Characterization Of Composites Research Articles

Engineering a robust, multifunctional superhydrophobic/oleophobic microporous aluminum surface via a two-step chemical etching process

Surfaces with unique wettability properties are gaining attention for their widespread applications. Particularly, superhydrophobic surfaces, known for their remarkable water-repellent properties and low adhesion, have gained substantial interest in recent years owing to their versatile applications. Despite their versatile applications, the durability of such surfaces faces challenges like mechanical abrasion, chemical deterioration, and environmental factors, limiting their effectiveness in real-world scenarios. In this study, we successfully fabricated a mechanically robust, cost-effective, and easy-to-process superhydrophobic surface on an aluminum substrate using a two-step chemical etching process. Initially, the hierarchical microporous (HMP) structure was created through chemical etching, followed by the deposition of a self-assembled layer of PFOTS onto the fabricated aluminum substrate, attaining superhydrophobic and oleophobic properties. The surface exhibits remarkable superhydrophobicity with a water contact angle of 162°, while coupled with oleophobic characteristics against a wide spectrum of oils with surface tensions ranging from 21.5–63.3 mN m − 1. We conducted comprehensive characterizations of surface morphology and chemical composition, while also investigating the impact of surface morphology on wettability, physicochemical stability, and antibacterial properties. Mechanical testing revealed that the surface maintained its superhydrophobicity even after undergoing linear abrasion for a distance of 120 cm under an applied pressure of 12.25 kPa. Furthermore, the surface displayed self-cleaning, and anti-fouling, along with significant antibacterial properties against Staphylococcus aureus bacteria, creating a 23 mm zone of inhibition. We believe the proposed method will inspire the fabrication of large-scale superhydrophobic metallic surfaces endowed with multifunctional properties, making them highly suitable for a wide range of industrial applications.

In-situ fabrication and characterization of W-ZrC composites via pressureless reaction sintering

This research presents a study on the fabrication and characterization of tungsten‑zirconium carbide (W-ZrC), an ultra-high temperature ceramic, using an in-situ reaction sintering method. Tungsten carbide (WC) and zirconia (ZrO2) powders were used as precursors to synthesize composites with three different ratios. The thermodynamic phase stabilities of the precursor materials were analyzed, and the reaction products were determined based on the total pressure within the system. The fabricated composites were characterized by their microstructures, porosities, hardnesses, and thermal conductivities. The results show that the composites exhibited distinct crystal phases, including those of tungsten, tungsten carbide (W2C), zirconium carbide (ZrC), and tetragonal zirconia (t-ZrO2). The reaction pathways were determined based on the composition ratios and thermodynamic stability. The composites demonstrate good densification and interparticle bonding owing to the in-situ reaction sintering process, which simplifies the fabrication and lowers processing costs. The composites also exhibited desirable properties, such as high hardness and thermal conductivity (maximum 36.4 W·m−1·K−1), making them suitable for high-temperature applications. The findings of this study contribute to the understanding of the synthesis process and properties of W-ZrC composites and provide insights for their potential applications to industries such as aerospace, defense, and nuclear energy.

Axial Growth Characteristics of Optically Active InGaAs Nanowire Heterostructures for Integrated Nanophotonic Devices.

III-V semiconductor nanowire (NW) heterostructures with axial InGaAs active regions hold large potential for diverse on-chip device applications, including site-selectively integrated quantum light sources, NW lasers with high material gain, as well as resonant tunneling diodes and avalanche photodiodes. Despite various promising efforts toward high-quality single or multiple axial InGaAs heterostacks using noncatalytic growth mechanisms, the important roles of facet-dependent shape evolution, crystal defects, and the applicability to more universal growth schemes have remained elusive. Here, we report the growth of optically active InGaAs axial NW heterostructures via completely catalyst-free, selective-area molecular beam epitaxy directly on silicon (Si) using GaAs(Sb) NW arrays as tunable, high-uniformity growth templates and highlight fundamental relationships between structural, morphological, and optical properties of the InGaAs region. Structural, compositional, and 3D-tomographic characterizations affirm the desired directional growth along the NW axis with no radial growth observed. Clearly distinct luminescence from the InGaAs active region is demonstrated, where tunable array-geometry parameters and In content up to 20% are further investigated. Based on the underlying twin-induced growth mode, we further describe the facet-dependent shape and interface evolution of the InGaAs segment and its direct correlation with emission energy.

