Mechanical Properties Of Composites Research Articles

Improving mechanical properties of huntite hydromagnesite reinforced flame retardant polymer composites with calcite and zeolite minerals

AbstractAlthough inorganic minerals used as flame retardants in firefighting are much safer alternative to halogen‐containing ones, it is seen that while they impart non‐flammability, they impair some mechanical properties of polymer composites. In this study, calcite and zeolite minerals, with well‐known incombustibility properties, were used together with huntite hydromagnesite as auxiliary minerals to obtain better mechanical properties. In this context, a synergistic effect was created by adding zeolite and calcite to polymer composite systems containing huntite hydromagnesite, and flame retardant polypropylene matrix composites were produced using a twin screw extruder. The thermal properties of the produced composites were determined by thermogravimetric analysis (TGA). Tensile test was applied to the samples to determine their mechanical properties. Structural and morphological properties were characterized by scanning electron microscopy (SEM) analysis. It was found that with an additive load of 60% by weight, the modulus of elasticity of pure polypropylene was increased from 1215 to 3362 MPa. In addition, by loading zeolite together with huntite hydromagnesite, the maximum tensile strength increased from 15.6 MPa to 22.9 MPa, resulting in an increase of 46.80%. Consequently, the synergistic effect obtained by using zeolite with huntite hydromagnesite improved the mechanical properties of the composite.

Mechanical properties for composites with dammar resin reinforced with crushed corn cob

The study focused on the potential use of agricultural waste (corn cob) in the manufacturing of composite materials. In the first stage, composite materials were manufactured and tested using synthetic matrices (epoxy and acrylic) and hybrid matrices based on dammar resin (50% dammar, 60% dammar, and 70% dammar). Since it was observed that the samples had low mechanical properties under tensile and bending loads, the study was expanded to the production of sandwich-type composites with silk fabric facings. It was found that, by utilizing silk fiber, both tensile and bending strength increased from a few hundred percent up to a few thousand percent, compared to the samples that are only reinforced with crushed corn cob.

Evaluation of mechanical and morphological properties composite of Agel Leaf Fiber (ALF)-epoxy modified with carbon powder

This research focuses on the successful development of Agel Leaf Fiber (ALF)-Epoxy composites added with Carbon Active Powder (CAP) and printed using the Vacuum Pressure Infusion (VAPRI) method. Considering the importance of determining the mechanical properties of composites as raw materials for making fishing boats, this research aims to determine the use of Agel Leaf Fiber (ALF) in polymer matrix composites. The composite morphology was analyzed using Scanning Electron Microscopy (SEM) and ImageJ software. The mechanical properties evaluated included Tensile Strength, Flexural Strength, and Hardness. The composite was prepared by incorporating CAP in varying volumes of 0 %, 10 %, and 30 % with a fixed ALF percentage of 40 %. The results showed that the addition of CAP significantly increased the tensile strength to 128.51 MPa, with 0.068 % elongation, 1787.39 MPa modulus of elasticity, and a hardness value of 75.2 HD. Furthermore, the addition of 10 % carbon exhibited a remarkable improvement in flexural strength, reaching 238.51 MPa. This improvement could be attributed to reduced porosity, resulting in enhanced bonding between ALF-CAP-Epoxy components. The flexural strength of the composite with the highest CAP content experienced a significant increase of 238.51 MPa. Thus, Agel leaf fiber has the potential to be used as a reinforcing material in the manufacture of composites and is applied in the manufacture of environmentally friendly fishing boat bodies

Influence of CNTs on the gradient phase structure formed by the layered resin structure used to model the interlaminar region of interleaved FRPs

Abstract The interleaved fiber-reinforced polymer composites (FRPs) by carbon nanotubes (CNTs)/thermoplastic polyetherketone-cardo (PEK-C) hybrid interleaves show the potential of comprehensively improving the mechanical properties of composites and have been hotspot. However, the synergistic effect and mechanism of CNTs and TP resin have not been attained. The interlaminar region of interleaved composites is too narrow and complex to be fully analyzed. Therefore, the layered resin structure composed of an interlayer and a matrix (epoxy) layer was prepared to model the interlaminar region in this study. The evolution of gradient structure developed by the layered structure in curing and the influence of presence of CNTs in interlayer were investigated based on morphology characterization. The results showed that epoxy resin gradually diffused into the interlayer, resulting in the concentration gradient and the resultant gradient phase structure. The presence of CNTs in hybrid interlayer hindered the resin diffusion and consequently hindered the formation of dual-phase structure, which was not conducive to the toughness improvement. The inappropriate high temperature was not recommended due to the effect of facilitating diffusion, probably resulting in the formation of excrescent epoxy layer in the interlaminar region and undesired mechanical performance. This study conducted experiments on resin system to simplify the interesting subject and the results will help to develop the synergistic mechanism of TP resin and nanoparticles.

