Properties Of Composite Materials Research Articles

Effective thermal and electromagnetic properties of composite materials containing ellipsoidal-coated fillers oriented randomly

This study aims to derive explicit solutions for the effective thermal and electromagnetic properties of composite materials containing coated fillers oriented randomly. In this study, the coated fillers are modeled as double inhomogeneous inclusions with anisotropic properties and ellipsoidal shapes, without loss of generality. This model is analyzed by combining the double inclusion method with the self-consistent method or the Mori–Tanaka method. The derived solutions for the effective properties are expressed in explicit form by the physical properties of constituents and the difference in shape between the inner and outer regions of the coated fillers, and confirmed to be consistent in the limit of no coating layer. In addition, the solutions of effective properties are also derived for composite materials containing many kinds of coated fillers with different shapes and physical properties. The solutions allow the prediction of thermal conductivity, permittivity, electrical conductivity, and magnetic permeability of a wide range of composite materials by analogy with thermal and electromagnetic properties. These solutions are applied to the following two composites: diamond fillers coated with TiC/Al, and Co fillers coated with Co 3 O 4/Mg. The effect of the thickness of the coating layer on the effective thermal conductivity of these materials is investigated. As a result, our analytical results for these composite materials generally agree with the experimental results. Moreover, from the viewpoint of maximizing the thermal conductivity of diamond fillers coated with TiC/Al, the optimal combinations of the thickness of the coating layer and the shape of the diamond fillers are identified. For Co coated with Co 3 O 4/Mg, we find that the shape of Co fillers should be long fibrous from the viewpoint of giving high magnetic permeability while maintaining high thermal conductivity due to Mg. Thus, the analytical solutions are demonstrated to be powerful tools for designing composite materials containing coated fillers.

Promoting Cross-Link Reaction of Polymers by the Matrix-Filler Interface Effect: Role of Coupling Agents and Intermediate Linkers.

The matrix-filler interface effect plays an important role in determining the structural stability and mechanical properties of polymer composite materials, which remain ambiguous and need to be studied. The network-forming dynamics of poly(3,3-bis (azidomethyl) oxetane-tetrahydrofuran) (PBT) at the ammonium perchlorate (AP) surface was studied by using atomistic molecular dynamics simulation, considering the additives of curing agent toluene diisocyanate (TDI), cross-linker trimethylolpropane (TMP), and coupling agent triethanolamine (TEA). The presence of the AP surface promotes chain cross-link reaction, which is attributed to the increased production of intermediate linkers formed by TDI, TMP, and TEA. The intermediate linker has three reactive sites that can react with PBT main chains to form a cross-linked structure. Owing to the strong interaction with the AP surface, the coupling agent TEA plays a dominant role in forming the intermediate linker. At the early stage of network forming (reaction ratio r < 30%), the AP surface adsorbs TEA, which leads to a maximum contact density to PBT. As r increases to 60%, the density of intermediate linkers near the AP surface reaches a maximum value. Consequently, the chain cross-link reactions between the intermediate linker and PBT main chains are enhanced as r > 60%. This work explains the micromechanism of the promotion of chain cross-link reaction by the interface effect and provides important insights on designing polymer materials with high mechanical properties.

Comparative Study of the Mechanical Properties of a Novel Epoxy Composite Material Reinforced by Bidirectional Woven Carbon Fabric and Hybrid Kevlar/E-Glass

The objective of this work is to carry out a comparison of different materials in the form of a bidirectional carbon fabric and hybrid Kevlar and glass as reinforcements in an epoxy matrix with a loading rate of 30wt%. Two experimental tests have been carried out in order to determine the mechanical properties, such as tensile and Brinell hardness tests. In the case of tensile and Brinell hardness tests, the characterization was performed on two types of composite plates reinforced with Woven Carbon Fiber and Hybrid Woven Kevlar and E-Glass with Epoxy (WCF-HWKG/EPOXY) and Hybrid Woven Kevlar and E-Glass with Epoxy (HWKG/EPOXY). Consequently, it has been observed that the tensile and hardness properties of the hybrid composite material (HWKG/EPOXY) are respectively 36% and 46.43% lower compared to (WCF-HWKG/EPOXY). Based on these findings, the studied materials demonstrate potential applications across various fields, including aeronautics, aerospace, and high-performance automotive sectors.

