Nonwoven Webs Research Articles

Heat-setting Effect on the Morphology and Phase Structures of PPS Nonwovens

Thermal shrinkage has for long been a critical issue in nonwoven industrial applications. A dimensionally stable nonwoven web with excellent mechanical property was achieved by heat treatment with ...

Electrospun Fibre Webs Templated Synthesis of Mineral Scaffolds Based on Calcium Phosphates and Barium Titanate.

The current work focuses on the development of mineral scaffolds with complex composition and controlled morphology by using a polymeric template in the form of nonwoven fibre webs fabricated through electrospinning. By a cross-linking process, gelatine fibres stable in aqueous solutions were achieved, these being further subjected to a loading step with two types of mineral phases: calcium phosphates deposited by chemical reaction and barium titanate nanoparticles as decoration on the previously achieved structures. Thus, hybrid materials were obtained and subsequently processed in terms of freeze-drying and heat treating with the purpose of burning the template and consolidating the mineral part as potential bone implants with improved biological response by external stimulation. The results confirmed the tunable morphology, as well as the considerable applicability of both as-prepared and final samples for the development of medical devices, which encourages the continuation of research in the direction of assessing the synergistic contribution of barium titanate domains polarisation/magnetisation by external applied fields.

Formation of Nonwoven Webs with Electrostatic Field Effect

The non-woven materials industry is one of the fastest-growing industries in the world with the ability to produce materials in less time, specifications, and better prices. nonwoven materials are defined as a web of guided or random fibers that are bonded by friction, interlacement or adhesion. In this research, the rotary electrospinning system was used and a prototype was made to study the process and the complete visualization in terms of the correlation of the electrostatic forces to the formation of nanofibers by preparing polymeric solutions and exposing them to the electric field between the positive electrode (the serrated cylinder) and the Grounded electrode (plate) and produced high-precision fibers with a diameter (185nm) at 25 kV, whereas the installation of polyvinyl alcohol (PVA) was with different concentrations and the formed fibers possessed an effective surface and deposited on a collector electrode forming nonwoven webs and high productivity is the most important feature of this system compared with the traditional electrospinning system.

One-pot synthesis of cellulose-based nonwoven web incorporated with chitosan for hemostat applications

Water-soluble chitosan and wood pulp fiber–based nonwovens were produced using wet-laying technology, and their properties were investigated for the potential application for severe hemorrhage. The pores of the wood pulp nonwovens were completely covered as the concentration of chitosan was increased. A phosphate buffer solution uptake of 997% was attained in the nonwoven loaded with chitosan concentration of 1.5 w/v%. The deposition of blood cells was found to increase with an increase in the water-soluble chitosan concentration. The blood-clotting time was found to be 170 s, making the developed nonwoven to promote blood-clotting mechanism by creating mechanical barrier to reduce the blood loss.

Comparison of acid and water-soluble chitosan doped fibrous cellulose hemostat wet laid nonwoven web for hemorrhage application

Fibrous hemostat was produced using wet laying technique comprising of acid and water soluble chitosan with fibrous cellulose. The hemostatic efficiency and their structural properties were evaluated using blood clotting time, whole blood adhesion and analytical characterization techniques. The maximum concentration of chitosan utilised for the production of nonwoven was 1.5 w/v % upon which increased the viscosity of the solution. The absorption of phosphate buffer solution was found to be 1117% for acid soluble chitosan based nonwoven whereas for water soluble chitosan based nonwoven was 997%. Increased red blood cells and platelets were found to be higher in acid soluble chitosan compared to water soluble chitosan based cellulose nonwoven. The blood clotting time for acid soluble chitosan nonwoven was found to be 166 s and water soluble chitosan nonwoven was 170 s. The developed hemostat have potential application in reducing blood loss and also inducing the blood coagulation pathway which was confirmed by the adhesion of platelets on to the surface of nonwoven web.

