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Flame Retardance of Fabrics
Published in Menachem Lewin, Stephen B. Sello, Handbook of Fiber Science and Technology: Chemical Processing of Fibers and Fabrics, 2018
An oligomeric vinyl phosphonate finish, Fyrol 76, was developed by Eisenberg and Weil [296] and its major difference from the other finishes is that it is cured (made insoluble) by a free radical mechanism. The formula of Fyrol 76 is given as [299] : Fyrol 76 is water soluble, contains 22.5% P, and is used with methylol-acrylamide and a free-radical catalyst, e.g., persulfate, by a conventional pad-dry-cure-wash procedure with little odor in the plant. Cure temperatures are in the range of 150–175°C. About 25–30% total add-on is needed for light-weight cotton flannel to pass the DOC FF-3-71 standard. It is claimed that the hand of the fabrics is soft, tearing-strength retentions are approximately 65%, and bursting-strength retentions on knits are 60–80%. The fabrics exhibit wrinkle recovery and durable-press properties [166]. The process has been demonstrated on cotton flannel, knits, printed cloth, sheeting, terry cloth, corduroy, heavy-weight fabrics for tenting [299], cotton-rayon blends, 100% rayon, and a number of cotton-PET blends [298]. Fyrol 76 has been applied to cotton-PET blends with the acrylamide or TMM coreactant. Bromine derivatives have also been added [166].
P
Published in Splinter Robert, Illustrated Encyclopedia of Applied and Engineering Physics, 2017
[general] Net charge with value that has opposite sign of the charge of an electron; alternatively, with a charge that repels protons. Charge is quantized, on an atomic level by proton value and as a material based on the amount of missing electrons with respect to a neutral electric state. An object made from glass that is rubbed with silk or flannel will become positively charged, transferring electrons from the glass to the cloth. The existence of charges can be dated back to the rubbing of amber with fur, as described by Plato (427–347 BC). The nomenclature of positive and negative charge (introducing the hypothesis that there are only two types of charges) was introduced by the scientist and statesman (founding father) from the United States Benjamin Franklin (1706–1790), and was based on the presumed transfer of positive charge, later found to be a misinterpretation. Franklin’s proposition was based on the observations by the scientist and astronomer from Great Britain Stephen Gray (1666–1736) in 1730.
Personal Protective Equipment (PPE) and Decontamination for Terrorist Agents
Published in Robert A. Burke, Counter-Terrorism for Emergency Responders, 2017
Gross patient decontamination is performed with minimal equipment, products, or implements, and can be set up quickly. Examples include the Ladder Pipe Decontamination System to provide a high-volume, low-pressure water shower from fire apparatus and spot decontamination using a product such as Reactive Skin Decontamination Lotion. Time is critical in order to save the most lives.The immediate removal of clothing outside the contaminated area for patients who have been visibly contaminated or who have been suspected of having been contaminated.Processing the victims through a high-volume, low-pressure water shower (∼50–60 psi) is priority. This may aid in the removal of 80%–90% of physical contamination in almost all cases.Provide effective mass casualty decontamination. Other activities as setting up commercial decontamination tents, tarps, additional decontamination equipment, and/ or creating a soap–water solution should be accomplished when time permits.Conduct decontamination triage prior to administering a high-volume, low-pressure water shower.When the contamination involves chemical vapors, biological or radiological material, using gentle friction (such as rubbing with hands, cotton flannel or microfiber cloth, or sponges) is recommended to aid in removal of contamination. Rubbing should start with the head and proceed down the body to the feet. Extra care should be taken to prevent the spread of contamination to the mouth, nose, and eyes (such as holding one's breath to avoid inhalation/close contact with mucosa and closing one's eyes while wiping the face and head).
Development of reusable cloth mask with nanoparticle filtration efficiency greater than 95%
Published in Aerosol Science and Technology, 2022
Maryam Ebrahimiazar, Ladan Eskandarian, Samuele Amadio, Andre Khayat, Nasser Ashgriz, Milad Alizadeh-Meghrazi
The main purpose of this research is to develop a cloth mask which has the necessary filtration efficiency at reasonable pressure drop and is reusable and washable. Previous works were mostly focused on the sample filtration with a minimal study on the impact of laundering. The study of Neupane et al. (2019) has shown a 20% filtration efficiency drop for cloth masks after only 4 wash cycles. This was reported to be mainly due to the change in the sample pore size and shape. The comprehensive study of Bhattacharjee et al. (2021) showed that after 2 wash cycles of 15 min at 60 °C, the filtration efficiency of cotton and polyester masks improved while no significant change was noticed for nylon, linen, silk, and towel cloth masks. The improvement in the filtration efficiency was explained by consolidation and shrinkage of the samples and the subsequent decrease in samples’ tightness and porosity. Krishan et al. (2021), however, compared the filtration of hand-washed cotton masks with commercial detergent and reported a very little change in the sample’s properties and filtration properties even after 70 cycles. Hao, Xu, and Wang (2021) studied the effect of wash-dry cycles (1, 5, and 10 cycles) on the performance of flannel, bamboo, velvet, jersey, silk, cotton, and muslin masks. The results suggested that wash-dry cycles do not have an obvious impact on the performance of fabric masks, with even a slight improvement in the filtration efficiency of flannel, bamboo, and cotton samples.
Factors influencing the filtration performance of homemade face masks
Published in Journal of Occupational and Environmental Hygiene, 2021
Weixing Hao, Guang Xu, Yang Wang
A wide range of common household materials were evaluated, including five types of paper materials and 16 types of fabric materials (Table 1). The results were compared against the surgical mask (earloop, ASTM F2100-19 Level 1) material. In addition to the information of the tested and common materials, Table 1 also lists the grams per square meter (GSM), filtration efficiency (FE) particle size of 0.3 μm, overall FE particle sizes, flow resistance (), and filter quality (). In this study, GSM was evaluated as an indicator for material filtration performance because it correlates with the thickness and packing density of the garment. The particle size of 0.3 μm is essential, because it is within the most penetrating particle size (MPPS) and it is used as an indicator for the filtration performance in similar studies (Podgorski et al. 2006). It is possible that the virus-containing aerosols may penetrate the materials within this size window and further transmit through the human respiratory system. However, it should be noted MPPS is also affected by many factors such as flow rate and particle charge (Rengasamy et al. 2012). Moreover, the microstructure of the materials in this study was observed. Eight fabric materials: microfiber, flannel, bamboo, velvet, jersey, silk, cotton, and muslin materials, were further examined in the effect of washing and drying cycles. The decay of triboelectric charging of polypropylene fabrics was also discussed.
Questioning cloth breathability in “Designing better cloth masks”
Published in Journal of Occupational and Environmental Hygiene, 2023
High-efficiency natural cloth has shown unsatisfactory breathability across many studies, with contrary claims sometimes arising from methodological or interpretive errors (e.g., Konda et al. 2020; for a review, see Kwong et al. 2021). In a recent example, Mumma et al. (2023) claimed that “three layers of 100% cotton flannel or twill offer high filtration efficiencies and acceptable breathability…even after repeated washing and drying.” The claim reflects a misunderstanding of ASTM F3502 Standard Specification for Barrier Face Coverings used as the breathability benchmark.