Study on the Alkali–Sulfur Co-Activation and Mechanical Properties of Low-Carbon Cementitious Composite Materials Based on Electrolytic Manganese Residue, Carbide Slag, and Granulated Blast-Furnace Slag

Study on the Alkali–Sulfur Co-Activation and Mechanical Properties of Low-Carbon Cementitious Composite Materials Based on Electrolytic Manganese Residue, Carbide Slag, and Granulated Blast-Furnace Slag

Synthesis and sorption properties of hybrid composite materials based on saponite and copolymer 5-(4′-nitro)-phenylazo-8-methacryloxyquinoline: MMA

A new polymer–mineral composite was synthesized by adsorption of the copolymer of 5-(4′-nitro)-phenylazo-8-methacryloxyquinoline with methyl methacrylate on the surface of natural saponite clay. Using computer processing of isotherms of low-temperature adsorption–desorption of nitrogen, a decrease in the specific surface area of saponite after fixing this copolymer was recorded. Using the BJH method, it was calculated that after the adsorption of the copolymer, the average pore volume of the surface of the original mineral decreases and the average pore diameter increases. The sorption capacity of the synthesized composite concerning metal ions compared to the original mineral increases.

Evaluating the Impact of Environmental and Operational Conditions on the Characteristics of CFRP Epoxy Composites

The purpose of this study is to determine the material properties of CFRP composites in the form of a fabric for the construction of racing car bodywork. This work focused on the determination of the strength and tribological properties as well as investigating the effects of the operating environment on the developed material. Three material variants, differing in the number of layers used to produce the reinforcement, were used in this study. The tests were carried out on two-/three-/four-layer sheets produced by infusion. Due to the later use of the tested composites for the sheathing of a racing car, the results obtained were analysed in terms of the most favourable strength properties while keeping the weight as low as possible. In this study, the hardness, impact strength, and tensile and bending stresses of the developed composites were examined. In addition to the strength properties, the density, the effects of immersion in water, and the composite’s resistance to staining and friction in the presence of aggressive media were also checked. The structure and the breakthroughs resulting from the strength tests were observed using a stereoscopic microscope. The material’s resistance to sunlight and UVB was also tested.

Preparation and Hydration Properties of Sodium Silicate-Activated Municipal Solid Waste Incineration Bottom Ash Composite Ground-Granulated Blast Furnace Slag Cementitious Materials.

The production of municipal solid waste incineration bottom ash (MSWIBA) is substantial and has the potential to replace cement, despite challenges such as complex composition, uneven particle size distribution, and low reactivity. This paper employs sodium silicate activation of MSWIBA composite Ground-granulated Blast Furnace slag (GGBS) to improve the reactivity in preparing composite cementitious materials. It explores the hydration performance of the composite cementitious materials using isothermal calorimetric analysis, Fourier-transform infrared (FTIR) spectroscopy, XRD physical diffraction analysis, and SEM tests. SEM tests were used to explore the hydration properties of the composite gelling. The results show that with an increase in MSWIBA doping, the porosity between the materials increased, the degree of hydration decreased, and the compressive strength decreased. When the sodium silicate concentration increased from 25% to 35%, excessive alkaline material occurred, impacting the alkaline effect. This inhibited particle hydration, leading to a decrease in the degree of hydration and, consequently, the compressive strength. The exothermic process of hydration can be divided into five main stages; quartz and calcite did not fully participate in the hydration reaction, while aluminum did. The vibrational peaks of Si-O-Ti (T = Si and Al) were present in the material. The vibrational peaks of XRD, FTIR, and SEM all indicate the presence of alumosilicate network structures in the hydration products, mainly N-A-S-H and C-A-S-H gels.

