Materials Glass Research Articles

Modeling of a Broadband Microwave Composite Thin Film Absorber.

Composite thin film absorbers show superior performance and have a wide range of applications. Obtaining a broadband composite thin film absorber is a challenge. In this work, we proposed a modeling of a broadband microwave composite thin film absorber based on the impedance matching theory and equivalent circuit model of the square loop. The unit cell of the absorber was composed of metal square loops with high magnetic conductivity deposited on the polyethylene substrate, and an FR-4 (epoxy glass cloth) substrate was the spacer substrate layer. The simulation results show that the absorptivity of the absorber reached more than 90% in the frequency range of 8.7-18 GHz for TE and TM waves under normal incidence. The thickness of the designed absorber was 2.05 mm (0.059 λmax, λmax corresponds to the maximum absorption wavelength). The simulation results show that the energy distribution in the proposed absorber was mainly localized in the top metal FSS layer due to the ohmic loss of metal, and the dielectric loss played a small role in the absorption of the absorber. Our work provides a design approach to improve the efficiency of optoelectronic devices and thermal detectors and has application prospects in radar and aircraft stealth applications.

Acoustic behavior of three-dimensional woven fabrics and their composites: role of fiber type and weave architecture

The ability of composites to insulate against noise and heat is crucial when utilized in buildings and other public structures and provide enhanced load bearing properties. Three-dimensional (3D) woven textile structural fabric and composites are one of the least investigated. Therefore, in this research, the acoustic behavior of various woven structures was investigated. The effect of weave geometry, weave architecture, number of stuffer layers, etc. on the acoustic behaviors of 3D woven orthogonal fabrics was studied. The textile reinforced composites were also characterized for tensile properties. The acoustic performance of the woven fabrics also depends on the air porosity in the structure. Therefore, investigation of air flow resistance and its correlation with sound absorption coefficient is very essential. It was observed that the acoustic behavior of jute and flax orthogonal fabrics is superior to glass fabrics. Fiber-reinforced composites show less sound absorption characteristics due to the infusion of epoxy resin.

Asphaltene-Derived Graphene Quantum Dots for Controllable Coatings on Glass, Fabrics, and Aerogels.

Graphene quantum dots (GQDs) derived from natural asphaltene byproducts can produce controlled hydrophobic or hydrophilic interfaces on glass, fabrics, and aerogels. A set of facile solvent extraction methods were used to isolate and chemically prepare materials with different surface functionalities from a commercially derived asphaltene precursor. The organic-soluble fraction was used to create hydrophobic and water-repellent surfaces on glass and cotton fabrics. The GQD solutions could also penetrate the pores of a silica aerogel, rendering it hydrophobic. Alternatively, by extracting the more polar fraction of the GQDs and oxidizing their surfaces, we also demonstrate strongly hydrophilic coatings. This work shows that naturally abundant GQD-containing materials can produce interfaces with the desired wettability properties through a straightforward tuning of the solvent extraction procedure. Owing to their natural abundance, low toxicity, and strong fluorescence, asphaltene-derived GQDs could thus be applied, in bulk, toward a wide range of tunable surface coatings. This approach, moreover, uses an important large-scale hydrocarbon waste material, thereby offering a sustainable alternative to the disposal of asphaltene wastes.

Development of Fiber Sensors integrated with Aerospace Composites for Structure Health Monitoring

The wide-spread use of composite material in aircraft across the world is expected to create a big need to improve structure health monitoring (SHM). Optical fiber sensors offer more advantages than conventional sensors, such as light weight, small size, immune to electromagnetic interference, easily embedded in composites. Extensive applications have been reported with a few embedded technology details by Boeing and Airbus, etc. In this paper, The methods of improved optical fiber surface-bonded composites by glass cloth and epoxy resin, as well as optical fiber embedded in composites were researched. The installation of fiber and composites, composites assembly pressure adaptability on FBG sensors, influences on structure properties of composite materials due to different fiber diameters and different numbers of optical fibers by the way of microscopic interface analysis and C-san were studied. The adequate fiber embedded technology was found to obtain the most feasibility of SHM. Light intensity and wavelength of FBG sensor surface-bonded by glass cloth are affected by the structural assembly pressure. It can be seen that diameter of embedded optical fiber equal to the thickness of prepreg monolaye, the fiber embedded next to 0 degree layer, less than five fibers within a 25mm width composite unit have little impact on composite structure. Then, 12 FBG sensors were embedded in a typical aircraft structure, a carbon fiber enhanced stiffened composite plate with length 600 mm and width 600 mm, to detect position and energy of external impact load by a mathematical analysis method, cross correlation algorithm. Finally, suggestions on future study are listed from four aspects, co-forming technology of FBG sensor and composite skin, research on the extraction technology of optical fiber, new flexible wing testing technology and advanced fiber optical sensing technology.

