Structure Of Aramid Fibers Research Articles

Anti-Chemical Properties of Modular Protective Material

Previously, we developed the principle of constructing modular materials with specified properties, according to which organometallic composites, with nanoscale enzyme complexes introduced into them, are applied to a unified fabric platform. The resulting composites become a new platform for heterogeneous biocatalysis. Such a platform has high stability and good catalytic selectivity. The aim of the work is to study the properties of a unified fabric platform and to establish the possibility of giving materials (tissues) anti-chemical protective properties. The paper analyzes scientific and practical information on the production of composite fibrous materials with frame fibrous layers. The properties of a unified tissue platform and the mechanisms of protective action due to the enzymecontaining formulation applied to it are investigated. As a unified fabric platform on which other special modules are applied, it is proposed to use para-aramid protective fabric (Rusar fiber), as well as other types of fabrics – mixed aramid-viscose, aramid-cotton, aramid-polyacrylate, metaaramide (Nomex fiber). The physical properties and chemical structure of aromatic polyamides, possible directions for the production of aramid fibers, the structure and structure of aramid fibers, the mechanisms of chemical processes in polyinide compositions of various compositions are considered. Approaches to giving materials (tissues) anti-chemical protective properties are determined. The catalytic characteristics of fibrous materials functionalized by enzyme-polyelectrolyte complexes carrying out hydrolysis of organophosphorus compounds and mycotoxins have been studied.

U.S. Biowarfare Labs in Post-Soviet States

Previously, we developed the principle of constructing modular materials with specified properties, according to which organometallic composites, with nanoscale enzyme complexes introduced into them, are applied to a unified fabric platform. The resulting composites become a new platform for heterogeneous biocatalysis. Such a platform has high stability and good catalytic selectivity. The aim of the work is to study the properties of a unified fabric platform and to establish the possibility of giving materials (tissues) anti-chemical protective properties. The paper analyzes scientific and practical information on the production of composite fibrous materials with frame fibrous layers. The properties of a unified tissue platform and the mechanisms of protective action due to the enzyme containing formulation applied to it are investigated. As a unified fabric platform on which other special modules are applied, it is proposed to use para-aramid protective fabric (Rusar fiber), as well as other types of fabrics – mixed aramid-viscose, aramid-cotton, aramid-polyacrylate, metaaramide (Nomex fiber). The physical properties and chemical structure of aromatic polyamides, possible directions for the production of aramid fibers, the structure and structure of aramid fibers, the mechanisms of chemical processes in polyinide compositions of various compositions are considered. Approaches to giving materials (tissues) anti-chemical protective properties are determined. The catalytic characteristics of fibrous materials functionalized by enzyme-polyelectrolyte complexes carrying out hydrolysis of organophosphorus compounds and mycotoxins have been studied

Estimation of aramid fiber/epoxy interfacial properties by fiber bundle tests and multiscale modeling considering the fiber skin/core structure

In this work, the aramid fiber/epoxy interfacial normal bonding property and interfacial shear property were estimated by transverse fiber bundle tensile (TFBT) test and 45° fiber bundle tensile (45FBT) test, respectively. The fracture surfaces of the fiber bundle samples after the mechanical test were observed to investigate the micro failure mechanisms. The interfacial debonding was found coupled with fibrillation of the fiber surface due to the apparent skin/core structure of aramid fibers. Furthermore, the multiscale model based on the generalized methods of cells (GMC) considering the skin/core structure and the fiber/matrix interphase was established to calculate the micro stresses. The interfacial normal strength (IFNS) in the TFBT specimen and interfacial shear strength (IFSS) in the 45FBT specimen were determined by the combination of the experimental and analytical results. Eventually, the effects of skin/core stiffness and thickness on the calculated IFNS and IFSS values were investigated.

Effect of Treating Time on Mechanical Properties and Structure of Aramid Fibers during Heat Drawing

High modulus Poly (p-phenyleneterephalamide)(PPTA) fibers was prepared by heat drawing process, in which the fibers rearranged their structures for further improvements in their crystalline perfection, crystal line orientation. The modulus of PPTA fibers could be improved when fibers treated in an appropriate condition. The influences of heat treating time on the structures of the fibers and their properties were investigated by using two-dimensional wide-angle scattering (WAXS).

Effect of Tension on Mechanical Properties and Structure of Aramid Fibers during Heat Treatment

The heat treatment was carried out to modify the aramid fibers, and the effect of tension on the mechanical properties and structure was investigated through Fiber Strength Equipment, viscosity, XRD and SEM . The results show that fibers，strength slightly decrease, but modulus increase significantly according to the increasing of tension at 480°C and 10s, and reach a maximum when the tension value is 300 g. After heat treatment, molecular weight decrease and the degree of crystallinity increase. SEM show that there is little effect on the surface topography of the fibers during treatment.

Crystal Structure Analysis on Aramid Fiber/Fibrids and Paper by Polarized Light Microscopy

The crystal structure of aramid fibers is highly orientated. The structure of aramid fibers with various manufacturing processes and aramid paper sheets were analyzed and observed by using polarized light microscope (PLM). The change and its law of aramid fiber crystal structure in such processes as aramid fiber mamufaturing of aramid fiber/fibrids, forming of aramid paper sheets, and heat treatment were analysed. The relationship between the structural feature of aramid fibers and the performance of aramid paper was also discussed.

Effect of Surface Treatment on the Properties of Kevlar Fibers by a Novel Chemical Method

The surface of kevlar fiber was modified by phosphoric acid solutions (H3PO4) in this article. The structure and morphology of the modified fiber were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The results showed that some polar groups were introduced into the molecular structure of aramid fibers. The interfacial properties of aramid fiber/epoxy composites were investigated by the single fiber pull-out test (SFP). The results showed that the interfacial shear strength (IFSS) of aramid/epoxy composites was remarkbly improved after surface modification and the breaking strength has not been affected appreciably. It provided an efficient method to make the surface modified Kevlar fiber for the application for the advanced composites at a lower production cost.

Surface Treatment of PPTA Fiber and Properties of its Composite Materials

Surface modification of Poly(ρ-phenylene terephthalamide) (PPTA) fiber has been considered an effcient way to increase the interfical bonding of the fiber/epoxy composites. In this article, the hydrogen peroxide solutions (H2O2) was used to treat the PPTA fiber based on an orthogonal experimental design. The optimum conditions of H2O2 treatment were concentration of 40%, treating temperature 40°C and treating time 60min. The morphology of the modified fiber were characterized by scanning electron microscope (SEM). The interfacial properties of aramid fiber/epoxy composites were investigated by the single fiber pull-out test (SFP. The results showed that the interfacial shear strength (IFSS) of aramid/epoxy composites was remarkbly improved which was attributed to the fact that some polar groups were introduced into the molecular structure of aramid fibers and the physical structure of the treated fibers was not etched obviously.