Nonwoven Glass Fiber Research Articles

Scalable, roll-to-roll manufacturing of multiscale nanoparticle/fiber composites using electrophoretic deposition: Novel multifunctional in situ sensing applications

Multiscale composites, where traditional fiber reinforcements are combined with nanoscale reinforcements, have emerged as multifunctional materials and have found potential for in situ strain and damage sensing, and energy harvesting/storage applications. Critical to the advancement of future applications is the development of manufacturing techniques that are industrially scalable. Electrophoretic deposition (EPD) can uniformly coat functionalized nanoparticles, such as carbon nanotubes (CNT), on conductive and non-conductive fiber substrates, producing multiscale composites with controlled microstructures and functional properties. In this research, a pilot-scale roll-to-roll EPD system is developed to continuously manufacture CNT-integrated fabrics for in situ sensing applications. Based on fundamental knowledge of CNT deposition mechanisms, key experiments are conducted to determine electrode configurations to optimize deposition yield in the roll-to-roll process. Functionalized CNTs are then deposited on 4–6 m long continuous rolls of randomly oriented non-woven glass fiber veil with different areal weights, and the CNTs form a continuous, conductive fiber-level coating. The thin and open fabric microstructure allows embedded sensors that are minimally invasive to the composite structure and allow ultraviolet (UV) light transmittance for use with UV-curable resins. The electrically conductive CNT network created on the fabric allows for the integration of sensing functionality. Short beam specimens with the CNT sensors embedded at the midplane showed no deterioration in strength. Multiple functionalities, including strain sensing and flow/UV cure monitoring during vacuum infusion are demonstrated. Sensors tested under flexural loading demonstrated sensitivity in tension and compression, and during resin infusion, the sensors could track resin flow and cure progression.

Silver-doped calcium silicate sol-gel glasses with a cotton-wool-like structure for wound healing

Skin has excellent capacity to regenerate, however, in the event of a large injury or burn skin grafts are required to aid wound healing. The regenerative capacity further declines with increasing age and can be further exacerbated with bacterial infection leading to a chronic wound. Engineered skin substitutes can be used to provide a temporary template for the damaged tissue, to prevent/combat bacterial infection and promote healing. In this study, the sol-gel process and electrospinning were combined to fabricate 3D cotton-wool-like sol-gel bioactive glass fibers that mimic the fibrous architecture of skin extracellular matrix (ECM) and deliver metal ions for antibacterial (silver) and therapeutic (calcium and silica species) actions for successful healing of wounds. This study investigated the effects of synthesis and process parameters, in particular sintering temperature on the fiber morphology, the incorporation and distribution of silver and the degradation rate of fibers. Silver nitrate was found to decompose into silver nanoparticles within the glass fibers upon calcination. Furthermore, with increasing calcination temperature the nanoparticles increased in size from 3 nm at 600 °C to ~25 nm at 800 °C. The antibacterial ability of the Ag-doped glass fibers decreased as a function of the glass calcination temperature. The degradation products from the Ag-doped 3D non-woven sol-gel glass fibers were also found to promote fibroblast proliferation thus demonstrating their potential for use in skin regeneration.

Numerical analyses on compaction behavior of nonwoven glass fiber fabric

In this study, thickness of single- and multi-layer nonwoven glass fiber fabric in dry and wet state was monitored during compaction and relaxation periods under a pressure range of 2 to 200 kPa. The results were numerically analyzed via power-law model and strain energy calculation. The compaction behavior of three-layer dry fabric stack showed the highest fitness to the power-law modeling. The findings of the power-law model revealed the lack of nesting between adjacent layers and showed that the repeated compaction/relaxation practice and the presence of resin significantly increased the fiber content. The outcomes of the model also indicated: (1) multi-layer fabrics tend to be compressed more easily than single-layer fabric (2) wet fabrics and relaxation periods display higher stiffening index than dry fabrics and compression periods, respectively. The compaction and relaxation curves tracing different paths pointed that some of the compaction energy was absorbed by the fabric. Thanks to the friction mechanism between layers, multi-layer fabrics absorbed more compaction energy (i.e. relaxed better) than single-layer fabric. However, the presence of the resin reduced the relaxation (i.e. the amount of absorbed compaction energy).