Self-healing property of a gel-elastomer two-phase composite material

While self-healing silicones are required for many practical applications, conventional methods of incorporating self-healability in silicones involve generation of bond-forming moieties within the backbone of the oligomer itself. Such processes involve multiple synthesis steps that turn the silicone expensive and less amenable for scale-up. In contrast, hydrogels can be made self-healing by different simple yet robust chemical routes. Hydrogels however lack mechanical strength, necessary for most engineering applications. To meet the above need, we have introduced here a novel two-phase material, consisting of self-healing hydrogel droplets embedded as microscopic healers inside the continuous matrix of silicone. The hydrogel phase, consisting of starch and polyvinyl alcohol (PVA) as the oligomers and multivariate borate ion as the crosslinker is dispersed in silicone oligomer mixed with the curing agent and both phases are allowed to crosslink. Controlled fracture tests on the resultant crosslinked material show that two cut surfaces of it get joined instantaneously with the tensile failure stress reaching as high as 35 kPa; this material remains healable also over ten cycles of incision and reattachment. The hydrogel can act also as an external glue to heal two incised surfaces of the two-phase composite to achieve durable fracture strength and thereby help forming different polygonal structures with angled joints. We have demonstrated also bio-compatibility of the two-phase material thereby opening up its possible use in large variety of biomedical applications.

Investigation on the torsional property of hybrid composite/metal shafts at different service temperatures: Experimental and analytical study

AbstractTorsional tests were conducted to investigate the influence of service temperature on torsional property of composite/steel hybrid structures. In the experiment, two types of lightweight hybrid composite‐metal shafts were tested at both room temperature and various elevated temperatures up to 150°C, including hybrid shafts with and without a metal core. Consequently, the torsional stiffness of the two hybrid shafts at different temperatures was calculated based on the recorded angular deformation‐torque curves. The experimental results revealed a significant decrease in the torsional stiffness of the hybrid shaft without metal core as the increase of service temperature, while the torsional stiffness of the one with metal core remained almost unchanged, especially at high temperatures. In addition, a finite element model was proposed to predict the torsional behavior of the hybrid shafts at different service temperatures. In the model, an empirical equation was introduced, and micromechanical method was adopted to determine the temperature‐dependant elastic properties of composite material and adhesive layer in the hybrid structure. Then, the predicted torsional property was compared to the experimental results for model verification.Highlights Two types of hybrid composite‐metal shafts are designed and manufactured. Torsional tests are conducted at both room and elevated temperatures up to 150°C. A finite element model applicable to shaft at various temperatures is proposed. The temperature‐dependant property is characterized by an efficient equation.

Study on Bonding Behavior between High Toughness Resin Concrete with Steel Wire Mesh and Concrete

This paper investigates the interfacial bonding behavior between high toughness resin concrete with steel wire mesh (HTRCS) and concrete. A total of five sets of fifteen double shear specimens were tested for parameters including concrete strength and material properties of HTRCS composites. The test results showed that the failure mode of DS1 specimens was partial debonding and fracture, and the rest of the specimens were the fracture of HTRCS. The concrete strength and reinforcement ratios of HTRCS composites were positively correlated with interfacial adhesion properties. When the concrete strength was increased from C30 to C40 and C50, the ultimate load increased by 43.4% and 43.2%, respectively. The ultimate load capacity increased by 32.1%, with the reinforcement ratio of HTRCS composites increasing from 1.05% to 1.83%. Moreover, the bonding slip model and the bearing capacity formula for the interface between HTRCS composites and concrete were proposed, and the calculation values were in good agreement with the test values, with an average value of 0.978.

Photocatalytic activity of polyaniline‐potassium doped nickel oxide nanocomposites: A comprehensive investigation on multifaceted properties

AbstractPolyaniline‐potassium doped nickel oxide nanocomposites (PANI/KNO) were efficiently synthesized via an in situ chemical oxidation method, meticulously confirmed by comprehensive x‐ray diffraction, Fourier transformation infrared spectroscopy, energy dispersive x‐ray spectroscopy, selected area electron diffraction, and x‐ray photoelectron spectroscopy analyses. The crystallite size and strain exhibited distinct behaviors, while field emission scanning electron microscopy revealed a blend of irregular spherical shapes and nanofibers, further confirmed by high resolution transmission electron microscopy. These composites exhibited significantly enhanced thermal stability, surpassing PANI by 1.39 times, and showcased a band gap exceeding 3 eV, along with multiple photoluminescence peaks at room temperature (RT). Moreover, their RT AC conductivity experienced a remarkable surge by 4.91 times compared to pure polyaniline. Jonscher's Power Law model and the Havriliak–Negami relaxation model are employed to elucidate the electrical properties of composite materials. The composites displayed nonDebye relaxation behavior with increased conductivity, as observed through impedance analysis, electrical modulus evaluation, and dielectric constant assessment. Additionally, evident superparamagnetic properties and multiple magnetic domains further contributed to their effectiveness. The PANI/KNO composite demonstrated photocatalytic efficiency, achieving over 90% degradation of methylene blue dye across four cycles, thus highlighting its superior photostability. Furthermore, investigations into its response to pH variations and scavenger activity underscored its immense potential for highly effective photocatalytic applications.