Film Fiber Radio-Absorbing Material

The dielectric properties of nonwoven webs and polymer films filled with dispersed carbon web, as well as multilayer materials obtained by addition of webs and films, were investigated. Webs and films have a pronounced interference mechanism of absorption of electromagnetic waves. Dielectric properties with an asymmetric structure relative to the middle of the thickness of the multilayer materials depend on the side on which electromagnetic radiation enters the material. Multilayer materials based on nonwoven web and polymer films have an interference absorption mechanism, but their use expands the frequency range of absorption of electromagnetic radiation.

Meltblown Polylactic Acid Nanowebs as a Tissue Engineering Scaffold.

Polylactic acid (PLA) nanofiber nonwovens have recently come under more vigorous investigation for their use as tissue engineering scaffolds owing to its ability to mimic the physical properties of naturally occurring human extracellular matrix in a variety of host tissues. Currently, the majority of available research on PLA nanowebs has focused on their creation through electrospinning. The goal of this study was to evaluate meltblown nonwoven webs made of nanodiameter PLA fibers for their application as a tissue engineering scaffold. Meltblown PLA fabrics were produced with a variety of different crystallinities, tensile moduli, and pore diameters. One fabric with mechanical properties similar to human dermis was selected as a scaffold to study attachment, proliferation, and migration of human dermal fibroblasts over 1, 3, 7, and 14 days without the use of additional cell adhesion molecules. The 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide assay showed good proliferation from day 1 to 3 (P = 0.026) and up to 7 days of culture (P = 0.005) but without increase from day 7 to 14. Electron microscopy demonstrated adequate cellular attachment and surface migration at 1, 3, 7, and 14 days. Finally, confocal microscopy was used to investigate cellular penetration into the scaffolds. The investigation found that cells were able to penetrate fully through the thickness of the scaffold. The successes of this initial experiment are promising and confirm that meltblown nanofiber nonwovens are a viable avenue for tissue engineering scaffolds. Hopefully, these conclusions will open the door for others to pursue research in this exciting field.

Mechanical properties evaluation of nonwoven industrial cotton waste produced by needle punching method

This paper describes the fabrication method and mechanical characterization of nonwoven fabrics from industrial fabric wastes by different machine variables. Cotton waste fibres underwent the mechanical recycling methods, needle punching process and worked into a continuous web of nonwoven fabrics. The measurement method of full factorial design of experiment was implemented in this study as a systematic and efficient way to distinguish between the interaction of more than one factor which are the fibre feeder speed and the number of stacking layers, respectively. Three different fibre feeder speed of 1.8 m/s, 2.2 m/s and 2.8 m/s and three levels of stacking layer (4, 5 and 6 layers) were examined. Analysis of variance (ANOVA) was used to determine the significant factors that influenced the mechanical properties of the web nonwoven fabrics. The mechanical properties of nonwoven web were measured by bursting strength test and puncture resistance test. The results displayed that the difference in fibre feeder speed and number of stacking layer significantly affect the puncture resistance performance. S26L web resisted the highest load during puncture resistance test which is 70.5 N while S14L resisted the lowest load of 25.5 N. Whereas, bursting strength performance was only affected by the fibre feeder speed. Lower fibre feeder speed produced stronger nonwoven fabric. Hence, the faster the fibre feeder speed and the higher number of stacking layer give good puncture resistance properties of nonwoven fabrics while the bursting properties of nonwoven fabrics shows the opposites results.

