Justification of Starching Cotton and Aramid Yarns by Industrial and Laboratory Processes.

The development and application of new types of fibres and their wider application influence the continuous invention of a more economical starching process, as one of the most expensive stages in the technological process of woven fabric production. For example, aramid fibres are increasingly used in clothing with effective protection from mechanical, thermal and abrasion exposure. Simultaneously, comfort and regulation of metabolic heat are extremely important, and this is achieved by using cotton woven fabrics. For such a woven fabrics to satisfy the protective properties and the possibility of all-day wear, fibre is needed, and thus a yarn, that will enable the efficient production of fine, light and comfortable protective woven fabrics. This paper investigates the influence of starching on the mechanical properties of aramid yarns and their comparison to cotton yarns of the same fineness. This will lead to knowledge about the efficiency and necessity of aramid yarn starching. The tests were carried out on an industrial and laboratory starching machine. According to the obtained results, the necessity and the improvement of the physical-mechanical properties of cotton and aramid yarns can be determined, both by industrial and laboratory starching. Finer yarn starched by the laboratory starching process achieves greater efficiency in the yarn's strength and resistance to wear, which indicates the need for starching aramid yarns, especially fineness 16.6 × 2 tex, but also finer ones.

Thermal Protective Properties and Breathability of Multilayer Protective Woven Fabrics for Wildland Firefighting.

A firefighter in the wildland fields spends an average of 8 to 16 h during which he encounters enormous physical effort and very demanding outdoor conditions of high temperatures. Research shows that the most common injuries are due to the occurrence of heat stress, and not due to lack of protection against burns. Therefore, for this very specific field of firefighting, it is necessary to provide clothing that will, in addition to adequate flame protection, provide good comfort properties such as lightweight suits, good porosity and breathability, so that gaseous sweat and heat generated by body heating can be released into the environment. The aim of this study was to determine the influence of structural parameters of multi-weft woven fabrics on two mutually contradictory properties-breathability and thermal protection. When designing fabrics, the goal was to produce a structure with a high proportion of volume pores, which, regardless of the increased volume of the fabric, insure the fabric mass would be acceptably small. Volume pores in the fabric have two roles-as a heat insulator and as an inhibitor of the breathability of the material. The analysis of the obtained results showed that the thickness and mass of the fabric have a greater influence on the water vapor resistance, while the heat transmission property is more affected by the thickness, porosity and fiber content.

Application of 3D-Woven Fabrics for Packaging Materials for Terminally Sterilized Medical Devices.

This research aimed to test a newly developed 3D fabric for use in a hospital sterilization unit as a packaging material. Two basic properties were tested: the efficiency of the microbial barrier, and the bursting strength of the woven fabric, determined with a steel ball. Material deformations caused by bursting are common in medical sterilization, as a consequence of the packaging of the medical tools needed in surgery. Six 3D-fabric samples were woven from the same warp, with three weft densities and in two different weaves. The weaving conditions and other construction characteristics of the fabrics were the same. To determine the effectiveness of the microbial barrier, bacterial endospores of an apathogenic species of the genus Bacillus, Geobacillus stearothermophilus and Bacillus atrophaeus, were used. Mechanical testing of the 3D-woven fabric, i.e., the bursting strength of the fabric using a steel ball, was carried out according to the standard method. The results showed the exceptional puncture strength of the woven fabrics and their formation of an effective microbial barrier, i.e., complete impermeability to microorganisms in five samples, which is the main condition for possible use as a packaging material in medical sterilization. Sample 3tp did not provide an effective microbial barrier and did not meet the basic requirements for use in medical sterilization.

Design of Experiment Approach to Optimize Hydrophobic Fabric Treatments.