4D printing of fiber-reinforced auxetic structures: the building blocks: A review

Abstract Four-dimensional (4D) printing has recently received much attention in the field of smart materials. It concerns using additive manufacturing to obtain geometries that can change shape under the effect of different stimuli. Such a technique enables the fabrication of 3D printed parts with the additional functionality of scalable, programmable, and controllable part shapes over time. &amp;#xD;This review provides a comprehensive examination of advances in the field of 4D printing, emphasizing the integration of fiber reinforcement and auxetic structures as crucial building blocks. &amp;#xD;The incorporation of fibers enhances structural integrity, while auxetic design principles contribute unique mechanical properties, such as negative Poisson's ratio and great potential for energy absorption due to their specific deformation mechanisms. Therefore, they present potential applications in aerospace, drones, and robotics.&amp;#xD;The objective of this review article is first to describe the distinctive properties of shape memory polymers (SMPs), auxetic structures, and composite (fiber-reinforced) materials. A review of applications that use combinations of such materials is also presented when appropriate. The goal is to get a grip on the delicate balance between the different properties achievable in each case. The paper concludes by describing recent advances in 4D printing of fiber-reinforced auxetic structures.&amp;#xD;

Effects of modified coal gasification fine slag on the processing and mechanical properties of natural rubber composites

AbstractCoal gasification fine slag (CGFS) is rich in unburned residual carbon, silica and alumina, and has a large specific surface area, making it a potential polymer‐reinforcing filler. Tea polyphenol (TP)‐modified coal gasification fine slag (TP‐CGFS‐T) was prepared using flotation and modification methods in this study. The effects of unmodified and modified CGFS‐T on the sulfurization performance, processing properties, thermal stability, fracture morphology, and mechanical properties of natural rubber composite materials were investigated. Results indicated that after TP modification, CGFS‐T exhibited highly uniform dispersion on the surface without the agglomeration of fillers. When the dosage of TP‐CGFS‐T was 20 phr, the comprehensive performance of the natural rubber (NR) composite material was optimal, with a tensile strength of 12.12 MPa, the elongation at break of 1208.83%, the tear strength of 30.94 kN/m, and the shore hardness of 38.7 A. As the amount of TP‐CGFS‐T increased, the scorch time of NR increased, which enhanced the processing safety of rubber. This study provides a strategy for treating CGFS, which can both reduce the pollution caused by CGFS and save costs for NR composite materials.Highlight The CGFS is separated into concentrate and tailings by flotation. The compatibility between fillers and the matrix is enhanced by TP modification of CGFS‐T. The composite materials show excellent mechanical and processing properties.

Effect of three-dimensional to one-dimensional orientation of cellulose nanofiber sizing agents on carbon fibers under magnetic and electric fields on composite material properties

Nanoparticle-containing sizing agents are essential for the overall performance of high-quality carbon fiber (CF) composites. However, the uneven dispersion of nanoparticles often leads to agglomeration on the surface of CF after sizing, consequently diminishing the material properties. In this study, the properties of cellulose nanofibers (CNFs) that can respond to magnetic and electric fields were utilized to achieve three-dimensional to one-dimensional orientations in CFs containing sizing agents. Cobalt ferrite (CoFe2O4) was utilized to enhance the response of CNFs to a magnetic field, and subsequently, it was combined with an electric field to attain a higher degree of orientation. The occurrence of nanoparticle agglomeration is diminished on CF surface, while establishing a structured network. The flexural strength and thermal conductivity of CF composites treated with CoFe2O4 self-assembled CNF sizing agent exhibit an increase of 54.23 % and 57.5 %, respectively, compared to those of desized CF composites, when subjected to magnetic and electric fields. Consequently, the approach can depolymerize the nano-fillers within the sizing agent and orient it into the carbon fiber under the influence of magnetic and electric fields, effectively improving the mechanical properties and thermal conductivity of the composite material.