Preparation of non-woven nanofiber webs for detoxification of nerve gases

Non-woven nanofiber web with high surface areas and abundant functional groups were fabricated through electrospinning and chemical vapor deposition (CVD) in order to develop functional non-woven nanofiber webs for detoxifying simulant of chemical warfare agents. Functional groups that can hydrolysis diisopropyl fluorophosphate (simulant of G-series agents) were selectively modified onto the electrospun PAN nanofibers without causing deterioration of the fiber morphology. In order to achieve the most suitable conditions for functionalization, the CVD reaction temperature was adjusted and various functional groups were introduced. Here, CVD of ethylene diamine at 120 °C of reaction temperature shows the best detoxifying efficiency against diisopropyl fluorophosphates (DFP), which is simulant of G-series chemical warfare agent (complete removal of DFP within 24 h under humid condition). Density functional theory (DFT) calculations clarified the optimized functional groups for effectively detoxifying nerve gas agent (G types). Both of simulation and experimental results prove that the co-existence of hydroxyl and amine groups will be beneficial in detoxifying reaction (over 80% decomposition within 4 h).

Direct Z-scheme heterostructure of p-CuAl2O4/n-Bi2WO6 composite nanofibers for efficient overall water splitting and photodegradation

Constructing heterostructures can facilitate photoinduced charge separation, leading to enhanced photocatalytic performance. However, spatial separation of charge carriers in traditional type II heterojunctions is at the expense of their redox ability. In this paper, well-designed direct Z-scheme systems (ZSS) of p-CuAl2O4/n-Bi2WO6 composite nanofibers with uniform non-woven web nanostructure was built by electrospinning technique and solvothermal reactions. The formation mechanism of the ZSS and the charge migration pathway is investigated in detail. Results show that as-prepared composite nanofibers exhibit desirable photocatalytic performance for overall water splitting due to its stronger redox power and efficient charge separation. Meantime, it shows great activity for photodegradation of various organic pollutant models (RhB, MO, 4-NP), which is 1 order of magnitude higher than the single-component CuAl2O4 and Bi2WO6. Furthermore, the composite nanofibers exhibit well separable properties by natural sedimentation because of its ultra-long and non-woven web nanostructure. The paper explores CuAl2O4 and its Z-scheme heterostructures in water splitting for the first time, which may highlight its new applications.

Air Permeability of Multilayer Needle Punched Nonwoven Fabrics

Air permeability of multilayer nonwoven fabrics obtained by combining needle punched webs made from fibers with different linear mass densities is investigated. The optimal composition of nonwoven webs providing multilayer fabrics with increased permeability is determined. A model linking the air permeability of multilayer fabrics with their thickness, which depends on the number of layered webs, is proposed. The air filtration mechanism in webs and multilayer fabrics is substantiated. The process of structural formation of the webs and multilayer fabrics is considered. The influence of the structure of the webs and multilayer fabrics on their air permeability is determined.

Preparation and properties of eccentric hollow fiber nonwovens for acquisition distribution layer

Through-air bonding is one of the thermal methods of bonding fibers in the production of nonwoven webs, and they are widely used in disposable sanitary products, especially in the acquisition distribution layer of diapers. In this article, the through-air bonded nonwoven fabrics were successfully prepared by ethylene–propylene fibers (polyethylene and polyethylene terephthalate (PE/PET)) and eccentric hollow fibers (PE/PET). The influence of process parameters such as the ratio of fibers was discussed for performance of through-air bonded nonwoven. Besides, the surface morphology, physical characteristics (thickness and breaking strength), air permeability, moisture permeation, liquid permeability, and absorption properties test of the nonwoven fabrics were investigated. The results demonstrated that the addition of eccentric hollow fiber increased the permeability, mechanical property, and the core absorption effect of the through-air bonded nonwovens. According to the results, the fabrics made of eccentric hollow fibers have good absorption and liquid transfer characteristics; the permeation time and wetback were found to be 0.85 s and 0.03 g, respectively.

Dynamics of the Remote and Contact Interaction of Liquid Droplets with Film-Like and Fibrous-Porous Polymeric Materials

The problem of inkjet printing quality was considered for the case of synthetic polymer-based film-like and fibrous-porous materials. Physical modeling of inkjet printing on polypropylene using water-based ink revealed remote interaction of liquid droplets with films and nonwoven webs, responsible for the droplet path deviation from the vertical fall and the droplet moving across the polymer film surface after the contact or holding at the fiber ends. Relationships were established and controlling techniques were proposed for the processes of absorption and spreading of liquid droplets in the materials to be printed with the view of increasing the accuracy of printing information symbols and reducing ink consumption.

