Electrostatic self-assembly layer by layer technique was used to immobilize ZnO/SiO
2
nanocompsite on cationized cotton fabric. This occurs via the sequential dipping of cotton fabric in dilute ...solutions of poly (diallyldimethylammonium chloride) (PDDA) and ZnO/SiO
2
colloidal suspension nanocomposite of different concentration ratios 1:0, 0:1, 1:1, 2:1, 1:2, and 2:2. The formation of multilayer thin film on cotton fabric creates different functional properties. UV protection properties were monitored at the ratio of (Zn/Si) as well as the number of layers. In the case of 1(Bilayer)BL and 5(Bilayer)BL, increasing the ratio of (ZnO/SiO
2
) within the nano composite (ZnO/SiO
2
) ratio, the UPF increases and the results indicate that the best ultraviolet protection factor is obtained when the Zn/Si ratio is 2. Additionally, dyeing the treated fabric often enhanced protection against ultra violet rays. FTIR spectra were utilized to distinguish the existence of effective groups on the surface of the treated cotton. Scanning electron microscopy studies confirmed successful deposition of the PDDA/(ZnO/SiO
2
) nanocomposite. Moreover, cotton fibers connected together because of the increased coating density and their surface become rougher. Post treatment by stearic acid rendered the fabric water repellent property. Other physical properties such as tensile strength as well as breathability of the cotton fabric were investigated.
Abstract
This article is devoted to the issue of increasing the efficiency of vertical-spindle cotton pickers by rational choice of kinematic and geometrical parameters of the main working body – the ...spindle drum. In particular, in the work, an analysis of the actual operating conditions of the spindles, existing machines, and the results of previous studies in this area indicate the main reasons for the low efficiency of cotton pickers. As a criterion for evaluating the efficiency of the vertical spindles, the “activity” of the spindles and the force that occurs between the cotton boll and the surface of the latter are taken. It is shown that the design features of the existing vertical spindle drums do not allow increasing the active surface of the spindles and their favorable orientation relative to cotton bolls in the collection area. It is substantiated that in order to increase the activity of the spindles in the collection zone, it is necessary to inform them, as they move in this zone, of the variable speed and trajectory of the spindle movement, which improves the conditions for the interaction of the latter with the cotton boll. The obtained results are compared and analyzed with the same results of the existing spindle drums, which showed a significant increase in the activity of the spindles when using elliptical drums as the main working body of the cotton picker.
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•Cotton-MOF-199 showed antibacterial activity (more than 99%) in less than 5 min.•Cotton-MOF systems were synthesized through a friendly environmental in-situ method.•MOFs-cotton ...materials were resistant to Soxhlet and autoclaving processes.•Cotton-MIL-53 (Al+3 based MOF) showed antibacterial activity previously not reported.
Despite antibiotic treatments, bacteria remain outstanding etiological agents of hospital-acquired infections. This work assessed the antimicrobial activity of copper, zinc, and aluminum Metal-Organic framework (MOFs) immobilized onto cotton fibers against nosocomial bacteria. The MOF systems were synthesized over cotton carboxymethylated fibers (CMCs) through a friendly environmental insitu method. SEM and XRD analyses showed that MOFs uniformly anchored on cotton fibers were resistant to sterilization by autoclaving processes.
On the other hand, using the ASTM E2149-13a method, it was observed that all the MOF systems exhibited antibacterial activity against Escherichia coli ATCC25922TM, Staphylococcus aureus ATCCR6538TM and Klebsiella pneumoniae ATCCR13882TM. In general, Gram-negative bacteria were the most susceptible to the cellulose-MOF systems; in fact, the cotton-Cu-MOF (MOF-199) displayed antimicrobial activity greater than 99% against Gram-negative bacteria in less than 5 min. On the other hand, the cotton-Zn-MOFs (MOF-74 and MOF-5) systems inhibited the growth of E. coli and K. pneumonia, displaying a bacterial growth inhibition range between 80% and 99.9%. In addition, the cotton-Al-MOF (MIL-53) exhibited a greater spectrum of antibacterial activity, indeed inhibited the growth of S. aureus (Gram-positive), K. pneumoniae, and E. coli (Gram-negative) at 50.2%, 53.6%, and 93.4%, respectively. Noteworthy, the antibacterial activity of Al+3 based MOFs has not been reported previously. All these results expand the potential of cellulose-MOF systems as attractive materials in the production of antibacterial fabrics, especially for hospital environments.
