Mechanical Properties Of Epoxy Composites Research Articles

Effect of alumina fillers on physical and mechanical properties of luffa/groundnut shell natural fiber reinforced polymer composites

AbstractThis study aims to investigate the physical and mechanical properties of epoxy composites reinforced with hybrid luffa waste and groundnut shell waste natural fibers and to evaluate the effect of different filler loadings of alumina on the mechanical behavior of the hybrid composites. The luffa fibers were made to undergo mercerization in 10% NaOH solution. All the treated fibers and the alumina fillers were characterized using X‐ray diffraction analysis (XRD). The study used three different filler loadings of alumina (Al2O3) (5%, 10%, and 15% by volume) and three different fractions of treated luffa‐waste groundnut shell hybrid fibers (10%, 30%, and 50% by volume). The composites were fabricated using the hand layup technique, and the prepared test specimens were subjected to mechanical and physical properties testing as per ASTM standards. The experimental findings indicated that the inclusion of Al2O3 filler improved the physical and mechanical characteristics of the natural fiber‐reinforced hybrid composites. The results showed that the composites with 30 vol. % fibers (1:1 luffa fiber: groundnut shell fiber) and 10 vol. % Al2O3 content showed enhanced tensile, flexural, shear, and impact strength and hardness. Besides, a good synergy between the alumina fillers, natural fibers, and the polymer matrix was observed in the surface morphology of the composite specimen. The developed composites can be used in low and medium‐load‐bearing structural and non‐structural applications.Highlights Development of hybrid polymer composites with luffa and novel groundnut shell fibers Hybridization of alumina ceramic particles with natural fiber hybrid composites Assessment of physical and mechanical properties of the polymer composites

Investigation of the mechanical and physical properties of mesoporous silicon dioxide fillet epoxy composites

In this study, the effect of mesoporous silicon dioxide (M-SiO2) additives with different surface areas and pore diameters on the morphological and mechanical properties of epoxy composites was investigated. For this purpose, M-SiO2 particles with different pore diameters and surface areas were synthesized from polyethylene glycol (PEG) with three different molecular weights (PEG2000 (PEG2), PEG6000 (PEG6), and PEG35000 (PEG35) kDa) using the one-step sol-gel technique. The mixing of epoxy resin, hardener and M-SiO2 fillers, was carried out in a mould followed by using ultrasonic bath and mechanical stirrer.The mechanical properties of the composites, including hardness, tensile strength, elongation at break, and modulus of elasticity, were studied. FT-IR spectra and XRD patterns show that M-SiO2 is distributed homogeneously in the epoxy. The epoxy/PEG35M-SiO2 composites' tensile strength (8.7%) and modulus of elasticity (23.3%) increased with the addition of PEG35M-SiO2, however their elongation at break (5.1%) decreased.

Investigation of fracture behavior and mechanical properties of epoxy composites supported with MWCNTs microscopically

Adding of a multi-walled carbon nanotubes (MWCNTs) to epoxy resin has shown promising results in improving fracture toughness in bulk epoxy and carbon fiber-reinforced epoxy composites (CFRP). using a hand layup proceeding followed by the so called vacuum bagging process method, carbon fiber-reinforced polymer multi-wall carbon nanotubes (MWCNTs) was added to an epoxy resin with a weight percentage mixing of 1% wt., 1.25% wt., and 1.5 % wt. MWCNTs. Furthermore, the specimen underwent analysis via Fourier-Transform Infrared (FTIR) spectroscopy, and X-ray Diffraction (XRD) spectroscopy, the composites were subjected to a microscopic examination using a Scanning Electron Microscope (SEM). FTIR and XRD verified the folding and unfolding of the polymer, in addition, the mechanical properties including tensile strength, bending stress, and impact behavior were investigated as well as the hardness test. The obtained results showed a significant improvement of about (40 %) in tensile strength, (53 %) in bending stress at 1 % wt. MWCNTs, and (70 %) percentage increment in the strength of Impact at 1.25 % wt. MWCNTs. And the gained hardness was about 40.5 HV which were compared with a reference substance named Carbon Fiber (CF) without any addition of nano materials. Carbon nanotubes have demonstrated their potential to enhance the mechanical properties of fiber-reinforced polymers, so this investigative study employs comprehensive characterization techniques, and demonstrates significant improvements in mechanical properties for the modified polymeric composite materials supported with nano materials.

