Search results

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.

In this paper the aim is that Aramid/alginate blended nonwoven fabrics were prepared, and the flame retardancy of the blended nonwoven fabrics was studied by thermogravimetric analysis, vertical flame test, limiting oxygen index (LOI) and cone calorimeter test.

The advantages of different fibers can be combined by blending, and the defects may be remedied. The study investigates whether incorporating alginate fibers into aramid fibers can enhance the flame retardancy and reduce the smoke production of prepared aramid/alginate blended nonwoven fabrics.

Thermogravimetric analysis indicated that alginate fibers could effectively inhibit the combustion performance of aramid fibers at a higher temperature zone, leaving more residual chars for heat isolation. And vertical flame test, LOI and cone calorimeter test testified that the incorporation of alginate fibers improved the flame retardancy and fire behaviors. When the ratio of alginate fibers for aramid/alginate blended nonwoven fabrics reached 80%, the incorporation of alginate fibers could notably decreased peak-heat release rate (54%), total heat release (THR) (29%), peak-smoke production rate (93%) and total smoke production (86%). What is more, the lower smoke production rate and lower THR of the blends vastly reduced the risk of secondary injury in fires.

This study proposes to inhibit the flue gas release of aramid fiber and enhance the flame retardant by mixing with alginate fiber, and proposes that alginate fiber can be used as a biological smoke inhibitor, as well as a flame retardant for aramid fiber.

The purpose of this paper is to develop a coated glass fiber fabric which can be used as the outer shell of firefighters' protective clothing and replace aramid fabric.

The silicone resin with excellent heat resistance was selected as the base solution. Silica nanoparticles, mica powder and ferric oxide were added into the coating solution, which was coated on the glass fiber fabrics. The vertical burning, thermal protective performance (TPP) value, second-degree burn time and water repellency of the coated fabrics were characterized.

Results showed that the dosages of the thickening filler were in the range 4%–6%; the coating solution has good viscosity. The optimal composition of fillers added in the silicone resin is silica nanoparticles 6%, ferric oxide 5% and mica powder 6%. The TPP value of the optimum coated fabric is 413 kW·s/m². The second-degree burn time is 4.98 s, which is obviously higher than that of the original glass fiber fabric (3.49 s) and that of the aramid fabric (3.82 s). The coated fabric has better thermal stability than aramid fabric.

The production cost of this coated glass fiber fabric was much lower than that of the aramid fabric.

Para-aramid fabrics see service in a great variety of applications, such as heavy weight lifting applications, penetration protective multilayer panels, etc. It is, therefore, increasingly important to understand the strain rate range at which the fabric has optimum mechanical properties. Although this is a field that has not been studied before, it is of great significance since it allows for the determination of the fabric’s layer location within the multilayered structure which offers maximum overall performance. The paper aims to discuss this issue.

Rectangular strips of PARAX 300 S8 woven para-aramid fabric underwent uniaxial tensile tests at various extension rates. The angle between two fibers at the center of each specimen was measured after the fabrics were elongated at different tensile extensions. This recovery angle was determined by visual analysis of the test video recordings after specimen unloading. Based on this, the recovery of the weaving form after unloading was also estimated for each tensile extension. A recovery degree based deformation characterization of the sections of a typical load/extension curve has been introduced.

The fabric does not appear to be strain rate sensitive for a strain rate range of 0.03 s-1 to 0.53 s-1, and its load/extension characteristics are generally not affected by the extension rate. However, break load and maximum elongation values appear reduced at actuator velocity of 2,400 mm/min and enhanced at 3,600 mm/min. Finally, the effect of extension rate on the different deformation zones of the material is reported and discussed.

The current research work offers a novel approach for the investigation of non-standard response of woven para-aramid fabrics when subjected to tensile loading under various strain rates. Additionally, a new approach is introduced to explain in detail the deformation zones based on the recovery degree of the fiber orientation angle after unloading.

The purpose of this paper is to present the influence of modifying the fabric surface made from basalt fibers by the magnetron sputtering of chromium and aluminum layers on its resistance to contact heat and comfort properties.

In order to modify the surface of basalt fabric, the process of physical deposition from the gas phase was used. It relies on creating a coating on a selected substrate by applying physical atoms, molecules or ions of specific chemical compounds. The trial of modification was carried out using the magnetron sputtering method due to the material versatility, application flexibility and ability to apply layers on substrates of various sizes and properties.

The findings obtained regarding the heat resistance to contact heat and thermal insulation (comfort) properties show different values depending on the type of metal deposited and the thickness of coating layer. It was found that the modification of basalt fabric surface at the micrometer level changes the tested parameters.

