Thermal Properties Of Epoxy Composites Research Articles

A study of the friction and thermal properties of epoxy composites synergistically reinforced by open-celled Cu foams and carboxylated CNTs

A study of the friction and thermal properties of epoxy composites synergistically reinforced by open-celled Cu foams and carboxylated CNTs

Enhanced morphological and thermal properties of epoxy composites reinforced with Palm and Prosopis Juliflora fibers

Abstract This study investigates the fabrication and characterization of a hybrid epoxy matrix composite reinforced with Palm and Prosopis Juliflora fibers fabricated using the hand layup technique. Three composite samples were prepared with varying weight percentages of palm and Prosopis Juliflora fiber reinforcements: 5% (Sample A), 10% (Sample B), and 15% (Sample C). Sample B having 10 weight percentage each of Palm fiber and Prosopis Juliflora fiber and 80 weight percentage of Epoxy matrix, exhibited superior performance with a tensile strength of 45.5 MPa and a hardness of 86.5 Shore D. Thermal analysis revealed Sample B’s exceptional thermal stability, with distinct decomposition stages observed through Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). Void content analysis indicated Sample C had the lowest void content at 4.5%. Energy Dispersive x-ray (EDX) Analysis confirmed homogeneous fiber distribution and strong fiber-matrix adhesion, supported by carbon and oxygen peaks. Fourier-transform infrared spectroscopy (FTIR) spectra showed interactions between functional groups, including alcohols, carboxylic acids, and carbonyl compounds. These findings underscore the composite’s potential for high strength, toughness, and thermal stability applications.

A comprehensive experimental study on the effects of hexagonal boron nitride particle size and loading ratio on thermal and mechanical performance in epoxy composites

Harnessing the potential of hexagonal boron nitride (h-BN) in epoxy composites for tailoring thermal conductivity is a promising avenue in materials science. However, achieving balanced enhancements in both in-plane and through-plane directions remains a challenge that requires innovative solutions. The primary objective of this research is to evaluate how thermal and mechanical characteristics of an epoxy matrix are affected by the size and amount of h-BN particles. To achieve this goal, h-BN particles with varying sizes (micro and nano) are incorporated into the epoxy matrix at different weight ratios spanning from 0.5 wt % to 20 wt % using a pre-dispersion technique. The epoxy composites reinforced with h-BN through a molding process exhibits enhanced mechanical and thermal performance in contrast to the pristine epoxy material. During the flexural test, acoustic emission data is collected to identify the initiation and progression of damage within the specimens under testing conditions. The most notable enhancement in thermal conductivity is observed when incorporating 20 wt% of micron-sized h-BN particles. This leads to a remarkable 107% increase in the in-plane direction and an impressive 112% increase in the through-plane direction. These results can be attributed to the formation of a three-dimensional thermally conductive network by the larger h-BN particles, which extends the path of phonon scattering. Furthermore, there are significant improvements in both flexural modulus and tensile modulus. Epoxy composites containing 10 wt% of micron-sized h-BN experiences an approximate 42% increase, while those with 20 wt% of the same particles displays a substantial 47% rise in these properties. This study effectively addresses the challenges associated with tailoring the thermal properties of epoxy composites, opening up new opportunities for applications in various industries, including electronics, aerospace and thermal management systems.

Evaluation of physical, mechanical and thermal properties of epoxy composites filled with bio-fiber derived from Bambara nut shell filler

Evaluation of physical, mechanical and thermal properties of epoxy composites filled with bio-fiber derived from Bambara nut shell filler

Enhancing Mechanical and Thermal Properties of Epoxy Composites with Fish Scale‐Derived Collagen Reinforcement

Epoxy polymer composites reinforced with fish scale‐derived collagen (EFC) have garnered significant interest due to their potential for enhancing mechanical properties and environmental sustainability. In this study, we investigated the mechanical, thermal, and morphological characteristics of epoxy composites reinforced with varying concentrations of EFC (5%, 10%, 15%, 20%, and 25% wt). Tensile strength testing revealed an initial increase in Young’s modulus with 5% and 10% EFC concentrations, followed by a decrease at higher concentrations, attributed to agglomeration effects. Flexural strength (FS) exhibited a decreasing trend with increasing EFC content, while flexural modulus (FM) showed improvement up to 20% EFC loading. Scanning electron microscopy (SEM) analysis highlighted the distribution of collagen particles, with agglomeration observed at higher concentrations. Fourier‐transform infrared spectroscopy (FTIR) spectroscopy indicated alterations in hydrogen bonding with the addition of EFC. Thermal analysis revealed a reduction at onset degradation temperature with EFC incorporation, attributed to poor dispersion and agglomeration effects, alongside a slight enhancement in thermal stability at higher concentrations. The study supports the sustainable use of EFC as a filler, by offering a renewable and eco‐friendly alternative to reinforcing polymer composites.

