This study presents the investigation of the electromagnetic properties and resistance performance of electrically conductive fabrics coated with composition containing the conjugated polymer system poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS). The developed fabrics were intended for electromagnetic radiation (EMR) shielding in microwave range and for absorbing microwaves in radar operating range, so as to act as radar absorbing materials (RAM). The measurements of reflection and transmission of the developed fabrics were performed in a frequency range of 2–18 GHz, which covers the defined frequencies relevant to the application. Four types of fabrics with different fiber composition (polyamide; polyamide/cotton; wool and para-aramid/viscose) were selected and coated with conductive paste using screen printing method. It was found that EMR shielding effectiveness (SE) as well as absorption properties depend not only the amount of conductive paste topped on the fabric, but also resides in the construction parameters of fabrics. Depending on such fabric structural parameters as density, mass per unit area, type of weave, a layer of shield (or coating) just sticks on the fabric surface or penetrates into fabric, changing the shield thickness and herewith turning SE results. Meanwhile, the fiber composition of fabrics influences mostly bonding between fibers and polymer coating. To improve the resistance performance of the developed samples, a conventional textile surface modification technique, atmospheric plasma treatment, was applied. Initially, before plasma treatment and after treatment the fabrics were evaluated regarding an aqueous liquid repellency test, measuring the contact angles for the water solvent. The influence of plasma treatment on resistance performance of coated fabrics was evaluated by subjecting the plasma treated samples and untreated samples to abrasion in the Martindale abrasion apparatus and to multiplex washing cycles. These investigations revealed that applied plasma treatment visibly improved abrasion resistance as a result of better adhesion of the coating. However, washing resistance increased not so considerably.
Recently, society has been experiencing an increase of the level of electromagnetic exposure, especially in the radiofrequency range. This issue is an outcome of all technologies that make use of such radiation to meet the human need for faster communication processes. For instance, 5G wireless technologies are now emerging throughout the world that will require electromagnetic waves of higher frequencies (up to 30 GHz) and more base stations (expected to be 60 times higher than the current number of 4G base stations) that will be placed closer to each other. [1] In addition, other technologies such as GPS, radar, and mobile phones are available that use radiofrequency electromagnetic radiation, thus actively contributing to all this undesired electromagnetic exposure. This excessive radiation may lead to malfunctions in the human health or affect the operation of surrounding electronic equipment. [2] Since it is not practical to diminish the electromagnetic (EM) radiation utilization because it is needed for all the abovementioned applications, the most straightforward strategy to reduce its impact is by recurring to electromagnetic interference (EMI) shielding.EMI shielding refers to the use of a screen/shield to attenuate or even eliminate the electromagnetic radiation in a desired space. The attenuation ability of a shield is quantified by the shielding effectiveness (SE), in dB. The EMI shielding is related
Opuntia ficus-indica is a cactus species that has a large potential in several applications. Despite its enormous potential, the production process is still a concern. The harvest process is still mostly manual and implies a dangerous exposure of the human being not only to harsh environmental conditions such as high temperatures but also to the big and resistant spines of the Opuntia ficus-indica. To fulfill the lack of suitable protection equipment for this specific activity, emerged a project with the aim of producing an innovative clothing system composed by textile structures that can act as a barrier to spines and glochids without compromising breathability and presenting a suitable fitting, ergonomics and freedom of movements. This paper will focus on the development of a multilayer clothing system in which the outer layer provide protection against perforation and the inner layer acts like a second skin providing thermal comfort and freedom of movement, so the producers can withstand high temperatures. Concerning the inner layer, several textile structures were developed to analyze the impact on breathability, moisture management and thermal regulation. For the outer layer more than 20 fabrics were developed and submitted to laboratory tests to study their perforation and tearing resistance (according to EN 388).Afterward two structures were selected to proceed and new finishing’s were developed to prevent the adhesion of the glochids to the textile substrate and simultaneously to give water repellency. Results achieved for the clothing solution from laboratory and field tests with end-users, will be presented.
The continuous research and development regarding firefighters’ personal protective equipment (PPE) has led to significant improvements in recent decades. Despite the evolution of firefighters’ PPE, every year an undesirable number of firefighters are seriously burned during firefighting operations, with some of them eventually losing their lives. The protection given by firefighters’ PPE can be further increased with the incorporation of smart textiles in the personal protective equipment, namely, wearable electronics (i.e., integrated sensors to monitor diverse parameters: heart rate, oxygen saturation, carbon dioxide detector, and setting real-time communication with a command post) and advanced materials such as phase change materials (PCMs). The evolution of firefighters’ PPE has been followed by an evolution and update in the international and national standards that specify performance requirements for firefighters’ protective clothing for structural and wildland firefighting as well as technical rescue. This study will focus on the analysis of firefighters protective clothing evolution regarding the use and integration of advanced smart materials, namely, phase change materials, taking into consideration the evolution and requirements of international and European standards as well as national legislation for firefighters’ protective clothing.
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