Hypocoercivity for geometric Langevin equations motivated by fibre lay‐down models arising in industrial application

In this article we review a powerful and fairly simple hypocoercivity method and its application to qualitative analysis of industrially relevant fibre lay‐down models. The hypocoercivity strategy is formulated in an abstract Hilbert space setting with all necessary conditions; we provide some interpretation of these conditions and briefly explain why they are needed to make the machinery working. Once the conditions are fulfilled we gain exponential decay of the strongly continuous semigroup associated to the fibre lay‐down process at an explicitly known rate. We interpret this result as describing for instance homogeneity of nonwoven fibre webs. Primarily, this article portrays the concepts, however it is based on original results by Grothaus and Stilgenbauer, which can be found in the previous studies.

Influence of sea polymer removal on sound absorption behavior of islands-in-the-sea spunbonded nonwovens

This work presents the results of efforts focused on the development of relatively lightweight and fibrous acoustic webs. For this objective, nonwoven webs that contain bicomponent filaments with islands-in-the-sea cross sections were produced by spunbonding, which involves the extrusion of sea and island polymer melts through dies, cooling and attenuating the bicomponent filaments by high-velocity air streams. Nylon 6 and polyethylene were used as the island and sea polymers, respectively. Webs were hydroentangled with high-pressure water jets prior to the dissolving process to obtain fiber entanglement. Sea polymer was removed from the spunbonded nonwovens by using a reflux dissolution setup. Weight, thickness, air permeability, pore size and sound absorption coefficients of the nonwoven samples were measured before and after the sea polymer removal. Results demonstrated that sea polymer removal led to further bicomponent filament fibrillation, which affected sound absorption positively. The structure with the higher number of island fibers had better acoustical properties. Lightweight and fibrous acoustic nonwovens can be obtained with the method given in this study.

Heat insulation characteristics of multi-layer nonwovens

PurposeThis paper aims to deal with the thermal resistance of multilayer nonwovens. The effect of fibre denier, cross-sectional shape and positioning within the layers were analysed with respect to the thermal resistance. Moreover, effect of compression on thermal resistance of the multilayer nonwoven structure have also be studied.Design/methodology/approachThe study involves multiple layering of thermal bonded nonwoven webs and the effect of fibre denier and positioning of different nonwovens from the hot plate. To avoid the increase in thermal resistance because of the air gaps between layers, the nonwovens were enclosed within an acrylic frame to compress them to a thickness of 12 mm. Compressional behaviour of the nonwovens were tested at a rate of 5 mm/min with peak compressive load of 50 N. Multilayer nonwoven assemblies were tested for thermal resistance with compressive pressure of 3.5 gf/cm2 and compared with that tested at zero pressure.FindingsIn the study, three-layered nonwoven structure, provided better thermal resistance than their single component counterparts. The structural characteristic of the multilayer nonwovens affected the conductive, convective and the radiative heat transfer. In a multi-layer nonwoven, the top most layer should have the finest fibre as possible. Second preference may be given to the middle and followed by bottom layers in terms of fibre fineness. However, fine solid fibres performed poorly in terms of compression and recovery resulting in poor thermal resistance under compressive load.Originality/valueThe experimental approach of controlling thickness while evaluating the thermal resistance will help in nullify the effect of air gaps between the layer interface, thus focussing on the effect of fibre denier and the positioning of nonwovens. This paper also discusses the unique properties of fine solid fibre and hollow fibres and their role in providing better thermal insulation for extreme cold weather applications.