Preparation and Characterization of Composites Based on ABS Modified with Polysiloxane Derivatives.

In this study, organosilicon compounds were used as modifiers of filaments constituting building materials for 3D printing technology. Polymethylhydrosiloxane underwent a hydrosilylation reaction with styrene, octadecene, and vinyltrimethoxysilane to produce new di- or tri-functional derivatives with varying ratios of olefins. These compounds were then mixed with silica and incorporated into the ABS matrix using standard processing methods. The resulting systems exhibited changes in their physicochemical and mechanical characteristics. Several of the obtained composites (e.g., modified with VT:6STYR) had an increase in the contact angle of over 20° resulting in a hydrophobic surface. The addition of modifiers also prevented a decrease in rheological parameters regardless of the amount of filler added. In addition, comprehensive tests of the thermal decomposition of the obtained composites were performed and an attempt was made to precisely characterize the decomposition of ABS using FT-IR and optical microscopy, which allowed us to determine the impact of individual groups on the thermal stability of the system.

Enhancing mechanical performance of biodegradable automotive composites with EPO and graphene

Recent strides in composite manufacturing technology have sparked a widespread embrace of natural fiber composites in engineering applications, exemplified by flax fiber. The crux of this development centers on the creation of an environmentally friendly composite, utilizing alkali-treated flax fiber reinforcement and poly lactic acid (PLA) as the polymer matrix through a hot compression technique. The investigation into water absorption unveils that alkaline treatment augments the hydrophobic nature and enhances the crystallinity of flax fibers, resulting in improved adhesion between the reinforcement and polymer matrix. The introduction of 5% wt of epoxidized palm oil (EPO) as plasticizers not only counters brittleness but also elevates thermal stability. Further enhancements are achieved through the addition of 0.5 wt% of graphene nanoparticles as nano-fillers, culminating in superior mechanical properties. This research places a focal point on a thorough mechanical characterization of these green composites, encompassing tensile, flexural, and impact properties, along with an assessment of inter-laminar shear strength. A detailed analysis of dimensional stability is conducted, while morphological scrutiny is performed using scanning electron microscopy. This study marks a significant leap towards sustainable engineering, presenting innovative natural fiber green composites that exhibit heightened mechanical and environmental performance.

Review of alginate-based composites for 3D printing material

The ability of alginates to form hydrogel solutions makes them a promising biomaterial for three-dimensional (3D) printing. Researchers are investigating several techniques to improve the alginate hydrogels’ quality, such as using alginate-based nanocomposites as materials for 3D printing. This review examines the material of alginate-based composites, the printing technique, and the applications of 3D printing alginate-based composites. Material composites for 3D printing include alginate with clay, a combination of alginate with polymers or biopolymers, and a mixture of alginate with metal oxide and carbon. The 3D printing material from alginate combined with polymers is usually used in the medical and green packaging industries, whereas a mixture of alginate with clay, metal oxide, and carbon 3D printing material is utilized in the environmental field. When considering printing procedures, extrusion techniques are the most affordable. Furthermore, the purpose of alginate composite characterization is to determine the impact generated by the material combinations. This characterization is carried out based on the intended application. However, it is common to employ mechanical, thermal, rheological, scanning electron, XRD, and FTIR analysis to identify the fundamental characteristics of the alginate composite according to research.

