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This study aims to evaluate the dyeing of the p-aramid fibre with cationic dyes and investigate the effect of dyeing in the protection of the fibre from ultraviolet (UV) light.

P-aramid fabric has been dyed with cationic dyes using benzyl alcohol as swelling agent to promote the penetration of dye molecules into the fibre. The fabrics were evaluated against colour strength (K/S) value and colour fastness properties after dyed with cationic dyes using full factorial design. This design was used to study the effect of factors that affect the response variables as well as to study the interactions among the factors on response variable. The bursting strength, scanning electron microscopy analysis and X-ray diffraction analysis of undyed and dyed p-aramid fabric were performed before and after exposure to UV light to investigate the changes in mechanical behaviour.

The results show that the p-aramid fabric dyed with cationic dyes has good K/S values and good fastness properties. The exposure of undyed p-aramid fabric to UV light causes serious loss in strength over short duration i.e. 40 h. Dyeing of p-aramid fabric enhances the resistance to UV light which reduces the loss in strength.

Most of the work is patented and no one has done the process optimization for the industry, so this study offers promising outcomes concerning the dyeing of p-aramid fabric with enhanced shade depth and good colour fastness characteristics.

PBO and p-aramids fibers were compared on thermal degradation in TG and DTG experiments, and PBO fiber showed the highest degradation temperature in both air and nitrogen atmosphere. Annealed under high temperature of 100°C, 200°C, 300°C and 400°C for 1.5 hours, the tenacity of these samples all decreased with the temperature, while PBO fiber showed the best tensile retention property. Whereas using the xenon arc light to simulate sunlight irradiated on the PBO and Kevlar samples for different time respectively, PBO showed the worst tensile retention property. In contrast, the p-aramid fibers showed their relatively good mechanical stability when exposed to the simulated sunlight. Therefore, the application of PBO fibers should be careful in the state of sunlight irradiation although PBO has the highest original mechanical and thermal property.

This paper outlines the innovations in high functional and high performance fibres for applications in protective clothing, including fibres for flame and heat protection. It also describes some typical woven and non‐woven constructions for such applications. And presents the trends in producing smart textile materials, capable of interacting with human/environmental conditions.

This study aims to analyse the variations of thermal comfort inside a building space by using different curtains.

Phase change materials (PCMs) such as wax, sand and mixture of sand and wax were used with cotton curtain to compare the results of PCM curtains with the performance of normal cotton curtain against constant heat exposure. Heat exposure was provided with halogen to simulate the solar radiation. Further simulation was performed on ANSYS and experimental results were compared with the simulation results. In addition to this, the results were analysed for optimized performance by calculation root mean square error.

It was found that PCM used curtains that have better performance than normal curtain. Furthermore, sand curtain was proved as the best curtain and mixture of sand and wax curtain could replace the sand curtain where there is limitation of weight; also, there was less error between experimental and simulation was reported for sand curtain as compare to other curtains.

Layers of different PCMs were used before cotton curtain and in modelling assumptions such as one-dimensional heat transfer, uniform thermal conductivity.

To the best of the authors’ knowledge, there is no such study that was performed earlier.

Firefighter Personal Protective Equipment (PPE) is the only barrier between the firefighter and hazardous environment. Gloves are a crucial component of the multi-component PPE. Over time the gloves have reduced the intensity of hand injuries, yet further improvement in terms of material selection and glove design is required to strike the balance between protection and comfort. Focusing on the material aspect, the purpose of this study is to present literature analysis on material selection and testing for firefighter gloves.

The study conducted a literature analysis on material selection and characterization of firefighter PPE. The review summarizes and evaluates past work addressing the characterization of firefighter gloves in accordance with NFPA 1971 requirements and points out found research gaps to aid with foundation of future research.

The study summarizes several research works to inform readers about the material selection and characterization of firefighter gloves. Based on the analyzed literature, the study resulted in material specification sheets for firefighter gloves. The developed material specification sheets provide information in terms of crucial material properties to be incorporated for accurate functioning of firefighter gloves, testing methods to validate those material properties and materials from analyzed literature exhibiting desired properties.