Selective extraction of phospholipids from human milk using glass fabric modified with zirconium-based metal organic framework

Phospholipids (PLs) are important and complex trace lipids in milk, which have positive effects on the infants' nervous and immune system development. Herein, a new method for selective extraction of PLs using glass fabric @ MOF-808 was proposed. Based on Lewis acid-base interaction, MOF-808 containing abundant Zr-OH groups was selected as the adsorption body, and glass fabric was used as a substrate to make the adsorbent easy to remove and reuse. The influencing factors such as loading solution, extraction time, eluent and elution time were further investigated. The adsorbent showed high adsorption capacity (3.31–6.54 mg/g for PLs) and good reusability (reused at least five times). The method showed low detection limits (1.61 μg/L - 10.24 μg/L) and quantification limits (5.24 μg/L–51.21 μg/L) for eight classes of PLs. The analysis of PLs in human milk at different lactation stages by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry could obtain up to 206 PLs, indicating that the method has extremely high extraction and anti-interference capabilities. This work is the first time to introduce MOF materials to selectively extract PLs and use glass fabric as a substrate for MOF-808, which has the advantages of easy recovery and high sensitivity. It provides technical support for the discovery of more PL species and has potential applications in phospholipidomics.

Engineering the Tensile Response of Glass Textile Reinforced Concrete for Thin Elements

Textile-reinforced concrete (TRC) is a composite made with bi-directional non-metallic fabric embedded in a fine-grained cementitious matrix. When engineered appropriately, these composites can reduce material usage for the desired performance, resulting in slimmer sections and enhanced material efficiency, which in turn lowers the CO2 footprint. To facilitate the widespread application of TRC in practice, it is crucial to comprehend the material and structural behavior of these composites, which can pave the way toward an optimized design methodology. In this paper, the tensile response of TRC is studied with different textile geometries, volume fractions and matrix strengths. The influence of the coating impregnation on the effectiveness of the textile to enhance the response of the composite is discussed, with complementing evidence from microstructural observations. The results of tests with different textile configurations indicate a transition in the type of stress–strain response from tri-linear to bi-linear, beyond a certain effective volume fraction. The paper also presents a simplified model to predict the bi-linear response from the efficiency factor-based approach. The insights gained can assist in achieving composite designs with optimized sections and limited tensile stress cracking, ensuring the targeted performance in slender elements.

A Study on the Effect of Gamma-Radiation on the Molecular Structure and Hydrophobic Properties of Telomeric Coatings on Glass Fabric

A Study on the Effect of Gamma-Radiation on the Molecular Structure and Hydrophobic Properties of Telomeric Coatings on Glass Fabric

Experimental evaluation of the durability of glass Textile-Reinforced concrete

Textile reinforced concrete (TRC) is a promising alternative to conventional steel-reinforced systems, especially for slender, lightweight structural and nonstructural applications. One of the critical parameters to be accounted for in the design of these composites is their long-term mechanical performance, especially the reduction in tensile capacity with time. This paper looks at the influence of aging on the response of textiles and composites with AR- and E-glass fibers. Six coated glass textiles were exposed to three alkaline solutions with different pH ranges. Accelerated aging of the composites with these textiles was carried out with the hot water immersion method at 50 °C, and the reductions in tensile strength are compared with the results from the natural aging of composites over 4 years. Two matrices were used in the studies to identify the improvements due to lower water/binder ratio and matrix porosity. The change in the morphology of fibers and coating after exposure is discussed with observations from scanning electron microscopy (SEM). The type and extent of textile coating have a profound influence on the residual strength of the composite. The composites with higher strength matrix showed better retention of strength. The trend of degradation in alkaline exposure, accelerated and natural aging is discussed with the comparison of the deterioration mechanism observed from microstructural studies in each case.

