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In this study, a three-dimensional (3D) model of a yarn pullout test for plain woven fabrics is introduced. The main focus of the study is on the realization of a 3D fabric geometrical model, the incorporation of anisotropic material properties and the validation of yarn and fabric finite element meso-models using experimental results. The material properties of yarn and fabric were assumed to be linear orthotropic. The required engineering constants were obtained from experimentally-measured tensile, compression and shear diagrams. The accuracy of the applied engineering constants was investigated by finite element (FE) modeling of yarn pure bending. The yarn pullout test was modeled with the Abaqus FE package. The fabric sample was modeled with solid elements for the weft and warp yarns in the interlacing points, which are directly involved in the yarn pullout, plus shell elements for the parts of the fabric that undergo only shear deformation. The effects of the geometrical model and material anisotropy were investigated and the predicted force—displacement profiles of the yarn pullout test were compared with experimental measurements.

The purpose of this study is to consider the influence of laminating temperature on nanofiber/laminate properties. Hot-press laminating was carried out at five different temperatures and nanofiber web morphology was observed under an optical microscope. Also, air permeability experiments were performed to examine the effect of laminating temperature on breathability of multilayer fabric. Optical microscope images showed that the nanofiber web began to damage when laminating temperature was selected above the melting point of adhesive layer. Air permeability decreased with increasing laminating temperature. It is also observed that the adhesive force between layers was increased by increasing laminating temperature.

The electrospinning of the biopolymer chitosan (CS) and poly(vinyl alcohol) (PVA) was investigated with 90% acetic acid as the solvent and with different CS/ PVA ratios. The long chains of high-molecular-weight CS prevented it from forming nanofibers in a high-voltage field. The treatment of CS under high-temperature alkali conditions reduced its molecular weight exponentially with the treatment time and caused a reduction of the viscosity consequently. PVA, acting as a plasticizer and accompanied by the alkali-treated CS of lower viscosity, made the electrospinning of CS/PVA blends possible. The effects of the duration of the alkali treatment on the molecular weight of CS and its viscosity were investigated and optimized. The diameter of the bicomponent nanofiber decreased proportionally with the increase in the CS portion, whereas the surface porosity increased inversely. Fourier transform infrared studies illustrated that the alkali treatment or blending of CS with PVA had no effect on its chemical nature.

The use of fine fiber has become an important design tool for filter media. Nanofibers-based filter media have some advantages such as lower energy consumption, longer filter life, high filtration capacity, easier maintenance, low weight rather than other filter media. The nanofibers-based filter media made up of fibers of diameter ranging from 100 to 1,000 nm can be conveniently produce by electrospinning technique. Common filter media have been prepared with a layer of fine fiber on typically forming the upstream or intake side of the media structure. The fine fiber increases the efficiency of filtration by trapping small particles, which increases the overall particulate filtration efficiency of the structure. Improved fine fiber structures have been developed in this study in which a controlled amount of fine fiber is placed on both sides of the media to result in an improvement in filter efficiency and a substantial improvement in lifetime. In the first part of this study, the production of electrospun nanofibers is investigated. In the second part, a different case studyis presented to show how they can be laminated for application as filter media. Response surface methodology (RSM) was used to obtain a quantitative relationship between selected electrospinning parameters and average fiber diameter and its distribution.

Electrospun nanofiber web has many potential applications due to its large specific area, very small pore size and high porosity. However, the mechanical properties of nanofiber web are very poor for use in textile application. To remedy this defect, the laminating process could accomplish in order to protect nanofiber web versus mechanical stresses. In this paper, direct tracking method as an image analysis based technique for measuring electrospun nanofiber diameter has been presented. The usefulness of the method for electrospun nanofiber diameter measurement is discussed. Such automated measurement of nanofiber diameter can be used to obtain better laminated webs.