the surface of unmodified PP fabric is uneven. In addition, increasing the temperature promotes the reduction of Ag NPs (Fig. S3), but too high a reaction temperature does not promote the selective precipitation of Ag NPs.
Figure 3a schematically depicts the relationship between the silver ammonia concentration, the amount of deposited silver, and the antibacterial activity of the prepared Ag/PVA/PP fabric. Figure 3b shows the antibacterial patterns of the samples at different concentrations of silver ammonia, which can directly reflect the antibacterial status of the samples. When the silver ammonia concentration increased from 5 mM to 90 mM, the amount of silver precipitation increased from 13.67 g/kg to 481.81 g/kg. In addition, as the amount of silver deposition increases, the antibacterial activity against E. coli initially increases and then remains at a high level. Specifically, when the silver ammonia concentration is 30 mM, the deposition amount of silver in the resulting Ag/PVA/PP fabric is 67.62 g/kg, and the antibacterial rate is 99.99%. and select this sample as a representative for subsequent structural characterization.
(a) Relationship between the level of antibacterial activity and the amount of Ag layer applied and the concentration of silver ammonia; (b) Photographs of bacterial culture plates taken with a digital camera showing blank samples and samples prepared using 5 mM, 10 mM, 30 mM, 50 mM and 90 mM silver ammonia. Antibacterial activity of Ag/PVA/PP fabric against Escherichia coli
Figure 4a shows the FTIR/ATR spectra of PP, PVA/PP, Ag/PP and Ag/PVA/PP. The absorption bands of pure PP fiber at 2950 cm-1 and 2916 cm-1 are due to the asymmetric stretching vibration of the –CH3 and –CH2- groups, and at 2867 cm-1 and 2837 cm-1 they are due to the symmetric stretching vibration of the –CH3 and –CH2 groups –. –CH3 and –CH2–. The absorption bands at 1375 cm–1 and 1456 cm–1 are attributed to asymmetric and symmetric shift vibrations of –CH338.39. The FTIR spectrum of Ag/PP fiber is similar to that of PP fiber. In addition to the absorption band of PP, the new absorption peak at 3360 cm-1 of PVA/PP and Ag/PVA/PP fabrics is attributed to the stretching of the hydrogen bond of the –OH group. This shows that PVA is successfully applied to the surface of polypropylene fiber. In addition, the hydroxyl absorption peak of Ag/PVA/PP fabric is slightly weaker than that of PVA/PP fabric, which may be due to the coordination of some hydroxyl groups with silver.
FT-IR spectrum (a), TGA curve (b) and XPS measurement spectrum (c) of pure PP, PVA/PP fabric and Ag/PVA/PP fabric, and C 1s spectrum of pure PP (d), PVA/PP PP fabric (e) and Ag 3d peak (f) of Ag/PVA/PP fabric.
In Fig. Figure 4c shows the XPS spectra of PP, PVA/PP, and Ag/PVA/PP fabrics. The weak O 1s signal of pure polypropylene fiber can be attributed to the oxygen element adsorbed on the surface; the C 1s peak at 284.6 eV is attributed to CH and CC (see Figure 4d). Compared with pure PP fiber, PVA/PP fabric (Fig. 4e) shows high performance at 284.6 eV (C–C/C–H), 285.6 eV (C–O–H), 284.6 eV (C–C/C–H), 285.6 eV (C–O–H) and 288.5 eV (H–C=O)38. In addition, the O 1s spectrum of PVA/PP fabric can be approximated by two peaks at 532.3 eV and 533.2 eV41 (Fig. S4), these C 1s peaks correspond to C–OH and H–C=O (hydroxyl groups of PVA and aldehyde glucose group), which is consistent with the FTIR data. The Ag/PVA/PP nonwoven fabric retains the O 1s spectrum of C-OH (532.3 eV) and HC=O (533.2 eV) (Figure S5), consisting of 65.81% (atomic percent) C, 22. 89. % O and 11.31% Ag (Fig. S4). In particular, the peaks of Ag 3d5/2 and Ag 3d3/2 at 368.2 eV and 374.2 eV (Fig. 4f) further prove that Ag NPs are doped on the surface of PVA/PP42 nonwoven fabric.