Investigation of Dielectric, Mechanical, and Thermal Properties of Epoxy Composites Embedded with Quartz Fibers.

Polymer matrix wave transparent composites are used in a variety of high-speed communication applications. One of the applications of these involves making protective enclosures for antennas of microwave towers, air vehicles, weather radars, and underwater communication devices. Material performance, structural, thermal, and mechanical degradation are matters of concern as advanced wireless communication needs robust materials for radomes that can withstand mechanical and thermal stresses. These polymer composite radomes are installed externally on antennas and are exposed directly to ambient as well as severe conditions. In this research, epoxy resin was reinforced with a small amount of quartz fibers to yield an improved composite radome material compared to a pure epoxy composite with better thermal and mechanical properties. FTIR spectra, SEM morphology, dielectric constant (Ɛr) and dielectric loss (δ), thermal degradation (weight loss), and mechanical properties were determined. Compared to pure epoxy, the lowest values of Ɛr and δ were 3.26 and 0.021 with 30 wt.% quartz fibers in the composite, while 40% less weight loss was observed which shows its better thermal stability. The mechanical characteristics encompassing tensile and bending strength were improved by 42.8% and 48.3%. In high-speed communication applications, compared to a pure epoxy composite, adding only a small quantity of quartz fiber can improve the composite material's dielectric performance, durability, and thermal and mechanical strength.

Enhanced thermal properties of epoxy composites by constructing thermal conduction networks with low content of three-dimensional graphene

Micro/nano electronic devices heat dissipation depends heavily on the thermal interface materials (TIMs). Despite notable progress, it is hard to efficaciously enhance the thermal properties of the hybrid TIMs with high-load additives due to an absence of effective heat transfer routes. Herein, the low content of three-dimensional (3D) graphene with interconnected networks is adopted as the additive to improve the thermal properties of epoxy composite TIMs. The thermal diffusivity and thermal conductivity of the as-prepared hybrids were dramatically improved by constructing thermal conduction networks after adding 3D graphene as fillers. The 3D graphene/epoxy hybrid’s optimal thermal characteristics were observed at 1.5 wt% of 3D graphene content, corresponding to a maximum enhancement of 683%. Besides, heat transfer experiments were further performed to determine the superb heat dissipation potential of the 3D graphene/epoxy hybrids. Moreover, the 3D graphene/epoxy composite TIM was also applied to high-power LED to improve heat dissipation. It effectively reduced the maximum temperature from 79.8 °C to 74.3 °C. These results are beneficial for the better cooling performance of electronic devices and provide useful guidelines for advancing the next-generation TIMs.

Thermal properties of epoxy composites with polyaniline and graphene nanofiller

Thermal properties of epoxy composites with polyaniline and graphene nanofiller

A carbon nanosphere nanofluid for improving the toughness and thermal properties of epoxy composites

A carbon nanosphere nanofluid (CNS-nanofluid) was successfully prepared through the non-covalent modification of carbon nanosphere (CNS) with the specific ionic liquid (i.e. [M2070][VBS]) at first. The resulting CNS-nanofluid is a homogeneous and stable fluid with liquid-like behaviour at room temperature, and which shows better dispersion stability in its good solvents and improved processability than the pristine CNS. Subsequently, this CNS-nanofluid was used as a kind of novel functional filler and incorporated into epoxy matrix to prepare the CNS-nanofluid filled epoxy composites (CNS-nanofluid/EP composites). The toughness and thermal properties of those CNS-nanofluid/EP composites were carefully characterized and analysed. And it was found that this CNS-nanofluid could respectively improve the impact toughness and glass transition temperature of the CNS-nanofluid/EP composites to 19.8 kJ m−2 and 122.5 °C at the optimum amount, demonstrating that this CNS-nanofluid is a kind of promising functional filler to achieve robust epoxy composites, and thus opening up new possibilities with great significance for epoxy composites in high-performance applications.