Water Absorption Rate of Kenaf Fiber (KF)/ Hydroxiteapatite (HA) in Simulated Sea Water

Hydroxiteapatie (HA) as a filler is a mixture that is often added to alloy or composite products. This study investigates the development of polyester composites reinforced with kenaf fiber (KF) and hydroxiteapatite (HA) fillers in order to reduce their environmental impact. The strength, decomposability, and low weight of these composites make them ideal for a wide range of applications due to their exceptional mechanical properties. In addition to tensile and bending tests, water absorption tests, and immersion in seawater simulations, the composites were evaluated under demanding conditions. The water absorption rate increased with increasing fiber volume percentages in the composite, primarily due to the water-absorbing properties of the KF and HA particles. In contrast, the KF-15%HA-reinforced composite, which underwent soaking at 50 °C, exhibited the lowest tensile strength of the three composites. Additionally, the temperature at which aging occurs influences the composite's ability to absorb water and its mechanical properties. A filler may improve the mechanical properties of composites made from kenaf fibers, and it can also affect moisture absorption, reducing moisture absorption and increasing adhesion.

Pengaruh Penambahan Serat Kulit Jagung Terhadap Sifat Mekanik Komposit Polipropilena (PP) dengan Penambahan Aluminium Oksida (Al2O3) dan Maleat Anhidrida (MAH) sebagai Coupling Agent

The utilization of polymer composites in the automotive field is expanding due to their characteristics such as strength, stiffness, and light weight. Polypropylene (PP) is one of the thermoplastic polymers widely used in composite manufacturing due to its lightweight, corrosion-resistant, and recyclable properties. However, to improve its mechanical properties, modifications using natural reinforcements and coupling agents continue to be made. Corn husk fiber is a natural resource that has potential as a natural reinforcement in polymer composites, it has the advantages of good tensile strength, light weight, and is biodegradable. The addition of Aluminium Oxide (Al2O3) and Maleic Anhydride (MAH) as coupling agent can improve the adhesion between fiber and polymer matrix, support more even load distribution, and optimize the mechanical properties of the composite Al2O3 and MAH on the mechanical properties of PP composites. The composition used was polypropylene: corn husk fiber rasio :Al2O3: MAH, namely 90:5:5:0, 89:5:5:1, 87:5:5:3, and 85:5:5:5% by weight. Tensile strength test using Universal Testing Machine (UTM) and crystallinity test using Differential Scanning Calorimetry (DSC) were conducted to evaluate the material performance. The highest value of tensile strength and crystallinity in the composition with 0 %weight MAH. The results of these tests, showing that the greater the composition of corn husk fiber has an influence on the decrease in tensile strength and crystallinity of the composite.

Lignin-xylan nanospheres prepared by green and quick method from lignocellulose and used as additive in PVA films

Lignin, as an amorphous three-dimensional aromatic polymer, was able to self-assemble into lignin nanoparticles (LNPs) to realize valorization of lignin. Here, lignin-xylan extractives were extracted from grape seed (GS) and poplar by acidic THF at room temperature, and effectively produced lignin-xylan nanospheres via spin evaporation. The morphology and chemical properties of nanospheres were determined by its natural origins, consequently influencing its application. For the lignin-xylan extractive from grape seed, the lignin was composed of guaiacyl (G) and p-hydroxylphenyl (H) units and the hollowed nanospheres (GS-LNPs) with 362.72 nm diameter was produced. The extractive from poplar was composed of G-syringyl (S) typed lignin (80.30 %) and xylan (12.33 %), that can assemble into LNPs with smaller size (229.87 nm), better PDI (0.1), and light color. The hybrid particles showed the qualities of lignin and xylan, that properties led to the LNPs@PVA composite films with UV-blocking capability, strong mechanical strength and hydrophobicity, and transparency ability of visible light. P-LNPs showed better performance as the film additives, due to its lower particles size and high content of unconjugated -OH from xylan. Xylan was significant in the composite films, and lowering the xylan content resulted in the decrease of the composite film's mechanical properties and hydrophobicity.