The TGA curves (Fig. 4b) of pure PP, Ag/PP fabric, and Ag/PVA/PP fabric show that they undergo similar thermal decomposition processes, and the deposition of Ag NPs leads to a slight increase in the thermal degradation temperature of PP. fibers PVA/PP fibers (from 480 °C (PP fibers) to 495 °C), possibly due to the formation of an Ag barrier43. At the same time, the residual amounts of pure samples of PP, Ag/PP, Ag/PVA/PP, Ag/PVA/PP-W50 and Ag/PP-W50 after heating at 800°C were 1.32%, 16.26% and 13. 86%. % respectively 9.88% and 2.12% (the suffix W50 here refers to 50 wash cycles). The remainder of pure PP is attributed to impurities, and the remainder of the remaining samples to Ag NPs, and the difference in the residual amount of samples loaded with silver should be due to different amounts of silver nanoparticles loaded on them. In addition, after washing Ag/PP fabric 50 times, the residual silver content was reduced by 94.65%, and the residual silver content of Ag/PVA/PP fabric was reduced by about 31.74%. This shows that PVA encapsulating coating can effectively improve the adhesion of AgNPs to the PP matrix.
To evaluate wearing comfort, the air permeability and water vapor transmission rate of the prepared polypropylene fabric were measured. Generally speaking, breathability is related to the user’s thermal comfort, especially in hot and humid environments44. As shown in Figure 5a, the air permeability of pure PP is 2050 mm/s, and after modification of PVA it decreases to 856 mm/s. This is because the PVA film formed on the surface of the PP fiber and the woven part helps reduce the gaps between the fibers. After applying Ag NPs, the air permeability of the PP fabric increases due to the consumption of PVA coating when applying Ag NPs. In addition, the breathability of Ag/PVA/PP fabrics tends to decrease as the silver ammonia concentration increases from 10 to 50 mmol. This may be due to the fact that the thickness of the silver deposit increases with increasing silver ammonia concentration, which helps reduce the number of pores and the likelihood of water vapor passing through them.
(a) Air permeability of Ag/PVA/PP fabrics prepared with different concentrations of silver ammonia; (b) Water vapor transmission of Ag/PVA/PP fabrics prepared with different concentrations of silver ammonia; (c) Various modifiers Tensile curve of Ag Fabric/PVA/PP obtained at different concentrations; (d) Tensile curve of Ag/PVA/PP fabric obtained at different concentrations of silver ammonia (Ag/PVA/PP fabric obtained at 30 mM silver ammonia concentration is also shown) (Compare the tensile curves of PP fabrics after 40 washing cycles).
The rate of water vapor transmission is another important indicator of the thermal comfort of a fabric45. It turns out that the moisture permeability of fabrics is mainly influenced by breathability and surface properties. That is, air permeability mainly depends on the number of pores; surface properties affect the moisture permeability of hydrophilic groups through adsorption-diffusion-desorption of water molecules. As shown in Figure 5b, the moisture permeability of pure PP fiber is 4810 g/(m2·24h). After sealing with PVA coating, the number of holes in the PP fiber decreases, but the moisture permeability of the PVA/PP fabric increases to 5070 g/(m2·24 h), since its moisture permeability is mainly determined by the surface properties. not pores. After deposition of AgNPs, the moisture permeability of Ag/PVA/PP fabric was further increased. In particular, the maximum moisture permeability of Ag/PVA/PP fabric obtained at a silver ammonia concentration of 30 mM is 10300 g/(m2·24h). At the same time, different moisture permeability of Ag/PVA/PP fabrics obtained at different concentrations of silver ammonia may be associated with differences in the thickness of the silver deposition layer and the number of its pores.
The mechanical properties of fabrics strongly influence their service life, especially as recyclable materials46. Figure 5c shows the tensile stress curve of Ag/PVA/PP fabric. The tensile strength of pure PP is only 2.23 MPa, while the tensile strength of 1 wt% PVA/PP fabric is significantly increased to 4.56 MPa, indicating that the encapsulation of PVA PP fabric helps to significantly improve its mechanical properties. properties. The tensile strength and elongation at break of PVA/PP fabric increase with increasing concentration of PVA modifier because the PVA film can break the stress and strengthen the PP fiber. However, when the modifier concentration increases to 1.5 wt.%, sticky PVA makes the polypropylene fabric stiff, which seriously affects wearing comfort.