High-throughput determination of accurate interdiffusivity matrices and atomic mobilities in fcc Co-Mn-X (X = Fe, Ni) alloys

In this paper, a series of terminal alloys were first prepared, undergoing microstructure and composition characterizations through a combination of X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA) techniques. Subsequent diffusion couple experiments were conducted to acquire initial concentration profiles in fcc Co-Mn-Fe and Co-Mn-Ni alloys. By leveraging experimental composition profiles from 12 groups of diffusion couples measured using EPMA, alongside the reported thermodynamic data, atomic mobility parameters within the fcc phase of the two ternary systems were accurately determined using HitDIC software. Employing the resulting kinetic databases, a comprehensive set of simulated data, including composition profiles and diffusion paths, was generated for all diffusion couples, demonstrating strong alignment with corresponding experimental results. Moreover, interdiffusivities spanning a wider composition range within the fcc phase of Co-Mn-Fe and Co-Mn-Ni systems were computed at different temperatures, shedding light on the diffusion behavior of alloy components in response to temperature and concentration fluctuations. Finally, drawing from the reported thermodynamic data and the currently matched atomic mobility parameters, overviews of the intricate relationships among diffusion-related properties and configurational entropy indicate that the endeavor to develop comprehensive thermodynamic and kinetic databases is essential for tailoring High-Entropy Alloys.

Physical, mechanical, and microstructural characterisation of tungsten carbide-based polymeric composites for radiation shielding application

Polymeric based composites have gained considerable attention as potential candidates for advanced radiation shielding applications due to their unique combination of high-density, radiation attenuation properties and improved mechanical strength. This study focuses on the comprehensive characterisation of polymeric based composites for radiation shielding applications. The objective of this study was to evaluate the physical, mechanical and microstructural properties of tungsten carbide-based epoxy resin and tungsten carbide cobalt-based epoxy resin for its efficiency in shielding against gamma-rays ranging from 0.6 up to 1.33 MeV. Polymeric composites with different weight percentages of epoxy resin (40 wt%, 35 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt% and 10 wt%) were fabricated, investigated and compared to conventional lead shield. The attenuation of the composites was performed using NaI (Tl) gamma-ray spectrometer to investigate the linear and mass attenuation coefficients, half value layer, and mean free path. High filler loadings into epoxy resin matrix (90% filler/10% epoxy) exhibited excellent gamma shielding properties. Mechanical properties, such as hardness were examined to assess the structural integrity and durability of the composites under various conditions. The fabricated composites showed a good resistance, the maximum hardness was attributed to composites with small thickness. The high loading of fillers in the epoxy matrix improved the microhardness of the composites. The distribution of the filler powder within the epoxy matrix was investigated using FESEM/EDX. The results revealed the successful incorporation of tungsten carbide and cobalt particles into the polymer matrix, leading to increased composite density and enhanced radiation attenuation. The unique combination of high-density, radiation attenuation, and improved mechanical properties positions polymeric based composites as promising candidates for radiation protection field.

Microstructure, mechanical characterisation and fractography of Al2214/3%Grp/x%B4Cp hybrid metal matrix composites

ABSTRACT This experimental investigation reports the impact of boron carbide (B4Cp) particles on Al2214/3%Grp/xB4Cp hybrid metal matrix composites (HMMCs) at a constant weight percentage of Grp (3 wt.%) and x wt.% of B4Cp particles (x = 1.5, 3, 4.5, and 6) produced by a conventional stir casting metallurgical route with bottom pouring facilities. The scanning electron microscope (SEM) combined with the energy dispersive X-ray spectroscope (EDX) shows reasonable uniform distributions of particles in the matrix phase, and a spectrum of elements present in hybrid composites with various intensities. The X-ray diffraction (XRD) analysis was performed for the phase characterisation of hybrid composites. Further, the mechanical properties of Al2214 alloy and Al2214/3%Grp/xB4Cp hybrid composites were studied. The experimental results of the hybrid composite revealed improved hardness and tensile properties with the addition of wt.% B4C particles. The tensile fractured surface (SEM) micrographs revealed the root causes and mechanisms of failures in hybrid composites.

