Characterizing Steam Penetration through Thermal Protective Fabric Materials

This study performs an analysis of steam penetration through thermal protective fabric materials. Different, multilayered thermal protective fabrics were selected and tested in a laboratory-simulated steam exposure, and their steam protective performance (SPP) was measured in terms of the time required to generate second-degree burns on the bodies of wearers. Additionally, the total transmitted thermal energy (TTTE) through the fabrics during testing was measured. Through statistical analysis, it was established that fabric properties, namely air permeability and thickness, are the key factors that affect the SPP and TTTE; the relationship among the fabric properties, SPP, and TTTE is also summarized. Theoretically, it has been found that heat and mass (steam) transfer occur through fabrics in the course of steam exposure, which mainly affect the SPP and TTTE. This study could help textile/materials engineers to develop high performance thermal protective fabrics for the increased occupational health and safety of firefighters and industrial workers.

Failure Investigation of Layered LFT SB1plus Package after Ballistic Tests for Level IIA

The main objective of this study focuses on designing and testing body protection systems using advanced materials based on aramid fibers, for high impact speeds of up to 420 ± 10 m/s. Ballistic applications of aramid fiber-based composites mostly include soft body armors. The investigation of the failure mechanisms identifies issues of protective fabrics, major challenges and technological problems for efficient development of these systems. The authors present an investigation on the failure processes and destructive stages of a ballistic package made of successive layers of LFT SB1plus, a trade name for a multiaxial fabric by Twaron Laminated Fabric Technology (LFT), taking into account the particular test conditions from NIJ Standard-0101.06 Ballistic Resistance of Body Armor. The main parameter of interest was the backface signature (BFS), but also details of projectile arrest and SEM investigation could offer arguments for using this material for individual protection. For the reported tests, the maximum and minimum values for BFS were 12 mm and 24 mm, the mean value being 18.66 mm and the standard deviation being 3.8 mm.

Mathematical model used for predicting arc-flash protective performance of fabrics based on physical parameters

In this study, parameters that may affect the performance of arc-flash protective fabrics were systematically analyzed. Sixteen different commonly used fabrics with different configurations and grammage were produced and investigated, namely four raw materials with different configurations (93:0:5:2, 70:23:5:2, 46:47:5:2, and 23:70:5:2) and four with different grammage (180, 210, 240, and 270 g/m2). It was found that factors had different effects on the arc protective performance. Principal component analysis showed that the four plain weave fabrics of 180 g/m2 behaved differently compared with other samples, which was ascribed to the related differences in weave structure. In addition, a predicting mathematical model was developed based on the parameters that have the greatest influence on arc protective performance. The prediction parameters were not added to the structure, but replaced with physical parameters such as air permeability and thermomechanical properties. The adjusted R2 was 0.867, which demonstrated the rationality of using multiple linear regression to accurately predict arc protective performance. It was hypothesized that the construction of the mathematical model could contribute to the arc protective fabric evaluation and future researches in this field.

The Impact of Biodegradable Geotextiles on the Effect of Sodding of Difficult Terrain

Difficult terrain is characterized by deteriorated conditions for plant adaptation, e.g., owing to poor substrate, substantial land slope, or intensive insolation. In terms of plant adaptation, difficult terrain includes newly created ski slopes, any kind of embankment, scarps, levees, and etc. Application of grasses is an effective and economic method of stabilization of the ground. However, sowing of grass-legume mixtures to sod these areas does not typically produce adequate effects. Application of a new generation of protective fabrics with the addition of bird feathers may be a remedy to these problems. The aim of this study was to evaluate the applicability of biodegradable fabrics for covering difficult areas to improve the habitat conditions for plants. To evaluate this issue, an area characterized by difficult conditions for plant development was selected. Five types of protective fabrics were applied. The main factor influencing the efficiency of the sodding of difficult terrain was the application of fabrics that were capable of absorbing water, which were then given to plants over a longer period of time. Vegetation grew easiest through the geotextile made of sheep wool with the addition of bird feathers. Fabrics manufactured from problematic waste materials contribute to an ecological effect as well as an economic effect resulting from lower costs of waste management as well as the income from selling the innovative product.