With large research addressing firefighter PPE, only limited studies focus specifically on gloves. Thus, this study provides a literature analysis covering material selection and testing for gloves. A consolidated firefighter gloves material specification document, which does not appear to be available in the literature, will provide a foundation for the development and characterization of firefighter gloves to better serve the functions along with ensuring user comfort.

Stab-resistant body armor (SRBA) can protect the human body from injury as a result of stabbing by sharp projectiles. However, in its current design SRBA, it has not been widely adopted for use, because of its weight and poor flexibility. Herein, this paper aims to detail a new type of SRBA that is inspired by the armor plating of mammals and is fabricated using laser sintering (LS) technology.

This new type of SRBA was fabricated using LS technology. The laser sintered SRBA was subjected to a stab resistance performance test that conformed to the GA 68-2008 Chinese National Standard. The stab resistance response of the novel structured, stab resistance test plates in this study was analyzed using the using the AUTODYN explicit module in ANSYS-Workbench.

The structure of the novel stab resistance plate was designed and the optimum structural parameters were tested, discussed and achieved. The mechanism of dissipation of the impact energy by the pyramidal structures of the novel SRBA was studied, and it was found that this structure dispersed the kinetic energy of the knife and minimized the structural damage to the plate. Interlinks inspired by the pangolin hierarchy structure were designed and used to fabricate a large piece of laser sintered body armor.

High-performance laser sintered stab resistance plate was produced via the material and structure studies, which could reduce 40 per cent weight on the stab resistance body armor and increase the wearability.

Composite laminates are considered one of the most popular damage-resistant materials when exposed to impact force in civil and military applications. In this study, a comparison of composites 12 and 20 layers of fabrics Kevlar and ultrahigh-molecular-weight poly ethylene (UHMWPE)-reinforced epoxy under low-velocity impacts represented by drop-weight impact and Izod pendulum impact has been done. During the Izod test, Kevlar-based composite showed damage at the composite center and fiber breakages. Whereas delamination was observed for UHMWPE reinforced epoxy (PE). The maximum impact strength was for Kevlar-reinforced epoxy (KE) and increases with the number of laminates. Drop-weight impact test showed the highest absorbed energy for (KE) composites. The results revealed that different behavior during the impact test for composites belongs to the impact mechanism in each test.

Aramid 1414 Kevlar 49 and UHMWPE woven fabrics were purchased from Yixing Huaheng High-Performance Fiber Textile Co. Ltd, with specifications listed in Table 1. Epoxy resin (Sikafloor-156) is supplied from Sika AG. Sikafloor-156 is a two-part, low-viscosity, solvent-free epoxy resin, with compressive strength ∼95 N/mm², flexural strength ∼30 N/mm² and shore D hardness 83 (seven days). The mixture ratio of A/B was one-third volume ratio. Two types of laminated composites with different layers 12 and 20 were prepared by hand layup: Kevlar–epoxy and UHMWPE–epoxy composites as shown in Figure 1. Mechanical pressure was applied to remove bubbles and excess resin for 24 h. The composites were left in room temperature for seven days, and then composite plates were cut for the desired dimensions. Low-velocity impact testing, drop-weight impact, drop tower impact system INSTRON CEAST 9350 (see Figure 2) was facilitated to investigate impact resistance of composites according to ASTM D7137M (Test Method for Compressive, 2005). Low-velocity impact tests have been performed at room temperature for composite with dimensions 10 × 15 cm² utilizing a drop tower (steel indenter diameter 19.85 mm as shown in Figure 3), height (800 mm), drop mass (5 kg) and speed (3.96 m/s). Special impact equipment consisting of vertically falling impactor was used in the test. The energy is obtained from Drop tower impact systems, (2009) E = ½ mv² (2.1). The relationship between force–time, deformation–time and energy–time and deformation was obtained. Energy–deformation and force–deformation relationships were also obtained. The depth of penetration and the radius of impactor traces were recorded. Izod pendulum impact test of plastics was applied according to ASTM D256 (Test Method for Compressive, 2005). Absorbed energy was recorded to compute the impact strength of the specimen. The specimen before the test is shown in Figure 4.