BIODEGRADABLE POLYMER COMPOSITE BASED ON POLYVINYL CHLORIDE AND WOOD WASTE. DEVELOPMENT AND CHARACTERIZATION

This work deals with the development and characterization of biodegradable polymer composites based on of polyvinyl chloride (PVC) and wood waste (WW) post-consumer waste. Wood waste resulting from wood processing into finished products is cryogenically ground to min. 500 nm, mechanically functionalized at temperature with polydimethylsiloxane (PDMS) (7%) and compounded in varying proportions (10%, 20%, 50%). The new composite is biodegradable due to the compounding with wood fibers, have low density and implicitly the products made from, a lower weight, reduced costs and recover waste. Soles for shoes will be processed by injection using these materials.

Effect of incorporation natural fillers with Sterculia foetida fiber on physical, mechanical, and thermal characterization of epoxy polymer composites

Effect of incorporation natural fillers with Sterculia foetida fiber on physical, mechanical, and thermal characterization of epoxy polymer composites

Solution-Plasma Synthesis and Characterization of Transition Metals and N-Containing Carbon-Carbon Nanotube Composites.

Lithium-air batteries (LABs) have a theoretically high energy density. However, LABs have some issues, such as low energy efficiency, short life cycle, and high overpotential in charge-discharge cycles. To solve these issues electrocatalytic materials were developed for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which significantly affect battery performance. In this study, we aimed to synthesize electrocatalytic N-doped carbon-based composite materials with solution plasma (SP) using Co or Ni as electrodes from organic solvents containing cup-stacked carbon nanotubes (CSCNTs), iron (II) phthalocyanine (FePc), and N-nethyl-2-pyrrolidinone (NMP). The synthesized N-doped carbon-based composite materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). TEM observation and XPS measurements revealed that the synthesized carbon materials contained elemental N, Fe, and electrode-derived Co or Ni, leading to the successful synthesis of N-doped carbon-based composite materials. The electrocatalytic activity for ORR of the synthesized carbon-based composite materials was also evaluated using electrochemical measurements. The electrochemical measurements demonstrated that the electrocatalytic performance for ORR of N-doped carbon-based composite material including Fe and Co showed superiority to that of N-doped carbon-based composite material including Fe and Ni. The difference in the electrocatalytic performance for ORR is discussed regarding the difference in the specific surface area and the presence ratio of chemical bonding species.

Initiative to Increase the Circularity of HDPE Waste in the Construction Industry: A Physico-Mechanical Characterization of New Sustainable Gypsum Products

The annual production of plastic waste worldwide has doubled in just two decades, with approximately 390 million tonnes of plastic waste now being generated. In this context, the construction industry must move towards the development of new, more sustainable materials made under circular economy criteria. In this work, a physico-mechanical characterisation of gypsum composites with the incorporation of high-density polyethylene (HDPE) waste, replacing 2–4–6–8–10% by volume of the original raw material, has been conducted. The results show how the incorporation of these plastic wastes improves the water resistance of the gypsum material without additions, as well as producing a decrease in thermal conductivity and greater resistance to impact. On the other hand, it has been found that, as the percentage of recycled raw material added increases, the mechanical resistance to bending and compression decreases, leading to fracture due to a lack of cohesion between the matrix and the waste. Nevertheless, in all the cases studied, mechanical strengths higher than those established by the EN 13279-2 standard were obtained. Thus, the results confirm the viability of these secondary raw materials to be used in the development of new products for sustainable building, especially in the design of prefabricated panels for false ceilings.