Analysis of woven fabric behavior under punching force

In several applications, the industrial and protective fabrics might be subjected to punching by the rigid sharp spikes. Fabric resistance to the penetration of the puncher at a constant rate was studied. The analysis of the factors influencing the resistance of the fabric and an explanation of the puncture mechanism were generated. Punching force-displacement curves were obtained and four noticeable fabric failure modes were observed. A special setup was designed so that the fabric sample can be subjected to the biaxial stresses during the puncture tests. This paper studies the puncture behaviors of the plain, twill 1/3, and twill 2/2 woven fabric designs. It was found that the increase in the number of fabric layers from one to three and the number of picks/cm from 17.6 to 27.2 would elevate the punching resistance and the punching energy by 354% and 333%, respectively, with the insignificant change in the values of specific punching force and energy. Plain weave design proved to have higher values than twill design. A high correlation was observed between fabric tensile strength, fabric Young’s modulus, fabric failure energy and its punching force and punching energy.

Photochromic Dyes for Smart Textiles

Photochromism is a light induced reversible color change phenomenon in photochromic molecule due to light and heat effect and molecular species exist in two forms which have different absorption spectra. The fascinating color change by photochromic molecules in response to specific wavelength of light produces number of applications such as U.V. protective fabrics, ophthalmic photochromic lenses, optical data storing, optical switch, sensors and display. This chapter provides a brief and conclusive review of photochromism their mechanism and application in Textiles. Although photochromic materials are in use since 1960 in lenses and sunglasses, but the development is slow due to technical difficulties and poor commercial application. Now there is renewed interest in photochromic materials which are used in nanofibers in smart textiles and in allied items.

Development of apparatus to evaluate cutting resistance of protective fabrics

In recent decades, attention has been focused on the design of protective soft fabrics against cutting. The anticipated textiles should shield the wearer's body from threats caused by pointed or sharp-edged objects, such as a knife, sharp blade, or spike. Therefore, as it is of great importance to design slash-resistant fabrics, it is also necessary to have an apparatus that gives the possibility to simulate the conditions of cutting processes of the protective fabric. The main objective of the present work is to develop a new apparatus to test the slash-proof materials used in soft protective armor or gloves. The apparatus can test the material with different cutting angles, different speeds, and various normal forces applied to the sample at the point of contact between the material and the cutting blade, with the capability to change all the parameters affecting the cutting force. This study aims to develop a cutting apparatus to study the cutting mechanism of textile materials with the capability to change all the parameters affecting the cutting force. The cutting angle and cutting speed have a significant effect on the maximum cutting force; however, the latter showed a high decrease of the maximum cutting force.

Characterization and modeling of thermal protective fabrics under Molotov cocktail exposure

This study aims to characterize and model the thermal protective fabrics usually used in workwear under Molotov cocktail exposure. Physical properties of the fabrics were measured; and, thermal protective performances of the fabrics were evaluated under a fire exposure generated from the laboratory-simulated Molotov cocktail. The performance was calculated in terms of the amount of thermal energy transmitted through the fabrics; additionally, the time required to generate a second-degree burn on wearers’ bodies was predicted from the calculated transmitted thermal energy. For the characterization, the parameters that affected the protective performance were identified and discussed with regards to the theory of heat and mass transfer. The relationships between the properties of the fabric systems and the protective performances were statistically analyzed. The significant fabric properties affecting the performance were further employed in the empirical modeling techniques − Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) for predicting the protective performance. The Coefficient of Determination (R2) and Root Mean Square Error (RMSE) of the developed MLR and ANN models were also compared to identify the best-fit model for predicting the protective performance. This study found that thermal resistance and evaporative resistance are two significant properties (P-Values < 0.05) that negatively affect the transmitted thermal energy through the fabric systems. Also, R2 and RMSE values of ANN model were much higher (R2 = 0.94) and lower (RMSE = 37.42), respectively, than MLR model (R2 = 0.73; RMSE = 191.38); therefore, ANN is the best-fit model to predict the protective performance. In summary, this study could build an in-depth understanding of the parameters that can affect the protective performance of fabrics used in the workwear of high-risk sectors employees and would provide them better occupational health and safety.

Boron Nitride Nanotubes Enhance Mechanical Properties of Fibers from Nanotube/Polyvinyl Alcohol Dispersions

Effectively translating the promising properties of boron nitride nanotubes (BNNTs) into macroscopic assemblies has vast potential for applications, such as thermal management materials and protective fabrics against hazardous environment. We...