Electron beam radiation constructed and improved bone repairing performance based on hierarchical thermoplastic polyurethane/graphene oxide/hydroxyapatite hot melt adhesive with high flow ductility

AbstractThe aging population increased the demand for the development and utilization of bone filling materials. In this study, hydroxyapatite (HAP) and graphene oxide (GO) were introduced into thermoplastic polyurethane (TPU) by melt mixing and electron beam radiation to obtain the new hot melt adhesive (TPU/HAP/GO). The structures and morphologies of the TPU/HAP/GO were analyzed using FTIR, XRD, SEM, BET, DSC. The mechanical properties of the TPU/HAP/GO were evaluated using a universal testing machine. TPU/HAP/GO was demonstrated to have good bacterial inhibition by the zone of inhibition test and plate method. The good biocompatibility of the hot melt adhesive was demonstrated using the MTT method and the Hoechst 33342/PI double staining method. The osteogenic differentiation of mouse osteoblasts (MC3T3‐E1) treated with TPU/HAP/GO was detected by alkaline phosphatase (ALP) staining. ALP staining showed that the hot melt adhesive promoted the differentiation of MC3T3‐E1 cells into osteoblasts. This hot melt adhesive had great application potential in bone tissue engineering.Highlights Green electron beam radiation method for synthesizing hot melt adhesives. Enhanced mechanical properties of composites by incorporation of graphene oxide. Improvement of antimicrobial and osteogenic capacities for polyurethane.

Enhanced mechanical properties of epoxy composites using cellulose micro‐ and nano‐crystals

AbstractEpoxy polymers are commonly utilized in structural applications due to their high bearing capacity and excellent chemical resistance. However, their inherent brittleness poses a significant challenge for their use in high shock and fracture strength products. To address this shortcoming, fillers can be incorporated into the polymer during preparation. In this study, we aimed to investigate the effect of incorporating cellulose‐based fillers, namely cellulose nanocrystals (CNCs) and microcrystalline cellulose (MCC), on the mechanical properties of epoxy polymer composites. The study evaluated the impact of various factors, including filler concentration, particle size, and moisture content, on the mechanical properties of the composites. The results demonstrated that the incorporation of CNC or MCC powders at concentrations below 5% could enhance the mechanical properties of the resulting epoxy composites without adversely affecting their surface and thermal properties. The maximum tensile strength and fracture toughness of the filler‐based epoxy composites were achieved at 2 and 4 wt% for CNCs and MCC, respectively. CNCs with a smaller particle size distribution were found to be much more effective than MCC in improving the mechanical properties of the epoxy composites. Furthermore, utilizing dried fillers resulted in a higher improvement in tensile strength, which was achieved at lower filler concentrations.

Corrosion behavior of precracked SiCf/SiC composites under 1200–1300°C Na2SO4‐wet‐oxygen environment

AbstractSiCf/SiC composites, as promising materials for the hot‐section components of turbine engines, are susceptible to hot corrosion due to the steam environments. Especially, under rotational and thermal stress, numerous microcracks may be generated in the SiCf/SiC ceramic matrix, which can trigger the rapid invasion of corrosive gases and deteriorate the composite mechanical properties. Therefore, it is of great importance to investigate the degradation mechanisms of SiCf/SiC with precracks existing. Here, the corrosion behavior of precracked SiCf/SiC in the Na2SO4‐wet‐oxygen environment was evaluated. By comparing mechanical evolution under different corrosion conditions, microfailure mechanisms of SiCf/SiC were revealed. The results indicate that brittle cracking of the matrix and oxidation erosion of fibers are the key factors in reducing the tensile strain of composites. Specifically, the composite damage resistance increases at 67 MPa‐1300°C. At this point, the prestress level is moderate and close to the matrix cracking limit. The prefabricated microcracks can be healed at 1300°C by liquid oxidation products, which hinders cracks bridging large‐scale. This study is conducive to a better understanding of failure mechanisms of SiCf/SiC in complex service environments.