Mechanical properties of epoxy composites reinforced with Areca catechu fibers containing silicon carbide

The physical and chemical attributes of Areca catechu fiber (ACF) were explored. ACF is attractive because of its high cellulose content at 63.2 wt%. The mechanical properties were evaluated for Areca catechu fiber-reinforced epoxy composites, in which silicon carbide (SiC) was used as filler. The studied properties included water absorption, flexural strength, impact strength, tensile strength, and hardness properties. The tensile and flexural properties improved when the filler content increased from 40 to 50 wt%, but further increment in the filler content reduced the strength values. The addition of SiC adversely affected the bending and flexural properties of the composites at 40 and 50 wt% filler content, but it positively affected the properties at 60 wt% filler content. The hardness of the composites increased with the addition of 10% silicon carbide. From the results of this study, it is recommended that the ratio of silicon carbide in the composite should not exceed 10 wt% due to agglomeration. The composites containing 10 wt% SiC can be used for outdoor applications such as decking, railing, garden fencing, cladding, and siding applications.

Evaluation of mechanical properties of hybridised coir-carbon-basalt reinforced epoxy composites

ABSTRACT The present work focuses on the evaluation of the mechanical properties of epoxy composites reinforced with coir/carbon/basalt fibres. Reinforcements were used in as-received condition without any surface modifications. Composites were subjected to tensile, flexural and impact tests as per ASTM standards. Water absorption analysis was performed on the prepared composites using normal, salt and distilled water. The highest void fraction of 0.57% was obtained for the composite reinforced with carbon and basalt fibres. Highest tensile strength and modulus of 280 and 2500 MPa were achieved for composites reinforced only with carbon fibres. Hybrid composites fabricated using carbon fibres as outer layers and basalt as inner layers exhibited the highest flexural strength of 55 MPa. Composites reinforced only with basalt fibres displayed maximum impact strength of 22.64 kJ/m2 among the tested laminates. Inclusion of coir fibres significantly reduces tensile strength and modulus by 92.86% and 90%; flexural strength and modulus by 90.91% and 82%; impact strength by 71.74%, respectively. Composites reinforced only with basalt fibres absorbed more water than other combinations under all testing conditions. Scanning electron micrographs showed better interfacial bonding between synthetic fibres and the matrix as compared to natural fibre-reinforced composites.

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.

Electrical and Mechanical Properties of Epoxy Composites Filled with Carbon and Co3O4 Nanoparticles

Electrical and Mechanical Properties of Epoxy Composites Filled with Carbon and Co3O4 Nanoparticles

Simultaneously enhancing tribological and mechanical properties of epoxy composites using basalt fiber/reduced graphene oxide/paraffin wax

AbstractEpoxy composites with simultaneously enhanced tribological and mechanical properties filled with basalt belt/reduced graphene oxide/paraffin wax (EP/BF/RGO/PW) have been successfully prepared. Experimental results indicated that the mechanical property of the composites was reinforced by basalt belt, and the tribological property was greatly improved by reduced graphene oxide/paraffin wax at the same time. Thanks to the synergy of PW and RGO sheets, the optimized coefficient of friction and wear rate of the composite declined by 77.5% and 14.4% than pure EP under dry friction conditions of 60 N and 0.42 m s−1. In comparison to pure EP, the tensile strength and modulus of the optimized composite increased by 75.5% and 100% on account of the robust basalt fibers. Thus, the combination of basalt fiber and reduced graphene oxide/paraffin wax can readily realize the introduction of enhancer and oil‐impregnation in EP, offering a promising approach for simultaneously improving the mechanical and tribological properties of epoxy.Highlights A novel BF/RGO/PW 3D skeleton was developed via a facile hydrothermal method. The BF/RGO/PW can enhance the mechanical and tribological properties of EP. The basalt fibers account for the improvement in mechanical property. A reduction of 77.5% in COF and a decrease of 14.4% in wear rate were realized.