Investigation of sound absorption properties of nonwoven webs produced from chicken feather fibers

As a consequence of modern life and technology, noise causes many negative side effects, especially with regard to health. Today, the presence of acoustic problems in transport vehicles such as airplanes, cars and train wagons has become one of the major problems of modern life. Many methods and materials have been developed to provide acoustic comfort in indoor spaces. One of them is the development and application of sound-absorbing materials. Nonwoven webs, which are considered to be the most ideal materials for sound insulation, have micron-sized pores as well as large surface areas. Among these materials, materials with double-layered porosity have greater effect. In recent years, researchers are increasingly turning to the development of sound-absorbing materials from production waste and natural materials that are easily decomposed in the environment. In this study, the sound-absorbing properties of nonwoven webs produced from chicken feather fibers, a by-product in chicken production and a significant amount of waste, were investigated. For this purpose, nonwoven web samples with different parameters were produced by using different binding materials by using thermal bonding method. The sound absorption coefficient and sound transmission loss values of the samples were measured and evaluated. As a result of the analyses, the influence parameters such as thickness, bulk density and porosity on the sound insulation properties of the produced samples was revealed. The assumptions concerning the mechanism of sound insulation of nonwoven webs produced from chicken feather fibers are detailed. Studies have shown that nonwoven webs from chicken feather fibers can be used as soundproof materials because of their good sound-absorbing properties.

The Properties of Mesh Reinforced Nonwoven Composites

To create the heat-bonded geotextile with desirable properties, the mix of fibres (hemp, recycled polyethylene terephthalate and polypropylene fibres) for nonwoven webs formation and additional polypropylene reinforcing mesh are used. The results of the study on the influence of the reinforcing mesh on the properties of nonwoven composites (NWCs) are presented. Mechanical properties, water penetration and air permeability of the thermoplastic mesh reinforced NWCs depend on the hemp fibre pre-treatment time, mass per unit area and thickness of the used web and location of the reinforcing mesh. Obtained results allow concluding that mechanical as well as water penetration characteristics of the produced heat-bonded geotextiles are higher, while air permeability is comparable to the properties of the commercial prototype.

Effect of sea component dissolution on fibrous structure of islands-in-the-sea spunbond nonwovens

This work presents the preliminary results of our efforts that focused on the development of lightweight and more fibrous nonwoven. For this objective, nonwoven webs that contain bicomponent filaments with island-in-the-sea cross section was produced by spunbonding, which involves extruding of sea and island polymer melts through dies, cooling, and attenuating the bicomponent filaments by high velocity air streams. Nylon-6 and Polyethylene were chosen as the island and sea polymers, respectively. Bonding process was applied to web first to keep structural integrity after removing the sea polymer. The web was hydroentangled with high speed water jets prior to the dissolving process to obtain fiber entanglement. Xylene, which is one of the few chemical that can dissolve Polyethylene, was used for the dissolution of the sea component from the fibrous structure of the spunbond nonwoven. Removal of the sea polymer from spunbond nonwovens that contain bicomponent filaments with islands-in-the-sea cross section was achieved by the developed dissolution process. Weight, thickness, and area of the nonwoven samples changed after the dissolution. After removing the sea polymer, spunbond nonwoven contains only thin island fibers and also gets lighter. Lightweight and more fibrous nonwovens can be obtained with the method given in this study.

Measuring fiber orientations in nonwoven web images using corner detection by Bézier fitting curves

This paper describes a novel method for measuring fiber orientations in nonwoven web images by using Bézier fitting curves to detect corners of fiber edges and to separate crossing fiber edges. First, the Canny detector was adopted to extract fiber edges. Second, Bézier curve fitting was used to fit each fiber edge for calculating the curvature of every point on the edge. Third, corner points were detected by locating points where the curvatures were minimal on various edges and below the threshold to divide edges into segments for orientation calculations. Last, a formula calculating the fiber orientation statistics based on the Euclidean distance was established. The experiment results demonstrated that the proposed method is robust for analyzing different nonwoven web images, and has a high accuracy for corner detection and fiber orientation calculation.