A coupled ductile damage model for metal matrix composites: Development and application

The prediction of failure behavior in metal matrix composites remains a significant challenge in both composition design and process optimization. An accurate prediction of metal matrix composites damage evolution is a crucial for enhancing the quality of metal matrix composites forming. As the material undergoes plastic deformation, it experiences void initiation and growth, resulting in consequential microstructural transformations, stiffness degradation, and mechanical property shifts. In this work, we employed a model to predict damage progression and stiffness decay in metal matrix composites. Leveraging the Gurson-Tvergaard-Needleman framework, this homogenization model accounts for the impact of the evolution of voids and reinforcing phases, on the composite's mechanical properties. The influences of reinforcing phases on voids nucleation and growth were particularly considered, and also the interaction of voids, matrix, reinforcing phases, and stiffness were integrated to discuss their impacts on damage evolution and mechanical performances of the metal matrix composites. The model was implemented as an Abaqus VUMAT subroutine, with its validity gauged by analyzing the influence of model parameters on failure mechanisms and inherent elastoplastic traits. Utilizing the flanging process of carbon nanotube-reinforced aluminum matrix composites as a case study, a significant agreement was observed between experimental and simulated force-displacement profiles, as well as crack evolution routes.

Improving wear performance, physical, and mechanical properties of iron sand/epoxy composite modified with carbon powder

This study was conducted to investigate the usage of iron sand as composite reinforcement. The addition of carbon powder with variations of 15 wt%, 20 wt%, and 30 wt% is expected to enhance the interfacial bond between iron sand and epoxy matrix to be better. Physical and mechanical properties of the composite were investigated using a wear resistance test Pin on Disc method, shore-D hardness, bending test, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The results showed an increase in wear resistance and mechanical properties of composite due to the addition of carbon powder. This was confirmed by the fact that the HCP composite with 30 wt% carbon powder showed a good increase in wear resistance but a reduction in flexural properties and hardness values. Meanwhile, the LCP composite with 20 wt% carbon powder was recommended in terms of good flexural properties. The increased mechanical properties of composite were supported by composite crystallinity index value recorded to be 59.45 % from the XRD test. SEM analysis showed better dispersion and interfacial bonding for carbon powder and iron sand in the composite matrix. These results are expected to contribute to the new development of composite brake pad.

A strong, machinable, and multifunctional Ti3SiC2-(Ti3SiC2-Cf) composite: Gradient architecture and mechanical properties

Ti3SiC2, as one of the most typical MAX ceramics, has been extensively studied as a potential high-temperature structural material. However, the restrictive relations between strength and toughness of Ti3SiC2 and Ti3SiC2-based materials have hampered their industrial applications. Herein, we reported the successful fabrication of Ti3SiC2–(Ti3SiC2–Cf) functionally graded materials (FGM) via hot-press sintering Ti3SiC2 and short Cf-derived preceramic papers. The microstructure evolution as well as the effect of sintering temperature on phase composition and interfacial reaction were investigated. Flexural strength and fracture toughness from ambient temperature to 1000 °C of the graded composites were determined to evaluate the mechanical performance. The results have shown that chemical reactions occurred between carbon fibers and Ti3SiC2 matrix, which leads to the formation of SiC interfaces with strong covalent bonds. The newly developed Ti3SiC2–(Ti3SiC2–Cf) graded composite materials exhibited excellent comprehensive performance as compared to that of monolithic Ti3SiC2. The flexural strength and fracture toughness of the graded composite at room temperature can be reached to 526 MPa and 7.46 MPa m1/2, respectively. However, there is no significant change in flexural strength and fracture toughness from RT to 1000 °C. The fracture micrographs also reveal that fiber breaking、pulling out and debonding are the primary mechanisms that contribute to the superior mechanical properties of composites. The exceptional performance demonstrated in Ti3SiC2–(Ti3SiC2–Cf) graded materials also makes them attractive choices for a variety of heatproof devices in aerospace sectors.