Non-Covalent Functionalization of Graphene Oxide with POSS to Improve the Mechanical Properties of Epoxy Composites.

Phenyl polyhedral oligomeric silsesquioxane (POSS) is modified onto the GO surface by using the strong π-π coupling between a large number of benzene rings at the end of the phenyl POSS structure and the graphite structure in the GO sheet, realizing the non-covalent functionalization of GO (POSS-GO). The POSS-GO-reinforced EP (POSS-GO/EP) composite material is prepared using the casting molding process. The surface morphology of GO before and after modification and its peel dispersion in EP are examined. Furthermore, the mechanical properties, cross-sectional morphology, and reinforcement mechanism of POSS-GO/EP are thoroughly examined. The results show that the cage-like skeleton structure of POSS is embedded between the GO layers, increasing the spacing between the GO layers and leading to a steric hindrance effect, which effectively prevents their stacking and aggregation and improves the dispersion performance of GO. In particular, the 0.4 phr POSS-GO/EP sample shows the best mechanical properties. This is because, on the one hand, POSS-GO is uniformly dispersed in the EP matrix, which can more efficiently induce crack deflection and bifurcation and can also cause certain plastic deformations in the EP matrix. On the other hand, the POSS-GO/EP fracture cross-section with a stepped morphology of interlaced "canine teeth" shape is rougher and more uneven, leading to more complex crack propagation paths and greater energy consumption. Moreover, the mechanical meshing effect between the rough POSS-GO surface and the EP matrix is stronger, which is conducive to the transfer of interfacial stress and the strengthening and toughening effects of POSS-GO.

Mechanical Properties of Epoxy Composites Reinforced Using a Carbon Fiber Film Type Coated with Carboxyl Graphene via an Economical Electrophoretic Deposition Technique

Mechanical Properties of Epoxy Composites Reinforced Using a Carbon Fiber Film Type Coated with Carboxyl Graphene via an Economical Electrophoretic Deposition Technique

Influence of Layering Pattern, Fibre Architecture, and Alkalization on Physical, Mechanical, and Morphological Behaviour of Banana Fibre Epoxy Composites

In the current investigation, the mechanical properties of epoxy composites reinforced with banana pseudostem fibres, specifically focusing on tensile and impact behaviour, are investigated. The manufacturing process employed the meticulous hand-lay-up technique to fabricate six distinct samples. These samples included various combinations of short and woven banana fibres, treated and untreated, as well as a hybrid configuration involving layers of woven and short fibres. A fixed weight ratio of 60% fibres to 40% epoxy matrix was maintained for consistency. To ensure optimal material integrity, a careful application of resin and hardener in a 10 : 1 weight ratio was layered, with each addition of fibre followed by thorough rolling to eliminate any potential bubbles. The density and void fraction of the resulting composites were meticulously assessed to gauge the influence of this layering approach. Additionally, an X-ray diffraction (XRD) analysis was conducted to ascertain the impact of the chemical treatment on the cellulose content of the fibres. Our findings revealed that the tensile and impact properties were notably superior in the woven fibre composites. In particular, the chemically treated woven banana fibre epoxy composite displayed impressive values of 64.95 MPa for tensile strength and 24.37 KJ/m2 for impact strength. To gain deeper insights into the structure-property relationship, test specimens were analyzed using scanning electron micrographs. Lastly, comparative analysis by mapping the tensile properties from our present work with those from existing studies was carried out.

In Situ-Generated Heat-Resistant Hydrogen-Bonded Organic Framework for Remarkably Improving Both Flame Retardancy and Mechanical Properties of Epoxy Composites.