Electrothermal Atomic Absorption Determination of Platinum and Palladium in Glass Cloth Catalysts

Electrothermal Atomic Absorption Determination of Platinum and Palladium in Glass Cloth Catalysts

Enhancing slender reinforced concrete columns with G-FRCM jackets: Experimental and numerical analysis of confinement effects and cross-sectional shape impact

This research investigates the use of Glass Fabric Reinforced Cementitious Matrix (G-FRCM) as a confinement material for slender reinforced concrete (RC) columns with slenderness ratios greater than the slenderness criterion for isolated members. An experimental program was conducted on six slender RC columns, including two control and four G-FRCM-confined specimens. The results demonstrated that the G-FRCM strengthening strategy was highly effective, with the compression resistance of the columns increasing by 22.1% and 55.5% for one and two layers of G-FRCM, respectively, compared to the control samples. The experimental results were used to implement and validate the non-linear behaviour of G-FRCM-confined RC columns, employing the Finite Element Method (FEM) through the ABAQUS software. The results, in terms of compression strength, were consistent compared to the experiments, with a difference of less than 5%. Additionally, a parametric investigation has also been conducted to analyse the influence of the slenderness ratio on the response of confined columns. The findings of this study contribute to the understanding of the use of G-FRCM as a highly effective confinement material for RC columns.

Thermoset-polymer matrix composite materials of jute and glass fibre reinforcements: Radiation effects determination

In this work, woven jute and glass fabrics were used as natural fiber and synthetic fiber reinforcements, respectively, and unsaturated polyester resin was used as a thermoset polymer matrix to fabricate jute/polyester and glass/polyester composites via compression molding. As expected, glass/polyester exhibited superior performance than jute/polyester composites in terms of mechanical properties and moisture uptake behavior. Further, both composite laminates were exposed to gamma (γ) irradiation at a dose of 5 kGy to enhance their performance. After γ-irradiation, it was revealed that tensile strength, bending strength, tensile modulus, bending modulus, and impact strength increased by approximately 14, 28, 20, 21, and 13%, respectively, for the case of jute/polyester composites while glass/polyester composites demonstrated 13, 27, 15, 14, and 22% increase of the values, respectively. Further characterization of the composite samples was performed via moisture uptake in water and salt solutions, Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrum (EDS) analysis.

A Study on the Effect of Gamma-Radiation on the Molecular Structure and Hydrophobic Properties of Telomeric Coatings on Glass Fabric

Coatings of aluminoborosilicate fabric have been obtained by deposition from solutions of radiation-synthesized tetrafluoroethylene telomers. The resulting coatings were characterized by IR spectroscopy. By the sessile drop method, it has been established that the surface of the coatings is hydrophobic with a water contact angle of 140°. The effect of gamma-radiation on the molecular structure of coatings has been examined using IR spectroscopy. It has been shown that irradiation of the studied samples in air results in the formation of terminal COOH groups, which worsen the hydrophobicity of the samples. Irradiation in vacuum does not affect the hydrophobic properties of telomeric coatings

Tensile behavior of high-performance interlayer hybrid composites of polypropylene and glass fiber for civil engineering

Traditional interlayer fiber reinforced polymer (FRP) composites utilized in civil engineering are deficient in either the sufficient stiffness or ductility. For this, a study was conducted on the tensile behavior of interlayer hybrid FRP composites, which were composed of polypropylene (PP) and glass fabrics with an epoxy resin as the matrix and a central layer of glass fabric. This paper presents the design concept, failure mode, and constitutive model for glass/PP FRP composites. The experimental results indicate that the glass/PP FRP composites exhibit higher stiffness and ductile compared to traditional FRP composites, thereby demonstrating superior mechanical properties. Moreover, the finite element (FE) method was employed to identify all potential failure modes of glass/PP FRP composites, and it was concluded that only delamination failure mode is applicable in civil engineering. Based on the FE results, a failure mode map was generated for glass/PP FRP composites, which can facilitate rapid identification of its failure modes. To quantify the tensile behavior of these composites, a two-limit tensile constitutive model was developed. Considering that composites are typically designed for tension, the research presented in this paper can offer theoretical support for the implementation of glass/PP composites in civil engineering applications.

Mechanical Performance of Glass/Epoxy Composites Loaded with Silane-Treated Aluminum Hydroxide Fillers.

This study investigates the influence of silane-treated aluminum hydroxide on the mechanical performance of flame-retardant composites. These composites have potential applications for luggage bags, as a replacement for conventional plastics, offering more durability and lighter weight. Glass fabric was used as the reinforcement, while epoxy was used as the matrix material. To impart flame retardancy, aluminum hydroxide nanoparticles were used as fillers in different weight % age (5%, 10% and 15%). As these are inorganic particles and have compatibility issues with the matrix material, silane-coupling agents (Dynasylan® 6490 and Dynasylan Glymo) were used to treat these filler particles. Both the silane-coupling agents fraction used for treatment and the fillers fraction added to the composites were varied to determine the most optimum combination. The mechanical properties of the developed composites such as tensile, flexural, and short beam shear strength were investigated. The best results were exhibited by 10% aluminum hydroxide fillers treated with 1% (by weight) coupling agent (Dynasylan Glymo).