In order to investigate two types of impact: drop-weight impact and Izod impact on damage resistance of composites, the two tests were done. Drop-weight impact is dropping a known weight and height in a vertical direction with free fall, absorbed energy can be calculated. Izod impact measures the energy required to break a specimen by striking a specific size bar with a pendulum (Test Method for Compressive, 2005; Test Methods for Determining, 2018). The results obtained with the impact test are presented. Figure 5 shows the histogram bars of impact strength of composites. It can be noticed that Kevlar–epoxy (KE) composites give higher energy strength than UHMWPE–epoxy (PE) in 12 and 20 plies. The increasing percentage is about 18.5 and 5.7%. It can be observed in Figure 6 that samples are not destructed completely due to fiber continuity. Also, the delamination occurs obviously for UHMWPE–epoxy more than for Kevlar-based composite, which may due to weak binding between UHMWPE with an epoxy relative with Kevlar.

The force–time curves for Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites with 12 and 20 plies are illustrated respectively in Figure 7. The contact duration between indenter and composite surface is repented by the force–time curves, so the maximum force reaches with certain displacement. It can be seen that maximum force was (13,209, 18,734.9, 23,271.07 and 19,825.38 N) at the time (3.97, 4.43, 3.791 and 4.198 ms) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. The sharp peaks of KE composite are due to the lower ductility of Kevlar compared with UHMWPE. These results agree with the results of Ahmed et al. (2016). Kevlar-based composites (KE) showed lower impact force and crack propagates in the matrix with fast fiber breakage compared with PE composites, whereas the latter did not suffer from fabric breakage in 12 and 20 plies any more (see Figure 8). Figure 9 illustrates force–deformation curves, for 12 and 20 plies of Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites. Curve's slop is considered the specimen's stiffness and the maximum displacement. To investigate the impact behavior of the four different composites, the comparison was made among the relative force–deformation curves. The maximum displacement was 5.119, 3.443, 1.173 and 1.17 mm for 12KE, 12 PE, 20 KE and 20 PE, respectively. It seems that UHMWPE-based composite (PE) presents lower deformation than Kevlar-based composites (KE) at a same number of laminates, although the maximum displacement is for 12 PE and 12 KE (see Figure 8). Kevlar-based composites (KE) showed more damage than UHMWPE-based composite (PE), so the maximum displacement is always higher for KE specimens with maximum indenter trace diameter (D∼11.27 mm). The onset of cracks begins along fibers on the impacted side for 20 KE and 20 PE specimens with lower indenter trace (D∼5.42 and 5.96 mm), respectively (see Table 2). These results refer to the lower stiffness of KE composites (see the slope of the curve) relative to PE composites. This result agreed with (Vieille et al., 2013) when they found that the theoretical stiffness of laminated composite during drop-weight impact depends significantly on fiber nature (Fadhil, 2013). The matrix cracking is the first type of damage that may not change stiffness of composites overall. Material stiffness changes due to the stress concentration represented by matrix cracks, delamination and fiber breakage (Hancox, 2000). Briefly, the histogram (see Figure 10) showed that the best impact behavior was for 20 KE, highest impact force with lower deformation, indenter trace diameter and contact time. Absorbed energy–time and absorbed energy–deformation curves for composites are shown in Figures 11 and 12, respectively. The maximum absorbed energy was (36.313, 29.952, 9.783 and 6.928 J) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. Test period time is only 8 ms, but the time in which composites reached maximum absorbed energy was (4.413, 3.636, 2.394 and 2.408 ms). The maximum absorbed energy was for 12 KE with lower rebound energy because part of kinetic energy transferred to potential energy kept in the composite as material damage (see Figures 3 and 4). This composite absorbs more energy as material damage which kept as potential energy. Whereas other composites 12 PE, 20 PE and 20 KE showed less damage, lower absorbed energy and higher rebound energy, which appeared in different peak behavior as the negative value of energy. Also from the absorbed energy–time curves, it had been noticed significantly the maximum contact time of indenter with composite was 4.413 ms for 12 KE, which exhibits higher deformation (5.119 mm), whereas other composites 12 PE, 20 KE and 20 PE showed less damage, contact time and deformation as (3.443, 1.173, 1.17 mm), respectively.

The main goal of the current study is to evaluate the performances of armor composite made off of Kevlar and UHMWPE fabrics reinforced epoxy thermosetting resin under the low-velocity impact. Several plates of composites were prepared by hand layup. Izod and drop-weight impact tests were facilitated to get an indication about the absorbed energy and strength of the armors.