In this study, the heat-resistant hydrogen-bonded organic framework (HOF) material HOF-FJU-1 was synthesized via in situ generation and then used as flame retardants (FRs) to improve the flame retardancy of epoxy resin (EP). HOF-FJU-1 can maintain high crystallinity at 450 °C and thus function as a flame retardant in EP. The study found that HOF-FJU-1 facilitates the improvement of char formation in EP, thus inhibiting heat transfer and smoke release during combustion. For EP/HOF-FJU-1 composites, the in situ-generated HOF-FJU-1 can remarkably improve both the mechanical properties and the flame retardancy of EP. Furthermore, the in situ-generated HOF-FJU-1 has better fire safety than the ex situ-generated HOF-FJU-1 at the same filling content. Thermal degradation products and flame retardation mechanisms in the gas and condensed phases were further investigated. This work demonstrates that the in situ-generated HOF-FJU-1 is promising to be an excellent flame-retardant candidate.

A review on functionalization methods of graphene oxide for enhancement in mechanical properties of epoxy composites

In recent years the use of Graphene Oxide (GO) in composite materials is growing in engineering applications. However, the major drawback of adding Graphene Oxide (GO) inhibits the bonding between the matrix and the reinforcement which reduces the load transfer. Due to this reason, there is a need for functionalization of Graphene Oxide. Graphene oxide is a highly reactive grapheme derivative having nucleophiles. In this study different types of covalent and non-covalent bonding functionalization methods of GO for dispersion in epoxy composites are discussed with their preparation and characterization. A comparative analysis of GO gives understanding of methods of functionalization affect with respect to mechanical and chemical properties. This study gives variety of processes involved and its influence on mechanical and chemical behaviour of the epoxy composites. Among all the methods mentioned for functionalization of GO, Amino-siloxane (APS), Polyethyleneimine (PEI) and triton shows effective results in improvement of mechanical properties.

Effect of Phosphorus and Chlorine Containing Plasticizers on the Physicochemical and Mechanical Properties of Epoxy Composites

The possibility of using tris(2-chloroethyl) phosphate, tris(1-chloro-2-propyl) phosphate and tris(4-methylphenyl) phosphate as effective plasticizers for epoxy polymers has been studied. As a result of the research the optimum content of plasticizers (40 parts by mass) has been determined, which has the best effect on the strength and fire safety properties of epoxy composites. Modification of the epoxy polymer with presented plasticizers influences carbonization process increasing char yield and reducing the amount of volatile thermolysis products released into the gas phase, thus improving fire safety parameters of epoxy composites, reducing mass loss on ignition in air from 78 to 2–9% and increasing limiting oxygen index (LOI) values from 19 to 25–31% by volume, giving good fire protective properties to epoxy composites (UL-94 rating—V-0/V-1). The thermo-protective properties and the structure of the char formed by polymer combustion have been studied and the correlation between the thermo-protective properties of the char and the combustibility of the composite has been determined. Furthermore, the behaviour of the modified composite during high rate pyrolysis has been analyzed.

High mechanical performance of 3-aminopropyl triethoxy silane/epoxy cured in a sandwich construction of 3D carbon felts foam and woven basalt fibers

Abstract Epoxy-based sandwich composites with improved economic efficiency were developed to better utilize composite components with functions such as high mechanical performance and light weight, which influenced quality for load-bearing applications. Herein, an epoxy-based sandwich composite was made by laminating woven basalt fibers (WBFs) as a face sheet on 3D carbon felt foam (3D CFs) as a core material. The cast-in-place process was used to infuse the epoxy solution within the sandwich, resulting in bicontinuous composites with outstanding mechanical characteristics and high performance. In addition, the epoxy solution was combined with a silane coupling agent to boost the composite’s toughness by enhancing the adhesion between the fibers and the epoxy. The mechanical properties of epoxy composites were also found to be much improved when WBFs were used as a face on 3D CF foam. Compared to the epoxy/3DCFs/WBFs composite sandwich to pure epoxy, the flexural and tensile strengths improved by 298.1 and 353.8%, respectively, while the impact strength rose to 135 kJ/m2. This research shows a new way to make a new process for making sandwich composites with epoxy that is cheap and strong.

Electrical and Mechanical Properties of Epoxy Composites Reinforced with Kaolin-Coated Basalt Fibers

Electrical and Mechanical Properties of Epoxy Composites Reinforced with Kaolin-Coated Basalt Fibers

Dynamic Mechanical Properties of Epoxy Composites Modified with Polysulphide Rubber

Harbin Institute of Technology, 92 Xidazhi street, Nangang District, Harbin, Heilongjiang Province, People's Republic of China

The Synergistic Effects of Hybrid Micro and Nano Silica in Influencing the Mechanical Properties of Epoxy Composites-A New Model.