Insights into the large‐size graphene improvement effect of the mechanical properties on the epoxy/glass fabric composites

AbstractIn this study, we investigated how the chemical structural properties, mechanical properties, and morphology of large‐size graphene platelets (LGPs) doped glass fabric (GF)/epoxy composites are affected by varying loading amounts of LGPs. Scanning electron microscope results revealed that the dispersion and filling effect of LGPs can improve the flowability of the resin, reducing the aggregation and shrinkage of the resin on the glass fabric surface, thereby facilitating better resin infiltration and coverage of the glass fabric surface. From the spectrum analysis, the binding of LGPs with epoxy resin was the physical combination, without new chemical groups generated during the curing process. The addition of LGPs improved the ratio of the crystalline phases in the composites, from 30.00% of the GF/epoxy to 57.50% of the GF/epoxy@2.2LGPs. Mechanical properties indicated that the composites exhibited greater tensile strength than pure GF, which progressively increased with increasing LGPs content until it reached 1.5 wt%, then the tensile strength starts to decrease. And the GF/epoxy@1.5 LGPs exhibited 136% enhancement in tensile strength compared to other carbon fillers reinforced composites, which achieved a satisfactory enhancement under relatively low loading content.Highlights The effect of the large‐size graphene platelets (LGPs) on the properties of glass fabric (GF)/epoxy composites. Compared to the glass fabric/epoxy composite, the LGPs doped composite possessed a much higher storage modulus (E′). The LGPs doped composite exhibited 136% enhancement in tensile strength compared to other carbon fillers reinforced composites. The addition of LGPs improved the ratio of the crystalline phases in the composites.

Strength analysis of marine biaxial warp-knitted glass fabrics as composite laminations for ship material

Abstract Fiberglass-reinforced plastics (FRP) composite materials for ships that are widely used are marine-grade unsaturated polyester resin matrix and combimat fiber, a combination of marine-grade chopped strand mat (CSM) and woven roving (WR) fibers. Although less popular than marine CSM–WR, marine biaxial warp-knitted glass fabrics have the potential to be applied as fiber laminates for ship hull materials. A comparative study of tensile and bending strength between marine CSM–WR composite and marine CSM–biaxial composite had been conducted. All composites met the criteria of the Indonesian Classification Bureau. Specifically, the CSM–biaxial had higher tensile and flexural strength with fewer laminations than the CSM–WR. Laminate type II had the highest average normalized tensile and flexural strength, 186.1 and 319.2 MPa. A layer of biaxial fiberglass had a very significant effect on tensile and flexural strength. Besides its strength, fewer type II laminations can speed up the production process of FRP ship hulls. Furthermore, the CSM–biaxial composite had relatively high normalized flexural strength compared to other references. However, the normalized tensile strength achieved in this study was at an intermediate level compared to other references.

MWCNT-Coated Glass Fabric/Phenol Composite Heating Panel Fabricated by Resin Infusion Process.

MWCNTs (multiwalled carbon nanotubes) were applied to fiber-reinforced composite materials with phenolic resin having flame retardance for the composite heating panels of railroad vehicles. Instead of dispersing MWCNTs in the matrix, the surface of a pristine plain-weave glass fiber fabric was coated with MWCNTs through a series of dip-coating and drying processes, followed by the resin infusion of the phenolic resin to make the composite heating panel. Before and after the resin infusion process, low percolation thresholds of 0.00216 wt%MWCNT (weight percent of MWCNTs) and 0.001 wt%MWCNT, respectively, were achieved, as were very high electrical conductivities of 47.5 S/m at 0.210 wt%MWCNT and 26.7 S/m at 0.116 wt%, respectively. The low threshold and high conductivity can be attributed to the formation of electrical pathways directly onto the glass fabrics. It was confirmed that mechanical properties such as modulus, strength, and maximum strain were at the same level as those of the pristine glass fabric composite. The heating performance with temperature uniformity, as well as the electrical and mechanical properties, indicates that the resin-infused glass fabric composite having MWCNTs directly coated onto the fabric surface can be a solution for lightweight structural composite heating panels for railway vehicles.