Fabrication, microstructure and multi-scale mechanical properties of 2.5D oxide fiber reinforced oxide composites

2.5D oxide/oxide composites have attracted substantial attention due to their good integrity. In this work, a simple process was used to manufacture the 2.5D aluminosilicate fiber reinforced alumina (2.5D-ASf/Al2O3) composites. The influence of 2.5D preform on the microstructure of the 2.5D-ASf/Al2O3 composite was studied in-depth mainly by X-ray computed tomography. Also, the change mechanism of the micro- and macro- mechanical properties of composites, especially the anisotropic mechanical properties were further analyzed. The results showed that the matrix modulus and fiber strength had great effects on the mechanical properties of the 2.5D-ASf/Al2O3 composites with different densification cycles. And the microstructure characteristics of the 2.5D-ASf/Al2O3 composites were consistent with those of the 2.5D preform, such as the warp direction cross-sections invariably had higher porosity of the pores>10 μm and larger pores than the weft direction cross-sections. This was also one of the key factors affecting the anisotropic mechanical behavior of the 2.5D-ASf/Al2O3 composites.

Effect of Ti and Zr on high temperature mechanical and thermal properties of MoCu composites

Based on the design concept of diversified alloys, the reinforcement of TZM alloys was combined in the fabrication of MoCu composites. The MoCu composites were prepared by vacuum hot press sintering under the effect of Ti, Zr elements added separately or simultaneously, and the microstructure adjustment was realized by mechanical ball milling on the pretreatment of the original alloy powder. The results show that Ti and Zr elements form metal-based solid solutions and intermetallic compounds by diffusion with Mo and Cu matrix during the sintering process. It can not only reduce the sintering activation energy of MoCu composites to improve the densification, but also improve the mechanical properties of the composites through certain solid solution strengthening and second phase strengthening. When Ti, Zr elements are added at the same time, Zr elements can enhance the β-stabilizing effect of Mo on Ti elements and improve the solid solution effect between Ti and Mo, Cu matrix, which further improves the interfacial bonding. Therefore, the 60Mo35Cu2.5Ti2.5Zr composites have the best overall performance, and their thermal properties and mechanical properties at room and high temperatures are greatly improved compared with the original 60Mo40Cu composites.

Effect of Kigelia pinnata biochar inclusion on mechanical and thermal properties of curtain climber fiber reinforced epoxide biocomposites

AbstractThis article explored the influence of curtain climber fiber and Biochar derived from Kigelia pinnata fruit fiber on a polyepoxide‐based composite material's thermal, mechanical, dielectric, and mechanical properties. Before commencing the composite production process, the surface of the curtain climber fiber underwent treatment with a solution consisting of 5% silane to enhance the bonding between the fiber and the matrix. The hand layup method and compression molding were used to produce the composite panels and tested according to the appropriate standards set by the ASTM. According to these findings, the mechanical properties of the composites were enhanced by adding 30% curtain climber fiber and 5% biochar. The load distribution on the fiber was consistent throughout. The composite's highest strength (EFB3) was 183 MPa, its modulus was 5.9 GPa, and its flexural strength and modulus were 216 MPa and 6.1 GPa, respectively. The impact intensity is 8 J, and the hardness value is 95 on the Shore D scale. In addition, the EFB3 had a maximum interlaminar shear strength of 35 MPa. According to the findings of the SEM surface analysis, the matrix molecules exhibit adhesion to the fiber, which indicates increased bonding. The thermal conductivity and dielectric properties were high for composite with higher biochar particle content. These waste biomass‐converted fruit fiber biochar and curtain climber industrial crop fiber epoxide composite materials may be utilized in a variety of sectors, including aerospace, automotive, household domestic product manufacturing, and defense sectors.Highlights Extraction and silane treatment of curtain climber fiber. Producing biochar from waste biomass Kigelia pinnata fiber. Fabrication of polyepoxide composite. Siloxane layer improves the strength. Biochar improves the properties of composites.

