ABSTRACT
The purpose of fabric masks in the prevention of the spread of COVID-19 often requires that the masks be worn for extended periods without removal. The management of the conditions in the micro-climate inside the masks is important to keep the wearer comfortable and enhance user compliance. In this study, the effect of mask design and fabric type on the micro-climate was investigated using thermocron iButtons to record the temperature and humidity inside the masks. It was found that the mask style, and its effect on the amount of air incorporated in the micro-climate, had a significant influence on the factors that determine the temperature and humidity levels. In the shaped masks, the impact of the mask design on the results was stronger than the effect of fabric type. In the folded masks that fit snugly around the face, the effect of fabric type was significant, and both fibre composition and fabric structure contributed to the differences in the performance of the three fabrics tested. In the case of the masks with an inserted filter, a significant amount of trapped still air in the fabric layers and the increased mask stiffness had the strongest effect on the temperature and humidity inside the masks. Significant differences were also found in the temperatures recorded in the different time segments, highlighting the importance of conducting comfort evaluations over a long enough time to prevent false interpretations. The results of this study emphasize the importance of considering all the components of mask design, namely style, fibre type, and fabric structure, in the development of masks to enhance user compliance.
ABSTRACT
To function as source control, a fabric mask must be able to filter micro-droplets (≥5 µm) in expiratory secretions and still allow the wearer to breathe normally. This study investigated the effects of fabric structural properties on the filtration efficiency (FE) and air permeability (AP) of a range of textile fabrics, using a new method to measure the filtration of particles in the described conditions. The FE improved significantly when the number of layers increased. The FE of the woven fabrics was generally higher, but double-layer weft knitted fabrics, especially when combined with a third (filter) layer, provided a comparable FE without compromising on breathability. This also confirmed the potential of nonwoven fabrics as filter layers in masks. None of the physical fabric properties studied affected FE significantly more than the others. The variance in results achieved within the sample groups show that the overall performance properties of each textile fabric are a product of its combined physical or structural properties, and assumptions that fabrics which appear to be similar will exhibit the same performance properties cannot be made. The combination of layers of fabric in the design of a mask further contributes to the product performance.
ABSTRACT
COVID-19, classified as SARS-CoV-2, is causing an ongoing global pandemic. The pandemic has resulted in the loss of lives and has caused economic hardships. Most of the devices used to protect against the transmission of the novel COVID-19 disease are related to textile structures. Hence, the challenge for textile professionals is to design and develop suitable textile structures with multiple functionalities for capturing viruses, passivating them, and, at the same time, having no adverse effects on humans during the complete period of use. In addition to manufacturing efficient, biocompatible, and cost-effective protective face masks, it is also necessary to inform the public about the benefits and risks of protective face mask materials. The purpose of this article is to address the concerns of efficiency and efficacy of face masks by primarily reviewing the literature of research conducted at the Technical University of Liberec. The main focus is on the presentation of problems related to the specification of aims of face mask applications, mechanisms of capture, durability, and modes of sterilization. The recommendations, instead of conclusions, are addressed to the whole textile society because they should be leading players in the design, creation, and proper treatment of face masks due to their familiarity with the complex behavior of textile structures and targeted changes of structural hierarchy starting from polymeric chains (nano-level) and ending in planar textile structures (millimeter level) due to action by mechanical, physical and chemical fields. This becomes extremely critical to saving hundreds of thousands of lives from COVID-19.
ABSTRACT
High filtration performance and antibacterial property have been the main concerns of air filters. In this work, the silver nanoparticles (AgNPs) were produced by liquid phase reduction method and were added into polyvinylidene fluoride (PVDF) solutions at a ratio of 0.2%, 0.4%, 0.6%, 0.8%, and 1% for electrospinning. Nanofibers with the tree-like structure were fabricated by controlling the processing parameters. Therefore, a tree-like AgNPs/PVDF nanofiber membrane containing AgNPs was successfully developed. The AgNPs solutions were analyzed by UV-vis absorption spectrum to determine the size of AgNPs, and the nanofiber membranes were also evaluated in terms of morphology, structure, hydrophobic property, filtration performance, and antibacterial property. The results showed that the size of AgNPs was approximately 10 nm, the average diameters of branch-like fibers and stem-like fibers were about 30.8 nm and between 90 nm with 140 nm, respectively. The addition of AgNPs did not change the hydrophobic property of the PVDF nanofiber membrane;the filtration efficiency of AgNPs/PVDF nanofiber membrane was 99.95 ∼ 99.97% and the lowest pressure drop was 137.5 Pa;the bacterial reduction rates (BR) value against for S.aureus and E.coli were kept at a level of higher than 99.6% after exposure to sunlight for two weeks. Therefore, a kind of air filter with high filtration performance and durable antibacterial property was successfully developed by adding AgNPs and by creating tree-like structure fibers.