Micromechanical modeling and experimental characterization of thermoplastic cork filler composites

This study focuses on the experimental characterization and micromechanical modeling of thermoplastic cork filler composites. The research investigates the influence of granule size on the mechanical properties of composites made with a polypropylene matrix and cork granulates. Tensile, compressive, flexural, and Charpy impact tests are conducted according to ASTM standards to assess the mechanical behavior of the Cork/Polypropylene composites with different size of cork granulates (2 mm, 0.5 mm and 50 μm). Additionally, a micromechanical model is developed to provide numerical insights into the composite’s mechanical properties. Results indicate that the use of smaller cork granules (50 μm) significantly enhances tensile, compressive, and flexural properties, while maintaining Charpy impact resistance comparable to the matrix material. The Young’s Modulus exhibits an augmentation of approximately 28%, the flexural modulus demonstrates a 10% increase, and the compressive modulus manifests a notable rise of 47.7%. One-way ANOVA analysis is employed to establish the statistical significance of granule size on the modulus. Numerical simulations reveal that the spherical morphology of fillers induces isotropic characteristics in cork composite materials.

Synthesis and characterization of polypyrrole composites: Optimization strategies for tailored material qualities and enhanced applications

Synthesis and characterization of polypyrrole composites: Optimization strategies for tailored material qualities and enhanced applications

Reuse of wood biomass ash to improve thermal behavior of gypsum plasters

Huge amounts of waste are generated each year in the world. In addition, the construction sector is one of the larger producers of residues and a huge energy consumer. Thus, architects, engineers and other actors of the building sector should give solutions in order to reduce that problem. In that sense, the idea of finding solutions for the end of the service life of materials, in order to promote circularity, has been studied by several researchers. In this study, biomass wood ash has been used as aggregate for the generation of new eco-efficient gypsum plasters, for its application in new buildings and rehabilitation works. In order to conduct an exhaustive characterization of the new composites, an experimental campaign of the plasters has been conducted: dry bulk density and thermal conductivity of the plasters have been measured. The results showed that it was possible to add up to 25% of wood ash without modifying the water/gypsum ratios. Moreover, thermal conductivity of the plasters has improved up to18% when the ash was added to the mixture. Finally, the effects of using the new gypsum composites in the thermal envelope of buildings was analyzed by its usage in a rehabilitation case study simulation.

Processing and characterization of high-performance thermoplastic composites manufactured by laser-assisted automated fiber placement in-situ consolidation and hot-press

Due to the short dwell time of processing temperature and pressure, the quality of the composite manufactured by AFP was not equal to the traditional processing method like autoclave or hot-press. Deeply understanding the mechanism of differences was conducive to improving the performance of the composite manufactured by AFP. In this study, the properties of high-performance carbon fiber reinforced polyphenylene sulfide (CF/PPS) thermoplastic composites manufactured by laser-assisted automated fiber placement (LAFP) in-situ consolidation and hot-press was characterized and compared. The temperature history of LAFP in situ consolidation indicated that the heating and cooling process occurred during a few seconds. And the crystallinity was only 21.6% for the laminate from LATP, while the void content was 2.75%. Due to the low crystallinity, high void content and low interlaminar bonding, the ILSS of the laminate from LAFP in situ consolidation was 34.9% lower than that of hot-press. However, the mode Ⅰ fracture toughness was 103.7% higher than hot-press.

Effect of tapered natural fiber on elastic properties of sisal fiber-reinforced composite: An experimental and micromechanics approach

In the characterization of natural fiber-reinforced composites, it is crucial to consider the nonuniform cross-section of fibers extracted from plants or leaves, which results from the inherent variation in fiber diameter. This variation is a key aspect of the actual reinforcement behavior, and disregarding it by assuming a uniform cross-section can violate the physical understanding of the composite’s mechanics. This study focuses on characterizing the elastic properties of a natural tapered sisal fiber-reinforced epoxy composite, taking into account the variation in fiber diameter along its length. To achieve this, both experimental, analytical, and micromechanics methods are employed. The experimental approach involves conducting tests to measure the mechanical properties of the composite, while the micromechanics analysis provides a framework to understand the reinforcement behavior and predict the composite’s mechanical response. The study aims to identify and present various elastic properties of the composite, including the longitudinal modulus, transverse modulus, in-plane and out-of-plane shear modulus, and major and minor Poisson’s ratios. The fiber taper angle has a significant effect on longitudinal and transverse modulus and interfacial stresses. The longitudinal modulus experiences a reduction of 25.9% when increasing the taper angle from [Formula: see text] to [Formula: see text] at a higher fiber volume fraction (40%). However, at a lower volume fraction of the same fiber (10%), the reduction in modulus is limited to 5.74%. Similarly, the transverse modulus is also affected by the taper angle. At the higher fiber volume fraction, there is a decrease of 24.52%, whereas at the lower volume fraction and higher taper angle of the fiber, the decrement is 4.94%.