Compared with pure PP and PVA/PP fabrics, the tensile strength and elongation at break of Ag/PVA/PP fabrics are further improved because Ag nanoparticles uniformly distributed on the surface of PP fibers can distribute the load47,48. It can be seen that the tensile strength of Ag/PP fiber is higher than that of pure PP, reaching 3.36 MPa (Fig. 5d), which confirms the strong and strengthening effect of Ag NPs. In particular, the Ag/PVA/PP fabric produced at a silver ammonia concentration of 30 mM (instead of 50 mM) exhibits maximum tensile strength and elongation at break, which is still due to the uniform deposition of Ag NPs as well as the uniform deposition. Aggregation of silver NPs under conditions of high concentration of silver ammonia. In addition, after 40 washing cycles, the tensile strength and elongation at break of Ag/PVA/PP fabric prepared at 30 mM silver ammonia concentration decreased by 32.7% and 26.8%, respectively (Fig. 5d), which may associated with a small loss of silver nanoparticles deposited after this.
Figures 6a and b show digital camera photographs of Ag/PVA/PP fabric and Ag/PP fabric after washing for 0, 10, 20, 30, 40, and 50 cycles at 30 mM silver ammonia concentration. Dark gray Ag/PVA/PP fabric and Ag/PP fabric gradually become light gray after washing; and the color change of the first during washing does not seem to be as serious as that of the second. In addition, compared with Ag/PP fabric, the silver content of Ag/PVA/PP fabric decreased relatively slowly after washing; after washing 20 or more times, the former retained a higher silver content than the latter (Fig. 6c). This indicates that encapsulating PP fibers with PVA coating can significantly improve the adhesion of Ag NPs to PP fibers. Figure 6d shows the SEM images of Ag/PVA/PP fabric and Ag/PP fabric after washing for 10, 40, and 50 cycles. Ag/PVA/PP fabrics experience less loss of Ag NPs during washing than Ag/PP fabrics, again because the PVA encapsulating coating helps improve the adhesion of Ag NPs to PP fibers.
(a) Photographs of Ag/PP fabric taken with a digital camera (taken at 30 mM silver ammonia concentration) after washing for 0, 10, 20, 30, 40 and 50 cycles (1-6); (b) Ag/PVA/PP Photographs of fabrics taken with a digital camera (taken at 30 mM silver ammonia concentration) after washing for 0, 10, 20, 30, 40 and 50 cycles (1-6); (c) Changes in silver content of the two fabrics across wash cycles; (d) SEM images of Ag/PVA/PP fabric (1-3) and Ag/PP fabric (4-6) after 10, 40 and 50 washing cycles.
Figure 7 shows the antibacterial activity and digital camera photographs of Ag/PVA/PP fabrics against E. coli after 10, 20, 30 and 40 wash cycles. After 10 and 20 washes, the antibacterial performance of Ag/PVA/PP fabrics remained at 99.99% and 99.93%, demonstrating excellent antibacterial activity. The antibacterial level of Ag/PVA/PP fabric decreased slightly after 30 and 40 times of washing, which was due to the loss of AgNPs after long-term washing. However, the antibacterial rate of Ag/PP fabric after 40 washes is only 80.16%. It is obvious that the antibacterial effect of Ag/PP fabric after 40 washing cycles is much less than that of Ag/PVA/PP fabric.
(a) Level of antibacterial activity against E. coli. (b) For comparison, photographs of the Ag/PVA/PP fabric taken with a digital camera after washing the Ag/PP fabric at 30 mM silver ammonia concentration for 10, 20, 30, 40 and 40 cycles are also shown.
In Fig. Figure 8 schematically shows the fabrication of large-scale Ag/PVA/PP fabric using a two-stage roll-to-roll route. That is, the PVA/glucose solution was soaked in the roll frame for a certain period of time, then taken out, and then impregnated with silver ammonia solution in the same way to obtain Ag/PVA/PP fabric. (Fig. 8a). The resulting Ag/PVA/PP fabric still retains excellent antibacterial activity even if left for 1 year. For large-scale preparation of Ag/PVA/PP fabrics, the resulting PP nonwovens were impregnated in a continuous roll process and then passed through a PVA/glucose solution and a silver ammonia solution sequentially and processed. two methods. Attached videos. The impregnation time is controlled by adjusting the speed of the roller, and the amount of adsorbed solution is controlled by adjusting the distance between the rollers (Fig. 8b), thereby obtaining the target Ag/PVA/PP nonwoven fabric of large size (50 cm × 80 cm). ) and collection roller. The whole process is simple and efficient, which is conducive to large-scale production.