HighlightsMicro silica and nano silica are found to yield similar effects in influencing the values of Young’s modulus.The values of Young’s modulus of hybrid silica particle are higher than single filler, at the same weight loading.The highest improvement in Young’s Modulus was recorded 25 wt.% hybrid loading (12.5 wt.% micro silica + 12.5 wt.% nano silica).1.1 weight percentage is applied for the hybrid composite, which makes equal distribution of weight for nano and micro.Epoxy nano composites containing micro and nano silica were prepared by varying the filler’s weight loading as an attempt to investigate the effects of incorporating these fillers in influencing its mechanical properties. Mechanical properties characterizations include the evaluation of tensile. The mechanical properties of the epoxy composites were found to tremendously increase as both micro and nano silica were added together at a 1:1 wt.% ratio. For example, the highest values of Young’s modulus were recorded to be 5.39 GPa for 25 wt.% loading (12.5 wt.% Micro + 12.5 wt.% nano), while Young’s modulus values of 5.22 MPa and 5.32 MPa were recorded for micro and nano silica, respectively, at the same weight loading. The most outstanding results were observed at 25 wt.% hybrids (12.5 wt.% micro silica + 12.5 wt.% nano silica), where the values of Young’s modulus were increased by 228% compared to the neat epoxy. This study successfully demonstrated synergistic effects demonstrated by combining micro and nano silica fillers, which created an interaction that significantly enhanced the Young’s modulus of epoxy composites.

Graphene oxide/epoxy composites with enhanced fracture toughness for liquid hydrogen storage

AbstractGraphene oxide (GO)/epoxy composites cured by aliphatic dibasic acids have been prepared. The influences of structure of aliphatic dibasic acid and loading of GO on curing process and mechanical properties of epoxy composites were studied. The results show that the reaction activities, gel time of corresponding epoxy‐acid system and tensile strength of the formed epoxy resins decrease with the increase of the chain length of aliphatic dibasic acids. Both fracture toughness (>1.96 MPa⋅m1/2) and elongations at break (>6%) increase with the increase of the chain length of aliphatic dibasic acids. The introduction of GO is helpful to increase the mechanical properties and the gas transmission coefficient of GO/epoxy composites. A maximum of tensile strength and elongations at break were obtained when the loading of GO is 0.6 wt%. The gas transmission coefficient of GO/epoxy composite increases with the increase of GO loading. The excellent mechanical properties and gas leakage resistance coefficient of the formed epoxy composites provides potential application in many fields where conventional brittle epoxy resins are inapplicable.

Comparison of the Influence of Two Types of Plasma Treatment of Short Carbon Fibers on Mechanical Properties of Epoxy Composites Filled with These Treated Fibers.

The interfacial interface between fibers and matrix plays a key role for epoxy matrix composites and short recycled randomly arranged fibers. This study used short recycled carbon fiber (RCF) as a filler. Plasma treatment was used for carbon fiber surface treatment. This treatment was performed using radio (RF) and microwave (MW) frequencies at the same pressure and atmosphere. Appropriate chemical modification of the fiber surfaces helps to improve the wettability of the carbon fibers and, at the same time, allows the necessary covalent bonds to form between fibers and the epoxy matrix. The effect of the plasma treatment was analyzed and confirmed by X-ray photoelectron spectroscopy, Raman microscopy, scanning electron microscopy, transmission electron microscopy and wettability measurements. Composite samples filled with recycled carbon fibers with low concentrations (1 wt%, 2.5 wt% and 5 wt%) and high concentrations (20 wt% and 30 wt%) were made from selected treated fibers. The mechanical properties (impact toughness, 3PB) were analyzed on these samples. It was found that the modulus of elasticity and bending stress increase with the increasing content of recycled carbon fibers. A more significant change in impact strength occurred in samples with low concentration.