This paper presents the results of resistance to contact heat and thermal insulation properties only for the twill fabric made of basalt fiber. The surface modification of fabric was carried out using the chromium and aluminum of two values of layer thickness (1 and 5 µm).

So far, no tests have been carried out to modify the surface of fabric made from basalt fiber yarns using the magnetron sputtering method. In addition, it has not been studied, how the modification of fabric affects its resistance to contact heat and thermophysiological properties.

The new military specification for PCB base material was published on February 11th, 1987. This ‘G’ version is not merely an amendment of the ‘F’ version, but basically a new specification with far reaching consequences for both the base material manufacturers and the printed circuit board manufacturers. In this paper the major changes and also the latest introductions are discussed.

This research seeks to investigate the potential of using para‐aramid fibre fabric and yarn as an external reinforcement to existing structures. The purpose of this paper is to improve existing structural performance or to return the original design performance, during refurbishment. The research aims to investigate the potential for enhanced flexural strength and toughness in concrete beams, which may be required for change of use of buildings, where loadings may be subject to change. Buildings in earthquake zones may also benefit from additional toughness provided with external fabric/yarn reinforcement as a means of providing additional time for escape, for the occupants.

The test compared four types of concrete beams with different reinforcement material compositions and each set consisted of three beams. The beams were: plain reinforced concrete without any external form of reinforcement (RC), plain unreinforced beams with a para aramid sheet (KF), plain unreinforced beams with para aramid strips of yarn attached longitudinally (KY) and plain reinforced concrete beams with sheet fabric (RCKF). All of the para‐aramid material (fabric and yarn) was externally bonded to the samples, using a two part epoxy resin adhesive applied to a prepared surface. To determine the flexural strength and toughness a three point loading test was used to provide load and deflection data on the 12 (500 mm×100 mm×100 mm) concrete beams.

An increase in flexural strength and toughness was observed when para‐aramid was used in conjunction with steel reinforcement bar (re‐bar). The para‐aramid fabric and yarn produced similar results to the plain reinforced concrete beam in terms of flexural strength but not toughness.

An advantage of using para‐aramid as an external reinforcement, would be to utilise the large deflection the beam sustains under loading, whilst the fabric/yarn holds the beam together across the rupture plane. Although the testing did not prove that para‐aramid would be a viable alternative to steel re‐bar it did show that the material has the potential as an additional reinforcement that may be particularly useful where concrete structures are subject to large deformations or in need of repair.

The purpose of this paper is to present and analyze the effect of applied load and sliding velocity on the tribological behaviors of aramid fiber (AF) reinforced PA1010 which can be a potential material for transmission components.

The PA1010 composites with different content of AF are prepared and the tribology experiments are conducted on a block‐on‐ring wear tester under different experiment conditions. The wear mechanism of the composite is examined by means of scanning electron microscopy.

The addition of AF decreased the friction coefficient of PA1010 and increased its wear resistance. For optimal tribological properties 5∼15 wt% AF is preferred, while the wear resistance is best at 15 wt%. The friction coefficient decreased with increasing load and sliding velocity, but it is more sensitive to load. The main wear mechanism is abrasive wear at relatively low load and sliding velocity. With the increasing of load, the adhesive wear occurs in the matrix, meanwhile obvious fibrillation and layer peeling are observed on the fiber. When the sliding velocity increases, thermal adhesion and fiber debonding is the dominant mechanism.

PA1010 is a useful material for the alternative material of transmission components in industry.

PA1010 composite is prepared with a new kind of AF fiber and the tribology experiments have been carried out emphasizing on the variation of experiment conditions. The results could be useful for the material engineers.

A new aramid base material for use in laminates to be applied to advanced surface mount technology was developed. A new fibre based on PPDETA (Poly‐p‐phenylene/3,4'‐diphenylether terephthalamide) was found to have negative thermal and hygroscopic expansion coefficients, low ionic impurities and high affinity to epoxy and polyimide resins. The fibre was processed into fabrics and papers to be used as a base material for printed circuit boards for advanced surface mount technology. Impregnation with a new epoxy resin with high purity and high temperature resistance implemented the development of a new laminate with minimal electromigration and high dimensional stability. Thus, a new laminate was developed to be used for LCCC, PGA, COB, TAB, Flip‐Chips and other advanced surface mount technologies. Reliability of the laminate to electromigration between surface conductors, between plated‐through barrels, and between opposed conductors was found to be one of the highest available today. These types of behaviour were related to the high purity and high temperature resistance of both the reinforcement material and the resin. The short life of through‐hole plating in thermal shock was improved by the application of a new plating technology. Application to multilayer boards and laminates with a low dielectric constant is also being investigated.

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.