Schematic diagram of the production of large-sized target products (a) and schematic diagram of the roll process for the production of Ag/PVA/PP nonwoven materials (b).
Silver-containing PVA/PP nonwovens are produced using a simple in-situ liquid phase deposition technology combined with the roll-to-roll route. Compared with PP fabric and PVA/PP fabric, the mechanical properties of the prepared Ag/PVA/PP nonwoven fabric are significantly improved because the PVA sealing layer can significantly improve the adhesion of Ag NPs to PP fibers. In addition, the loading amount of PVA and the content of silver NPs in the Ag/PVA/PP nonwoven fabric can be well controlled by adjusting the concentrations of PVA/glucose solution and silver ammonia solution. In particular, Ag/PVA/PP nonwoven fabric prepared using 30 mM silver ammonia solution showed the best mechanical properties and retained excellent antibacterial activity against E. coli even after 40 washing cycles, showing good anti-fouling potential. PP non-woven material. Compared to other literature data, the fabrics obtained by us using simpler methods showed better resistance to washing. In addition, the resulting Ag/PVA/PP nonwoven fabric has ideal moisture permeability and wearing comfort, which can facilitate its application in industrial applications.
Include all data obtained or analyzed during this study (and their supporting information files).
Russell, S.M. et al. Biosensors to combat the COVID-19 cytokine storm: challenges ahead. ACS Sens. 5, 1506–1513 (2020).
Zaeem S, Chong JH, Shankaranarayanan V and Harkey A. COVID-19 and multi-organ responses. current. question. heart. 45, 100618 (2020).
Zhang R, et al. Estimates of the number of coronavirus cases in 2019 in China are adjusted by stage and endemic regions. front. medicine. 14, 199–209 (2020).
Gao J. et al. Flexible, superhydrophobic and highly conductive nonwoven polypropylene fabric composite material for electromagnetic interference protection. Chemical. engineer. J. 364, 493–502 (2019).
Raihan M. et al. Development of multifunctional polyacrylonitrile/silver nanocomposite films: antibacterial activity, catalytic activity, conductivity, UV protection and active SERS sensors. J.Matt. resource. technologies. 9, 9380–9394 (2020).
Dawadi S, Katuwal S, Gupta A, Lamichane U and Parajuli N. Current research on silver nanoparticles: synthesis, characterization and applications. J. Nanomaterials. 2021, 6687290 (2021).
Deng Da, Chen Zhi, Hu Yong, Ma Jian, Tong Y.D.N. A simple process for preparing silver-based conductive ink and applying it to frequency-selective surfaces. Nanotechnology 31, 105705–105705 (2019).
Hao, Y. et al. Hyperbranched polymers enable the use of silver nanoparticles as stabilizers for inkjet printing of flexible circuits. R. Shuker. Chemical. 43, 2797–2803 (2019).
Keller P and Kawasaki HJML Conductive leaf vein networks produced by self-assembly of silver nanoparticles for potential applications in flexible sensors. Matt. Wright. 284, 128937.1-128937.4 (2020).
Li, J. et al. Silver nanoparticle-decorated silica nanospheres and arrays as potential substrates for surface-enhanced Raman scattering. ASU Omega 6, 32879–32887 (2021).
Liu, X. et al. Large-scale flexible surface enhanced Raman scattering sensor (SERS) with high signal stability and uniformity. ACS Application Matt. Interfaces 12, 45332–45341 (2020).
Sandeep, K.G. et al. A hierarchical heterostructure of fullerene nanorods decorated with silver nanoparticles (Ag-FNRs) serves as an effective single-particle independent SERS substrate. physics. Chemical. Chemical. physics. 27, 18873–18878 (2018).
Emam, H.E. and Ahmed, H.B. Comparative study of homometallic and heterometallic agar-based nanostructures during dye-catalyzed degradation. internationality. J. Biol. Large molecules. 138, 450–461 (2019).
Emam, H.E., Mikhail, M.M., El-Sherbiny, S., Nagy, K.S. and Ahmed, H.B. Metal-dependent nanocatalysis for aromatic pollutant reduction. Wednesday. the science. pollute. resource. internationality. 27, 6459–6475 (2020).
Ahmed H.B. and Emam H.E. Triple core-shell (Ag-Au-Pd) nanostructures grown from seeds at room temperature for potential water purification. polymer. test. 89, 106720 (2020).
Post time: Nov-21-2023