Preparation and study of some mechanical and thermal properties of epoxy composites with natural styrene butadiene rubber (damaged tires)

A composite material was prepared from epoxy resin as a base material with the reinforcing materials (natural and synthetic styrene butane rubber) with different weight percentages and different results were obtained depending on the added weight percentages of the reinforcing material, and the effect was clear on the values of mechanical properties and thermal conductivity. The values of the hardness, shock and compressive strength increased after the reinforcing process, but the relationship was inverse between the hardness and compressibility with temperature. As for the shock resistance, it increased with an increase in temperature to 55 °C. As for the thermal conductivity, it decreased when adding natural styrene butadiene and increased by only one degree when adding synthetic styrene butadiene. It is noted that the results that appeared when adding natural styrene butadiene rubber as a reinforcement material is better than the reinforcement by means of synthetic styrene butadiene.

Novel Conductive Polymer Composites for Asphalt Pavement Structure in Situ Strain Monitoring: Influence of CB/CNT and GNP/CNT Nano/Micro Hybrid Fillers on Strain Sensing Behavior

Sensing materials and devices with high sensitivity are necessary for engineering structure monitoring with the rapid development of intelligent infrastructure. This paper provides a novel approach to develop strain sensor with high sensitivity for pavement deformation monitoring by epoxying composites with hybrid nano/micro fillers. The effect of combined carbon black/carbon nanotubes (CB/CNT), graphene nanoplatelet/carbon nanotubes (CNT/GNP) fillers on the self-sensing behavior, morphology, dynamic mechanical performance and thermal properties of epoxy composites was discussed in detail. The incorporation of secondary CB results in significant improved self-sensing ability in micro-strain range. CB-CNT hybrid fillers show positive synergy effect on enhancement of piezoresistive response, while GNP show less positive effect on sensing behavior. The presence of CB forms the conductive core domain surrounded by CNT and constructs the multi scale conductive network of composites. The addition of two secondary fillers improves dynamic mechanical performance of composites. The self-sensing behavior of composites with combined filler was illustrated by SEM morphology and conductive pathway evolution during tensile deformation. Laboratory test showed that relative resistance changes have a linear relationship with the strain for developed sensor embedded in asphalt mixture. The polymer composite sensor shows strong sensing ability for asphalt concrete strain monitoring.

Numerical Investigation of Iron Ore Tailings Filled Epoxy Composite as Heat Resistant Material

The thermal properties of epoxy composites reinforced with iron ore tailings were used to investigate the thermal performance of the composite as heat resistant material. Thermal properties are important parameters for determining the behaviour and appropriate applications of materials. This paper focuses on investigating the thermal performance of epoxy composite reinforced with iron ore tailings (IOT) of particles sizes 150 µm, 10% reinforced. The thermal properties of the selected epoxy-IOT composite were specific heat capacity – 2352 J/kg-K, thermal resistivity – 4.788 °C-m/W, thermal diffusivity – 0.089 mm2/s and Thermal conductivity – 0.209 W/m-K. The selected epoxy-IOT composite was numerically compared with an existing material (gypsum board) of the following thermal properties: specific heat capacity – 1090 J/kg-K, thermal resistivity – 3.87°C-m/W, thermal diffusivity – 0.333 mm2/s and Thermal conductivity – 0.258 W/m-K. The numerical analysis was done using Autodesk Fusion360, by modelling the materials as slabs.The heat transfer process of the composite and the prediction of the heat resistance capability were explained by comparing the results with an existing material (gypsum plasterboard) using their mechanical and thermal properties.The numerical results indicated that the epoxy-IOT composite has lower minimum temperature and thermal stress compared with the existing material (gypsum board), which implies that epoxy-IOT composite when used as a heat insulator will resist heat and sustain thermal stress better than the gypsum board of the same geometry under the same conditions. In conclusion, an epoxy-IOT composite of appropriate mixing ratio and geometry can be comfortable use as heat resistant materials. Keywords— Epoxy-IOT, Numerical Analysis, Temperature Distribution, Thermal Performance, Thermal Stress

Enhanced thermal conductivity of epoxy composites by constructing thermal conduction networks via adding hybrid alumina filler