Glass flakes for enhancing mechanical properties of glass/epoxy composites

The purpose of this study is to improve composite mechanical properties by reducing the degradation induced by seawater in glass fibre/epoxy composites. To do this, glass flakes (50 µm in size) were placed on the surfaces of the glass fibre/epoxy composite material using various ratios (5%–15%). Glass flakes were introduced into composite materials that were exposed to seawater for a period ranging from 0 to 12 months, and changes in bending, tensile, impact, compression, and compression after impact strengths were assessed. Flexural tests revealed that the gel coat and glass flakes increased their loads by up to 24% and 23% after 6 and 12 months of water immersion, respectively. Tensile tests indicated that lower tensile strength loss occurred as the glass flake ratio rose. As the immersion duration increased, the effect of glass flakes became more evident in terms of tensile strength. Composites containing glass flakes showed greater impact strength load values in both 20 and 30 J impacts compared to the control sample. The use of glass flakes improved the residual strength values because it prevented water penetration. The control sample retained up to 50% of its compressive strength, while the 15% glass-flake reinforcement promoted retention to 56%.

Bo-derived waste neem to enriching reinforced hybrid composite for environmental remediation

The utilization of natural fibres often entails a lesser environmental impact when compared to synthetic fibres. Biodegradable natural fibres minimize waste and pollution, and promote sustainability, but their weaker bonds limit their resilience. These issues can be addressed by customizing the composite's mechanical properties with natural and synthetic fibres. In this study, hybrid composites were created using the hand layup method with a novel dissimilar layer arrangement of neem (N), sisal (S), and glass (G) fibre and analyze its mechanical and thermal properties. Experimental observation shows that the GN composite had a higher maximum ultimate tensile strength of 26 N/mm2 than the GS, GNS, and GSN composites. The GN composite had a percentage elongation of 6.33%, similar to the percentage elongation of the GS composite (6.833%), and it also had a higher ultimate shear strength of 50 MPa. The composite GS absorbed 6.6 J energy, higher than the composites GN, GNS, and GNS, which absorbed 6.1 J, 4.5 J, and 4.5 J, respectively. The fractured surface's SEM images were obtained and analyzed for failure. The results demonstrated that the hybridization was effective, and better properties can be obtained by combining neem, sisal, and glass fiber, and it can be used for other requirements, including strength, weight, cost, and ecological impact.

Mechanical property distribution of composites considering cured ply thickness variability

Variability is an essential feature of composites and directly affects the application of composite structures. Only a few studies have been conducted on the mechanical properties of composites considering cured ply thickness variability. This paper analyses the phenomena of cured ply thickness and the mechanical properties of materials obeying normal distribution after normalization. The distribution function and probability density function of the mechanical properties of composites considering the variability of cured ply thickness are derived. The correctness of the derived distributions is verified by Monte Carlo simulation, which compares the distribution of mechanical properties of composites after normalization with that considering the variability of cured ply thickness. The results showed that after considering the cured ply thickness variability, the mechanical properties showed a skewed distribution. At the lower percentile of the distribution, the mechanical properties are low compared to the normalized values, which reduces the permissible values of the composites.

Effect of fiber content on mechanical properties of carbon fiber-reinforced polyether-ether-ketone composites prepared using screw extrusion-based online mixing 3D printing

The mechanical properties of carbon fiber-reinforced polyether-ether-ketone (CF/PEEK) composites are closely related to the fiber content. However, the low fiber content (typically below 20 wt%) that can be prepared by current material extrusion limits the application of the composites. In this work, CF/PEEK composites with up to 50 wt% carbon fiber content were manufactured using a custom-made screw extrusion-based online mixing 3D printhead. The impact of fiber loading on the rheological and flow characteristics of the composites was thoroughly examined initially. Subsequently, the influence of fiber content on the crystallinity and mechanical behavior of 3D-printed parts before and after annealing was further explored. The results indicated that adding CF and annealing significantly enhanced the strength and modulus of the 3D-printed composites within a fiber content range of 10 wt% to 40 wt%, compared to those of pure PEEK. At 40 wt% CF, the tensile and flexural strengths of the samples reached their maximum values at 135.9 MPa and 251.2 MPa, respectively, which were enhanced by 94% and 111% compared to those of the unannealed pure PEEK specimens. Also, these properties are the highest values achieved in 3D-printed short CF/PEEK composites. The mechanical properties of composites are affected by various factors such as fiber content, crystallinity, and internal pore defects when the fiber content is less than 20 wt%. However, when the fiber content exceeds 20 wt%, the influence of crystallinity on the mechanical properties becomes less significant. This study further explores the potential application of CF/PEEK composites and provides a novel approach for composite preparation.