Comparative experimental study on photothermal conversion and shape memory properties of MF-based flexible composite phase change materials loaded with carbon nanotubes and polydopamine

Efficient use of solar energy can effectively alleviate the problem of energy shortages. Currently, extensive researches have been carried out on photothermal conversion materials. However, factors such as photothermal conversion and thermal conductivity limit the practical implementation of photothermal materials. In this research, a novel flexible composite phase change material (CPCM) with melamine foam (MF) as the supporting skeleton, carbon nanotube (MWCNT)/polydopamine (PDA) as the light-absorbing coating and polyethylene glycol (PEG) as the energy storage material was successfully prepared. The results show that the MF-based CPCMs have good shape stability with a leakage of only 0.9 %, and high phase change enthalpies, the melting enthalpy was above 172.0 J/g. In addition, the thermal conductivity was improved due to the introduction of light-absorbing coatings into the CPCMs. Compared with MF/PEG, MWCNT/MF/PEG, and PDA/MF/PEG, MWCNT/PDA/MF/PEG were improved by 35.21 %, 8.6 % and 29.46 %, respectively. Finally, the average charging efficiency of MWCNT/PDA/MF/PEG is 96.26 %, which is 62.33 % and 20.1 % higher than that of MWCNT/MF/PEG and PDA/MF/PEG respectively, indicating that MWCNT and PDA nanofillers played a synergistic role in enhancing the performance of CPCMs. This study provides new and innovative ways for the design of photothermal materials.

Determination of selective laser melting process parameters of tungsten carbide powders coated with nickel via electroless plating for improved interface properties

Tungsten carbide powders are commonly used at various industrial applications due to their high hardness. However, these powders may exhibit low binding and processing challenges without a binder. Therefore, various binding methods such as electroless Ni coating are used to hold WC powders together, increase their processability and improve the mechanical properties of the final product. Electroless Ni plating plays an important role in the use of WC powders, especially in processes such as selective laser melting. The structural, tribological, and mechanical properties of parts manufactured by SLM method are significantly influenced by the parameters employed in the process. Hence, optimizing process variables is essential to unlock the full potential of this advanced manufacturing technique. The main objective of this study was to identify the optimum process parameters for the SLM method of WC-Ni composite powders, which were prepared by coating WC powder materials with electroless Ni. Experimental investigations focused on analyzing the laser power, scanning speed, and hatch spacing parameters. The effects of these parameters on the mechanical and tribological properties of WC-Ni composite material were investigated using microhardness tester, tribometer device, optical microscope, 3D optical profilometer and scanning electron microscope. Eventually, it was determined that the manufacturing parameters employed in the SLM method had a significant impact on relative density, microstructure, surface roughness, hardness, and tribological properties. Samples exhibited a relative density of nearly 99%, and the highest observed hardness value was 1962 HV. This article supports a specialized SLM manufacturing process developed specifically to enhance durability and performance across a broad spectrum of industrial applications through interface improvement and the optimization of manufacturing parameters.

Research on the synergistic flame retardation of epoxy resin through surface-modified aluminum diethylphosphinate in conjunction with DOPO and CFA