Cotton and its blended fabrics are widely used textile materials in daily life; however, their high flammability brings serious fire hazards. It remains a huge challenge to endow cotton and its ...blended fabrics through simple and universal technology. In this work, a novel water-based polyelectrolyte complex (PEC) coating was developed from chitosan and a water treatment agent (amino trimethylphosphonic acid). By controlling the degree of ion pair aggregation through pH adjustment, the intumescent and stable PEC coating can be constructed quickly via facile blading coating and curing processes. High transparency allows for the deposition of the coating with little effect on the original pattern of the coated fabric. Additionally, when the coated fabrics were exposed to flame, the PEC coating underwent a quick self-char-forming reaction in advance and formed a protective char layer covered on the fibers. Thus, the PEC coating with low adding-on (11.5–21.5 wt %) shows universally high flame retardancy for cotton, polyester/cotton blends, and polyester/poly(vinyl alcohol)/cotton blends. The coated fabrics show excellent extinguishing performances, high limiting oxygen index values of 27.5%–28.5%, and total release smoke inhibition of 42%. This work provides a promising universal technology for manufacturing fire-safety cotton and its blends in a simple and eco-friendly way.
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•A facile method of preparing nano-silver conductive ink was proposed.•It was printed on cotton fabric when sintering at 60°C for 30min..•The highest conductivity is 2×10−5Ωm with the ...silver content 30wt%.
Monodisperse silver nanoparticles conductive ink was successfully synthesized by in-situ synthesis method in an aqueous solution. The size distribution of the Ag nanoparticles was tested and the average diameter was within 10nm. A spontaneous coalescence and sintering of Ag NPs at 60°C for 30min was realized in the presence of hydrogen chloride. The interface bonding between dispersant and silver nanoparticles was investigated by XRD and FTIR. The conductive ink doped with polyaniline has a good adhesion to cotton surface and better conductivity. The highest conductivity was 2×10−5Ωm when the silver content was 30wt.%. This prepared conductive ink could be printed on cotton fabric to form conductive circuits and the conductivity can remain at least 30days. These promising results suggest applications of printed electronics devices using textiles as substrates.
The novel coronavirus pandemic (COVID-19) has necessitated a global increase in the use of face masks to limit the airborne spread of the virus. The global demand for personal protective equipment ...has at times led to shortages of face masks for the public, therefore makeshift masks have become commonplace. The severe acute respiratory syndrome caused by coronavirus-2 (SARS-CoV-2) has a spherical particle size of ~97 nm. However, the airborne transmission of this virus requires the expulsion of droplets, typically ~0.6-500 µm in diameter (by coughing, sneezing, breathing, and talking). In this paper, we propose a face covering that has been designed to effectively capture SARS-CoV-2 whilst providing uncompromised comfort and breathability for the wearer. Herein, we describe a material approach that uses amorphous silica microspheres attached to cotton fibres to capture bioaerosols, including SARS CoV-2. This has been demonstrated for the capture of aerosolised proteins (cytochrome c, myoglobin, ubiquitin, bovine serum albumin) and aerosolised inactivated SARS CoV-2, showing average filtration efficiencies of ~93% with minimal impact on breathability.
Powell, however, desires not only to make an addition but also a correction, providing evidence that, he argues, refutes or qualifies two long-standing assumptions: one, that before the Civil War ...began, the cotton industry was threatened by a crisis of overproduction that would have reduced factory work irrespective of the war; and two, that Liverpool was eager to see trade with the South resume and was thus a hotbed of pro-Confederacy sentiment. For Powell, this means that the enormous surplus from 1860 to 1861 could never have developed into a crisis of overproduction. Since the Indian and Chinese markets expanded in the late 1850s, he argues, there is no reason to doubt their capacity for expansion, despite the fact noted by Henderson that both countries' demand had surged because of the end of the Indian Rebellion and the Second Opium War and was thus likely to plateau. The problem is that Beckert's actual argument is less about the collusion between private actors in this sense, as it is about the interlocking of larger patterns in economic development and the actions and policies of states, which made slavery in one part of the world the basis for the accumulation of wealth in another part of the world where slavery was technically illegal.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The synthesis of multi-function flame retardants is widely increasing to fulfill industrial and economic goals. In this work, a novel flame retardant, melamine salt of tannic phosphate (MTP) was ...prepared and characterized. MTP was mixed with polyvinyl alcohol (PVA) solution and used as a coating for cotton fabrics. In addition, tannic acid (TA) and melamine phosphate (MP) were mixed with PVA solution and applied as a coating for cotton fabrics. Vertical and horizontal flammability tests showed that the flame did not propagate in samples treated with PVA/MTP. In contrast, samples treated with PVA/TA/MP burnt completely. Limiting oxygen index (LOI) data indicated that samples treated with PVA/30%MTP reached LOI value 68.4%, while the control sample had LOI value 17.1%. Smoke density results presented that PVA/MTP succeeded in reducing the maximum specific optical density (Ds
max
) of cotton fabrics. FTIR gas analyzer results manifested that the addition of PVA/MTP to cotton fabrics decreased the emission of CO, CO
2
, C
3
H
8
, C
2
H
6
, C
6
H
14
, and formaldehyde in the gas phase. Fractional effective dose (FED) and lethal toxic potency (LC
50
) showed that samples coated with PVA/MTP are less toxic than blank. In addition, these fabrics exhibited a remarkable antibacterial property against gram-positive and gram-negative bacteria.