Chemical Modification on Woven Jute and Nonwoven Wet-Laid Glass Fiber Sheet Reinforced Poly-(<i>ε</i>-Caprolactone) Composites

High-moisture regains nature of cellulosic fibers considered one of the critical drawbacks for jute-based applications. To minimize this by developing better interfacial adhesion, a hydrophobic nonwoven wet-laid glass fiber sheet used the woven jute fabric in this experiment. For this purpose, woven jute fabric was categorized into untreated, silane, alkali, and alkali-silane combined treatment then compounded with the solution of polycaprolactone (PCL). Fabrication of composites performed the following sandwich method based on different hot-pressing time with temperature for detecting a prominent fabrication parameter. Surface treated jute fibers characterized using FTIR spectroscopy. Hence, the mechanical and thermal properties of composites were investigated to find the consequence of chemical treatments into woven jute fabric. Alkali-silane combined chemical treatments resulting in improved 48.38% of tensile strength over untreated optimized composites. Scanning electron microscope (SEM) used for displaying interfacial adhesion between fiber and polymer matrix. Besides, further investigation demonstrated due to the combined chemical treatment of alkali-silane optimized composites significantly enhanced the thermogravimetric (TGA) stability in contrast to other composites.

Retracted] Effect of the Reinforcement Phase on Indentation Resistance and Damage Characterization of Glass/Epoxy Laminates Using Acoustic Emission Monitoring

The effect of reinforcement phases on indentation resistance and damage behavior of glass/epoxy laminates was investigated in this research work. Woven glass fiber mat and nonwoven chopped glass fiber mat were used as fiber reinforcement phases for fabricating the laminates. Low‐velocity impact and quasi‐static indentation tests were performed on both laminates to investigate the contact behavior and energy‐absorbing capability. Moreover, the acoustic emission (AE) technique was employed to monitor the indentation damage resistance. AE parameters including normalized cumulative counts (NCC), normalized cumulative energy (NCE), rise angle (RA), and felicity ratio (FR) were analyzed. The bidirectional laminates showed premature load drops and drastic changes in the normalized cumulative counts/energy profile in the beginning of loading cycles, indicating the development of macrodamage such as debonding/delamination. AE sentry function results of bidirectional laminates show longer PII function at the earlier stages, associated with minor PIII function and greater PIV function, indicating the continuous degradation and progression of damage. In contrast, the chopped laminates exhibited superior postimpact performance than the bidirectional laminates. The presence of randomly oriented fibres prevents the delamination crack propagation during compression loading, which was attributed with the increased residual compressive strength.

Characterization of mesoscale inhomogeneity in nonwovens and its relevance in the filtration of fine mists

Structural properties in nonwoven materials, such as porosity and layer thickness, are typically spatially distributed on a micro- and mesoscale. The mesoscale inhomogeneity is visually perceived, inter alia, as the cloudiness of the nonwoven fabric or as inclusions in the bulk material. Differential box counting, which is a fractal based image analysis method, was used to assess the inhomogeneity of several wet laid nonwoven glass fiber filter media. It has been shown that the subjectively perceived extent of media inhomogeneity strongly correlates with the lacunarity of the analyzed image.The analyzed media were then tested in different configurations for their operating behavior in the filtration of oil mist. The inhomogeneity of a medium significantly affected the formation of liquid channels in the medium, more specifically the inhomogeneity of the media layer on the filter upstream side. As most droplets are deposited on the filter upstream side, liquid likely accumulates in regions of finer pore structure in the foremost media layer. Distinct oil channels that transport the coalesced liquid to the filter rear side subsequently form behind these regions. Homogeneous media that lack such regions show a depth-filter like increase of Δp before the formation of channels, i.e. the Δp curve shows an increasing gradient with filter loading, which then changes into a linear increase of Δp. When filtering at low velocities, the liquid distribution inside the media drastically changed from distinct channels to a conically tapering form towards the filter rear for a homogeneous medium and a system of many interconnected channels in an inhomogeneous medium.

Relevance of downstream support structure design for oleophilic and oleophobic oil mist filter operating performance

Coalescence filters in applications with high separation efficiency requirements, such as compressed air preparation, usually consist of several layers of nonwoven glass fiber media wrapped around a cylindrical metal support grid. The design of this grid has a crucial effect on gas flow inside the filter and therefore on droplet deposition and liquid transport inside the medium. Experimental studies were carried out with flat filter elements in combination with seven different downstream support grids to investigate the impact of the grids on operating behavior of the filters in oil mist filtration. The grids differed in open area fraction, perforation size and distance and were used in combination with either oleophilic or oleophobic filter media. It was found that the choice of the grid affects liquid transport mechanisms in the media, especially the film formation on the filter rear side of oleophilic filters, thus affecting total pressure loss in quasi-steady state, while impact was less significant for oleophobic media. Separation efficiency was not significantly affected by the choice of grid, while entrainment depended on film coverage of the filter rear side and open area fraction of the grid.