Surface modification of aluminum diethylphosphinate (ADP) was successfully achieved through the utilization of silane coupling agent KH-560. Simultaneously, the modified aluminum diethylphosphinate (K-ADP) served as the primary flame retardant, with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as the phosphorus-based flame retardant and melamine cyanurate (CFA) as the nitrogen-based synergistic flame retardant. This approach was employed to investigate the flame-retardant modification of epoxy resin. The optimal dosage of the surface modifier was investigated through moisture absorption test and viscosity measurements. Synergistic flame-retardant interactions among K-ADP, DOPO, and CFA were examined using techniques such as cone calorimetry test, thermogravimetric analysis, and residual char infrared analysis. The results indicated that the optimal dosage of KH-560 is 5%, resulting in a significant reduction in moisture absorption to 0.195%. At 80 °C, the addition of K-ADP leaded to only a 22.7% increase in system viscosity, demonstrating a notable viscosity reduction effect. When the addition of K-ADP is 14%, the Limiting Oxygen Index (LOI) value reached 30.5%, achieving a V-0 rating. Moreover, by maintaining the total addition at 14% and introducing DOPO and CFA, it is evident that most of samples meet UL-94 V-0 rating, with the LOI elevated to 32.2%. CCT results indicated a significant decrease in both average heat release rate and total smoke production, reduced by 24.1% and 7.0%, respectively. This notably enhanced the flame-retardant and smoke-suppressant properties of the EP composite material. The addition of K-ADP, DOPO, and CFA improved the mechanical performance of the EP composite material, surpassing the effectiveness of adding ADP individually.

Study on the performance of porous polyimide bearing cage material modified with molybdenum disulfide and glass fiber

This study explores material modification utilizing molybdenum disulfide and glass fiber as lubricating and reinforcing modified materials respectively. The specimens underwent tests for mechanical-physical properties, oil storage capacity and frictional characteristics. The differential analysis identified the optimal mechanical-physical properties of the porous composite PI material at a molding pressure of 192 MPa, molding temperature of 330°C, 9% of AC foaming agent content, 8% of molybdenum disulfide content, and 20% of glass fiber content. The wear coefficient increased with load and decreased with rotational speed, indicating the suitability of this porous composite oil-retaining PI material for medium-high-speed and low-load frictional conditions.

Enhancing the photocatalytic and antimicrobial activity of ZnFe2O4 by composite with Ag2WO4 semiconducting material

In this research article, we have performed the degradation of methylene blue dye (MB) in the presence of ZnFe2O4/Ag2WO4 photocatalyst. These catalyst materials are prepared by a simple combustion method followed by a solution mixing method. The structure and morphology of prepared composite material are analyzed by using XRD, FTIR, UV-DRS, and scanning electron microscopy. The antimicrobial property of composite material is studied against E. coli and S. aureus food pathogenic bacteria. After the incubation time, the antimicrobial activity of the composite material shows a clear zone of inhibition This composite photocatalyst is a promising material to increase the degradation percentage of MB (Methylene blue) dye in the presence of UV light. ZnFe2O4/Ag2WO4 composite material shows 72.72% degradation of the MB dye. The photocatalytic activity of composite material has been performed by varying the catalyst dosage and pH level of the medium used for the degradation process. The role of composite material in the degradation of dye and their increase in the reaction rate has also been discussed. From these results, the ZnFe2O4/Ag2WO4 composite is a good material to degrade the toxic pollutants in the environment.

Evaluation of Composite Structural Materials for Heliostat Cost Reduction

Abstract Structures manufactured from steel comprise up to 40% of a CSP heliostat's cost. Composite struc-tures represent a potential opportunity to reduce this cost. A reference heliostat structural model has been created with a reflector area of 25m2. The design, constructed of low-carbon steel, pro-vides baseline deflection and stiffness under a 21 m/s operating wind speeds. Wind loads on the tracker structure are determined for both operating and stow conditions. An established roster of suitable metal alternative materials is considered including: glass, basalt, and carbon reinforced polymer (GFRP, BFRP, and CFRP respectively). Three heliostat components are investigated: the pylon, torque tube, and the purlin-strut assembly. Composite material properties are substituted for those of steel, and the beams are re-sized to match the original steel components' deflection under given wind loads. Weight and cost changes resulting from this resizing are evaluated. It is found that GFRP and BFRP represent a 3X–6X cost premium for the same operating deflection character-istics as steel across all three investigated component classes; with weight reduction only achieved for the purlin-strut assembly. While CFRP components can achieve approximately 25–75% weight savings depending on the application, this comes with a 9X–14X cost increase over the steel base-line for tube-type structures and roughly 5X cost increase when replacing c-channel structures. This work does not rule out the possibility of cost savings when the heliostat design and kinematics to take advantage of composites' specific properties.