Polymer materials can be functionalized with different surface treatments. By applying nanoparticles in coating, excellent antimicrobial properties are achieved. In addition, antimicrobial properties are enhanced by hydrophobic surface modification. Therefore, the goal of this work was to modify the process parameters to achieve excellent hydrophobicity of polymer surfaces. For this purpose, a Design of Experiment (DoE) statistical methodology was used to model and optimize the process through six processing parameters. In order to obtain the optimum and to study the interaction between parameters, response surface methodology coupled with a center composite design was applied. The ANNOVA test was significant for all variables. The results of the influence of process parameters showed that, by increasing the pressure, concentration of hydrophobic compounds and dye concentration, water vapor permeability was enhanced, while by decreasing weight, its efficiency was enhanced. Moreover, the increase in the temperature enhanced water vapor permeability but decreased the resistance to water wetting. An optimal process with ecologically favorable 6C fluorocarbon (68.802 g/L) surpassed all preliminary test results for 21.15%. The optimal process contained the following parameters: 154.3 °C, 1.05 bar, 56.07 g/L dye, 220 g/m2 fabric. Therefore, it is shown that DoE is an excellent tool for optimization of the parameters used in polymer surface functionalization.

Bicomponent Carbon Fibre within Woven Fabric for Protective Clothing.

For the purpose of this research, six types of woven fabrics with different proportions of bicomponent carbon fibres (CF), differently distributed in the fabric, were woven and tested. Fibre composition in the core and sheath was determined with X-ray spectroscopy (EDS). Two types of bicomponent CF were selected which are characterised by different proportions of carbon and other polymers in the fibre core and sheath and different cross-sections of the fibres formed during chemical spinning. Physical-mechanical properties were investigated, as well as deformations of fabrics after 10,000, 20,000 and 30,000 cycles under biaxial cyclic stress on a patented device. Tests of the surface and vertical electrostatic resistance from fabric front to back side and from the back side to the fabric front were conducted. According to the obtained results and statistical analyses, it was concluded that the proportion of CF affects the fabric's physical and mechanical properties, the electrostatic resistance as well as the deformations caused by biaxial cyclic stresses. A higher proportion of CF in the fabric and a higher proportion of carbon on the fibre surface, gave lower electrostatic resistance, i.e., better conductivity, especially when CFs are woven in the warp and weft direction. The higher presence of CF on the front of the fabric, as a consequence of the weave, resulted in a lower surface electrostatic resistance.

Influence of Fabric Weave on Thermal Radiation Resistance and Water Vapor Permeability.

In this work, aramid fibers were used to develop new, high-performance fabrics for high-temperature protective clothing. The research was based on the impact of the weave structure on fabric resistance to radiant heat. The goals of the research were primarily related to the development of new fabric structures created by the weave structure, which gives better protection of the body against high temperatures in relation to the standard weave structures that are used today. According to the results obtained it can be concluded that the fabric weave significantly affects the fabric structure, which consequently determines the effectiveness of protection against high temperatures. The justification for the use of multi-weft and strucks weave structure, which provides greater thermal protection and satisfactory breathability than commonly used weave structures, was ascertained.

Transcobalamin II deficiency at birth.

Transcobalamin II deficiency (# MIM 275350) is a rare, recessively inherited disorder of cobalamin transport that leads to intracellular cobalamin depletion with secondary impairment of methionine synthetase and methyl-malonyl CoA mutase activities. Affected individuals may suffer from long-term neurological sequelae if therapy with intramuscular hydroxocobalamin is not initiated promptly. We report two sisters with complete absence of transcobalamin due to homozygosity for a novel mutation (c.insC110) in the TCN2 gene that leads to a premature stop codon and non-functional protein. The older sister, now 4.5 years old, presented at 6 weeks of age with pancytopenia, protein losing enteropathy and a rapidly declining clinical course. Prompt therapy with 1mg hydroxocobalamin/day led to full recovery within days. Her now 1.5 year old sister was diagnosed shortly after birth and was started on hydroxocobalamin prior to onset of clinical symptoms. Interestingly, urinary methylmalonic acid excretion was increased significantly during the first days of life suggesting that functional cobalamin deficiency is present also during fetal life, although not giving rise to clinical symptoms until well after birth.