Mechanical properties of composite material laminates reinforced by woven and non-woven glass fibers

The purpose of this work is to study the mechanical characteristics in 3-point bending and in traction; static; and the impact behavior of three specimens of laminates made of glass fiber and polyester resin non-woven and woven, with the aim of using them in the repair of boat hulls and enhancing their value in the naval industry. Three types of laminates were developed by contact molding. These different specimens of laminates made of woven, non-woven and combined glass fiber (woven and non-woven) were subjected to mechanical tests (traction and 3-point bending). Analysis of the results of the tests carried out on these three types of laminate shows that one specimen stands out and gives higher mechanical performance than the othertwo.

Expression of Concern: Mechanical properties of composite material laminates reinforced by woven and non-woven glass fibers

Expression of Concern: Mechanical properties of composite material laminates reinforced by woven and non-woven glass fibers

Acoustic Emission from a Porous Non-Woven Fiberglass Material

Acoustic emission (AE) signals are studied for a porous non-woven glass fiber material subjected to both static and cyclic compression. An experimental set-up for the measurement of acoustic signals emitted from the porous solid during mechanical loading is described, and the interpretation of AE signal data is established in the context of scaling laws originally developed for the description of earthquakes. The analysis of micro-CT images before and after loading quantifies that fiber fracture is a predominantly associated with fiber fracture. Several prior studies have established the use of the Gutenberg-Richter and Omori scaling laws for the analysis of AE signals under static loading, but it is unknown if and how such approaches can be extended to cyclic loading. First, static fatigue experiments establish a baseline response of the porous glass fiber material. It is demonstrated that the Gutenberg-Richter and Omori scaling laws can be used to describe AE for the present material. Subsequently, it is shown that the Gutenberg-Richter law still holds under cyclic compression loading. However, the Omori law needs to be replaced. A new scaling law is proposed here which relates the density change in compression to the AE signal. Finally, a relationship between the AE signal statistics and the mechanical damage rate is established for the material at hand.

The influence of incorporation of silica and carbon nanoparticles on the mechanical properties of hybrid glass fiber reinforced epoxy

Recently, the study of hybrid nanocomposites has attracted much attention because they are highly expected for being used in many applications. In this context, there is an insisting need to investigate the effect of incorporation of silica and carbon particulates nanofillers into epoxy reinforced with woven and nonwoven tissue glass fiber. The influence of incorporation of silica (SiO2) and carbon black nanoparticles (C) with different weight fractions on the tensile properties, impact strength and fatigue performance of epoxy matrix reinforced with two types of E-glass fiber was investigated. The results showed an improvement in tensile properties, impact strength and fatigue life with addition of almost all nanoparticles contents considerably with respect to that of the neat glass fiber reinforced epoxy composites (NGFRE). Hybrid composites filled with 0.5 wt.% C exhibited the highest tensile strength and fatigue performance with an enhancement of 19% and 60% compared to NGFRE, respectively. An increase of 57% and 28% in tensile modulus and impact strength over NGFRE was obtained respectively with hybrid composites filled with 1 wt.% C. Adding 0.25 wt.% SiO2 and 0.25 wt.% C simultaneously showed an improvement in mechanical properties. SEM images of tensile and impact fracture surfaces are presented for CS 0.5 specimens which in turn reveal weak fiber/matrix interface.