Solid particle erosion and scratch behavior of novel scrap carbon fiber/glass fabric/polyamide 6.6 hybrid composites

AbstractThis study investigated the tribological performance of hybrid composites composed of scrap carbon fiber (CF), glass fabric (GF), and polyamide 6.6 (PA6.6) through an innovative approach for reusing scrap CFs in high‐value composite structures. The experimental setup included CF/GF/PA6.6 hybrid composite laminates with varying CF contents and surface‐modified GFs, as well as PA6.6 sheets and GF/PA6.6 composite laminates. Solid particle erosion and scratch tests were conducted to assess the influence of scrap CF hybridization and GF surface modification on the tribological properties of the composites. The results demonstrated that neat PA6.6 sheets exhibited the lowest erosion rate, while the incorporation of CF and GF reinforcements had a detrimental effect on erosion resistance. The highest erosion rate was observed within the impact angle range of 15°–30° for pure PA6.6 sheets, whereas for composite laminates, it occurred within the range of 30°–45°. In contrast, CFs positively affected scratch hardness despite their negative impact on erosion resistance. Additionally, the silane treatment of GFs, which enhanced interfacial strength, improved the erosion resistance and scratch hardness of GF/PA6.6 composite laminates without CF. Profilometer‐based topographic analysis revealed a correlation between the average surface roughness of the eroded surfaces and the weight loss resulting from solid particle erosion.

Design and Manufacturing of a Hexapattern Frequency Selective Surface Absorber for Aerospace Stealth Application.

Integrated frequency selective surface (IFSS) absorbers with larger bandwidth, effective reflection loss, polarization-insensitive characteristics, angular stability with compact/thin design, and ease of fabrication have captivated significant importance in stealth technology. Herein, we report on an IFSS absorber that has been designed, simulated, and implemented for manufacturing to achieve effective stealth properties. Initially, frequency selective surface (FSS) layers have been designed that comprise a closed centroid honeycomb structure surrounded with four annular hexagonal rings, splitted, alternatively, and enveloped with four L-shaped elements. The simulated pattern has been optimized on glass fabric for reflection loss (RC, dB) at a thickness of ∼0.1 mm by choosing sheet resistance of pattern 110 Ω/□. A FSS layer combined with interlayer lossy dielectric laminates (1.8 mm) and a carbon-fabric-reinforced-plastic ground has been simulated as an IFSS absorber. The performance of RC, in normal and angular configuration (0-60°), under transvers an electric/magnetic mode of polarization, including analysis of the displacement current, volume power loss distribution, and complex admittance has been carried on IFSS. Subsequently, the proposed absorber has been fabricated using customized carbon-based resistive ink imprinted on glass fabric by mask lithography compounded with laminates (a carbon black powder/epoxy composite) and ground. Their manufacturing details, including free space and anechoic chamber RC measurements, have been presented. The simulated and experimental RC performances of the absorber are found to be in good agreement, possessing minimal 10 dB reflection loss (90% absorption) with a sample thickness of 1.9 mm (0.05λL, where λL corresponds to a lower operating frequency), covering 76% fractional bandwidth in X and Ku bands. The proposed design architecture of the IFSS is ideally suitable for aerospace stealth platforms.

Characterising the shear resistance of a unidirectional non-crimp glass fabric using modified picture frame and uniaxial bias extension test methods

The forming behaviour of a unidirectional non-crimp fabric (UD-NCF) consisting of polyamide stitches with a tricot-chain stitching pattern is explored. Notably, there are no stabilising tows orientated transverse to the main tow direction in this fabric, a common feature in many ‘quasi’ UD-NCFs, this allows extension of the stitch in the transverse direction under certain loading conditions. The lack of stabilising tows introduces a possible low-energy deformation mode to the UD-NCF, which is absent in biaxial fabrics and to a large extent in ‘quasi’ UD-NCFs. The in-plane shear behaviour is initially investigated using both standard ‘tightly-clamped’ picture frame tests and uniaxial bias extension tests. Preliminary results show a dramatic difference in results produced by the two test methods. During the picture frame test, fibres can be subjected to unintended tension due to sample misalignment in the picture frame rig. To mitigate error arising from this effect, the picture frame test procedure is modified in two different ways: by using an intentional pre-displacement of the picture frame rig, and by changing the clamping condition of test specimen. Results show that the modified picture frame test data contain less error than the standard ‘tightly-clamped’ test but also that the shear stiffness of the UD-NCF is notably lower when measured in the bias extension test compared to the picture frame test, mainly due to the difference in loading conditions imposed during the two tests.