Magnetic polymeric composites: potential for separating and degrading micro/nano plastics

The pervasive presence of microplastics (MPs) and nanoplastics (NPs) across various ecological settings, organisms, and products has underscored the urgent need to collect data on their abundance and identify the polymer types in diverse substrates. NPs distinguish themselves from MPs by their smaller size. The application of magnetic composites in wastewater treatment has grown in popularity due to their remarkable flocculation capabilities and ferromagnetic properties. This comprehensive review centers on the synthesis methods, preparation technologies, and practical applications of magnetic polymeric composites for separating and degrading MPs/NPs. It offers an extensive overview of recent advancements in the separation and degradation of MPs/NPs within various wastewater sources. The review begins by consolidating efficient methods for the separation of MPs/NPs. This includes techniques such as adsorption, coagulation/flocculation, flotation, filtration, and magnetic separation. The subsequent section explores diverse approaches for the degradation of MPs/NPs, encompassing advanced oxidation processes (AOPs), electrochemical degradation, photocatalysis, and biological degradation. Additionally, the review offers in-depth insights into the synthesis and characterization of magnetic polymeric composites. Lastly, it discusses the current challenges and prospects associated with the separation and degradation of MPs/NPs in wastewater treatment.

Mechanical properties and wear characterization of Al-Mg composites synthesized at different temperatures

<abstract> <p>Reactive sintering of Al-Mg powder mixtures containing 5, 10, 15, and 20 wt.% Mg was used to synthesize lightweight composites reinforced with in-situ formed Al<sub>3</sub>Mg<sub>2</sub> and Al<sub>12</sub>Mg<sub>17</sub> intermetallics. Detailed microstructural investigation and phase analysis were employed to examine the phases in the composites formed at 400 and 450 ℃. The creation of particles with the Al<sub>12</sub>Mg<sub>17</sub> cores encapsulated by the Al<sub>3</sub>Mg<sub>2</sub> phase, which was further covered by a continuous aluminum matrix, was observed in the composites synthesized at 400 ℃. If the composites were held at 450 ℃, the liquid phase appeared at the Al-Mg interface, and as a result, a two-phase mixture was formed. It was the eutectic composed of the Al<sub>3</sub>Mg<sub>2</sub> intermetallic compound and a solid solution of magnesium in aluminum (Al). The introduction of magnesium particles into the aluminum matrix resulted in a decrease in the density of composites, but there was no significant difference in the density of composites sintered at different temperatures. The mechanical behavior of the composites was examined using microhardness and hardness measurements and a room-temperature compression test. The result of using different cooling speeds, with the furnace and quenching in water, was the refining of the grains in the Al<sub>3</sub>Mg<sub>2</sub> + (Al) eutectic, resulting in an increase in microhardness. The increase in hardness of the composites was related to the amount of particles introduced. Sintering at 450 ℃ and the cooling method influenced the hardness and compressive strength of the composites, which were higher by 10% and 13%, respectively, compared to composites sintered at 400 ℃. Tribological tests showed that introducing more and more magnesium particles into the aluminum matrix, followed by reactive sintering, increased the wear resistance. On the other hand, the sintering temperature and cooling conditions had little effect on the wear resistance of the Al-Mg composites.</p> </abstract>