3D Fabric/Polyurethane Foam Composites Containing Various Fabrics: Property Evaluations

In this study, different combinations of non-woven fabric, glass fiber fabrics, and carbon fiber woven fabrics are needle punched, and are then laminated with 3D fabrics. These materials are impregnated in a two-package PU blowing agent in order to form 3D fabric/PU foam composites. Bursting strength test, compression test, dart drop test, and sound absorption test are used to evaluate the effect of the skin fabrics on the properties of 3D/PU foam composites. The test results suggest that the skin fabrics containing nonwoven fabrics and carbon fiber woven fabrics have an optimal bursting strength of 4320.9 N. The skin fabrics that are composed of nonwoven fabrics and glass fiber woven fabrics have an optimal compressive strength of 15 MPa. The drop-weight impact test results indicate that skin fabric containing nonwoven fabrics and glass fiber woven fabrics have a residual stress of 540.8 N, moreover, this skin fabric also attain an optimal sound absorption coefficient of 0.9. Therefore, having composite fabrics as the skin layer is conducive for the mechanical properties and sound absorption coefficient of PU foam materials. In addition, the proposed 3D/PU foam composites can be mechanically reinforced, and the disadvantages of their constituent 3D fabrics can also be improved. The skin composite fabrics are adjustable for possible clinical applications, and provide the 3D/PU foam composites with diversity of applications, such as building materials and protective materials.

Improvement of Hardness and Wear Resistance of Glass Fiber-Reinforced Epoxy Composites by the Incorporation of Silica/Carbon Hybrid Nanofillers

ABSTRACTThe tribological performance of hybrid composite (epoxy reinforced with woven, nonwoven tissue glass fibers, silica and carbon black nanoparticles) was investigated. Two methods were used to ensure good dispersion of nanoparticles in epoxy resin which were ultrasonic processor and magnetic stirrer. The effect of silica and/or carbon black nanoparticle content on microindentation hardness and wear properties of the neat glass fiber-reinforced epoxy composites was investigated. The results from the wear test indicated that, under all applied loads, incorporation of silica and carbon black nanoparticles either single or combined significantly improved the wear resistance of neat glass fiber reinforced epoxy. A significant increase in hardness of the hybrid nanocomposite laminates was achieved. Analysis of variance was developed to study the optimal wear testing parameters on composite samples. The most significant parameter is the time, followed by nanoparticle (silica and carbon black) content.

Enhancement of water barrier properties and tribological performance of hybrid glass fiber/epoxy composites with inclusions of carbon and silica nanoparticles

Water barrier properties and tribological performance (hardness and wear behavior) of new hybrid nanocomposites under dry and wet conditions were investigated. The new fabricated hybrid nanocomposite laminates consist of epoxy reinforced with woven and nonwoven tissue glass fibers and two different types of nanoparticles, silica (SiO2) and carbon black nanoparticles (C). These nanoparticles were incorporated into epoxy resin as a single nanoparticle (either SiO2 or C) or combining SiO2 and C nanoparticles simultaneously with different weight fractions. The results showed that addition of carbon nanoparticles with 0.5 and 1 wt% resulted in maximum reduction in water uptake by 28.55% and 21.66%, respectively, as compared with neat glass fiber reinforced epoxy composites. Addition of all studied types and contents of nanoparticles improves hardness in dry and wet conditions over unfilled fiber composites. Under dry conditions, maximum reduction of 47.26% in weight loss was obtained with specimens containing 1 wt% carbon nanoparticles; however, in wet conditions, weight loss was reduced by 17.525% for specimens containing 0.5 wt% carbon nanoparticles as compared with unfilled fiber composites. Diffusion coefficients for different types of the hybrid nanocomposites were computed using Fickian and Langmuir models of diffusion. Copyright © 2017 John Wiley & Sons, Ltd.

Electromagnetic Evaluation of Multifunctional Composites for Use in Radar Absorbing Structures

The knowledge of how to process composite materials and combine them with radiation absorbing centers, using different components, additives and polymer matrices with suitable electromagnetic properties (dielectric constant and tangent loss), allows the production of multifunctional composites that can function as conductors or microwave absorbing materials. Thus, the purpose of this study was to process and evaluate the electromagnetic properties of multilayered multifunctional composites made with layers of glass fiber cloths or nonwoven glass fiber veils pre-impregnated with formulations based on carbon black. Electromagnetic properties of the multifunctional composites were evaluated by measuring the reflection of microwave radiation using the waveguide technique in the X-band (8.2 to 12.4 GHz). The results show that the multifunctional composites absorbed 90% to 99% of the energy of the incident microwave radiation. The high attenuation of the incident microwave radiation combined with their small thickness indicate that these multifunctional composites could be used in a number of military and civilian applications.

Nanocomposite polymer membrane derived from nano TiO2-PMMA and glass fiber nonwoven: high thermal endurance and cycle stability in lithium ion battery applications

A nano-composite polymer electrolyte membrane (NCPE) is made by introducing highly dispersed nano-TiO2 hybrid doped PVDF–HFP into a readily available nonwoven glass fiber.

Analytical determination of the effect of compression on the permeability of fibrous porous media

An existing geometric pore-scale model is geometrically adapted from an isotropic to an anisotropic structure in order to determine the effects of compression on permeability. In this analysis, streamwise compression is accounted for by incorporating the compression–porosity relationship into the analytical model, while permeability is expressed in terms of the fiber diameter and the pore-scale linear dimensions of the geometric model. The linear dimensions are determined from several required input characteristics, namely, the measured hydraulic pore diameters, the porosity, and the compression ratios. The proposed model is applied to determine the airflow through a compressed non-woven glass fiber filter, with results that are corroborated with experimental permeability data. The model is further validated against experimental permeability data for glass and nylon fibers as well as for airflow through a soft fibrous porous medium. Despite the simple model geometry, permeability predictions of the correct order of magnitude are obtained, with the significant effects of compression on permeability observed in the experimental data verified by these analytic permeability predictions.

Continuous unidirectional palmyra palm leaf stalk fiber/glass—polyester composites: static and dynamic mechanical properties

Various chemical treatments such as mercerization (alkali treatment), permanganate treatment, and benzoyl chloride treatment were performed on palmyra palm leaf stalk fibers. Composites were fabricated by hand layup method followed by compression molding process using unsaturated polyester as matrix. Two types of composites were fabricated, one by using treated continuous palmyra palm leaf stalk fibers and other by hybridizing nonwoven glass fiber mat and alkali treated continuous palmyra palm leaf stalk fibers with bilayer arrangement. In both the cases palmyra palm leaf stalk fiber is laid unidirectionally for composite fabrication. The composites were tested for its tensile, flexural, impact, and dynamic mechanical properties. There was an increase of 33% in tensile, 55% in flexural, and 50% in impact strength for benzoyl, permanganate, and alkali treated composites, respectively, compared to untreated fiber composites. But all the treated fiber composites did not show much variation in properties. Hybridization resulted in 54, 36, and 58% improvement in tensile, flexural, and impact properties, respectively, in comparison to unhybridized treated unidirectional palmyra palm leaf stalk fiber composites. Reinforcement of alkali treated fibers and hybridization of glass fibers enhanced the loss and storage modulus of the composites, increased glass transition temperature (Tg), and also reduced the tan δ peak. A positive shift in tan δ was also evident for all the composites.

Glass fiber coalescing filter media augmented with polymeric submicron fibers and modified with angled drainage channels

Glass fiber filter media are widely used in separation of droplets from liquid aerosols. In prior works two possible enhancements to the performance of the glass fiber media were studied: (1) the capture efficiencies were increased by augmenting the glass fibers with sub-micron sized electrospun polymer fibers, and (2) the pressure drop was decreased by modifying the filter media with insertion of 45° drainage channels. In this paper we report the simultaneous application of these two enhancements on the performance of the filter media.Filters were fabricated by inserting low surface energy woven polymer fiber drainage channels at various angles within non-woven glass fiber filter media augmented with Nylon sub-micron fibers. The effects of the presence and geometry of the drainage channels on the filter performance were evaluated experimentally. The sub-micron fibers gave the filter high coalescence and separation efficiencies while the drainage channels reduced the filter pressure drop. The micro glass fiber media augmented with 100nm Nylon fibers and modified with Polypropylene fiber drainage channels at 45° downward angles had the overall best performance.

Electrospun Superhydrophobic Poly(vinylidene fluoride-co-hexafluoropropylene) Fibrous Membranes for the Separation of Dispersed Water from Ultralow Sulfur Diesel

One of the major causes of diesel engine maintenance problems is water contamination in fuels. This paper discusses fabrication, characterization, and testing of non-woven glass fiber mats augmented with an electrospun layer of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) fibers for the separation of secondary water dispersions from ultralow sulfur diesel. The PVDF-HFP fibers had an average fiber diameter of 334 nm. All PVDF-HFP layers had water contact angles greater than 150° with relatively low hysteresis values, making them superhydrophobic. Water separation experiments showed that glass fiber media augmented with electrospun PVDF-HFP fiber mats significantly improved water separation, with water removal efficiencies reaching 99%, as compared to glass fiber media without the PVDF-HFP layer.