AbstractHigh thermal conductivity of polymer composites could be achieved through constructing 3D continuous thermally conductive networks into polymer composites. Herein, we demonstrate a simple, effective method to optimize the segregated alumina networks by using ternary mixture of alumina particles with different diameter ratios (5.8 μm + 2.6 μm + 0.5 μm) at the fixed total content of 60 wt% via conventional melt blending method. The thermal properties of epoxy composites were investigated as a function of the weight fraction and particle size of alumina particles. The thermal conductivity (TC) values of composites with coarse fillers (13.2 μm) are in agreement with Agari model at high filler loading (57 ~ 67 wt%). And the value of C2 was ~0.949 (close to 1), indicating that the formation of heat conduction paths in the composites. The addition of 60 wt% smaller fillers (2.6 μm) facilitates a higher interaction degree between the polymer/fillers, consequently, leads to a higher Tg of 147.8°C. A high TC of 1.109 W m−1 K−1 is achieved as the ratio of alumina filler with different particle sizes is 7/2/1, corresponding to a TC enhancement of 23%–32% compared to the composites with a single particle size filler. A suitable proportion of hybrid fillers is crucial for constructing three‐dimension continuous network, in which nano‐particles filled between the micro‐particles could increase the particle‐to‐particle connectivity.

Effect of organic-modified nickel phyllosilicates on the tribological, mechanical and thermal properties of epoxy composites

The present study aims at investigating the effect of organic-modified nickel phyllosilicate (NiPS) particles on the structure–property relationships of epoxy (EP) composites. The organic-modified NiPS particles were synthesized using a facile sol–gel method and subsequently mixed into EP matrix by physical blending to improve its tribological, mechanical and thermal properties. Based on a series of tests and analyses, it was found that organic-modified NiPS particles playing a great role in improving the tribological properties under dry sliding. The steady-state friction coefficient was just decreased moderately, whereas the wear rate was dropped significantly to 0.36 × 10 −5 mm 3 /N·m, showing a reduction up to ca. 95% in comparison with pure EP. According to the analysis of worn surfaces, the main mechanism of wear resistance was discussed. The elastic modulus for the EP composites was increased remarkably while the elongation at break decreased. However, the added organic-modified NiPS particles show a negligible influence on the tensile strength. Moreover, the incorporated NiPS particles could enhance the thermal stability of EP composites, showing the notably suppressed mass loss rate and added residual chars. This study provided a promising way for preparing the high-performance EP composites with organic-modified lamellar particles.

Electrical and thermal properties of epoxy composites filled with carbon nanotubes and inorganic particles

The electrical and thermal conductivity of the ternary epoxy composites (CMs) with two-component fillers, multiwall carbon nanotubes (MWCNT)/TiO2, and MWCNT/carbonyl iron (Fe) have been investigated. The increase of the percolation threshold was found for the ternary CMs compared to MWCNT/epoxy CMs. At MWCNT content higher than 3 wt.%, the conductivity of the ternary CMs is much higher than in MWCNT/epoxy. The temperature dependencies of the electrical resistivity were analyzed within the fluctuation-induced tunneling conductivity model. It was found that adding of two-component fillers MWCNT/TiO2 or MWCNT/Fe into epoxy promotes smaller changes in thermal conductivity compared to the two-phase MWCNT/epoxy composites.

Enhanced performance of rosin-based epoxy composites mixed with carbon nanotubes and cork powders from oriental oak bark

Rosin-based epoxy composites with high-impact toughness, tensile strength, modulus, and excellent flame retardance were prepared through a simple and effective approach. In this study, rosin-based epoxy resin (acrylopimaric diglycidyl ester, APA-ER) was synthesized from rosin, and the chemical structures of the products were determined by 1H NMR and FT-IR. The multiwalled carbon nanotubes (MWCNTs) and cork powders were introduced to the APA-ER to enhance the mechanical and thermal properties of epoxy composites. For the first time, cork powder was used to reinforce the modified rosin-based epoxy resin. Testing results of the mechanical properties indicated that the impact toughness of epoxy composite with 1.5 wt% MWCNTs and 3 wt% cork powders (100–200 mesh) had the highest value (12.34 and 12.04 kJ m−2), which was increased by 324% and 314%, respectively, compared to pure resin (2.91 kJ m−2). The composites with 1.5 wt% MWCNTs displayed better flexural and tensile performance compared to APA-ER/Cork. Moreover, the DMA, TG, and cone calorimeter results showed that APA-ER/Cork had a better performance in thermal stability and flame retardance than APA-ER/MWCNTs. Additionally, the flame retardance of rosin-based epoxy resin was further improved by adding MWCNTs and cork powder simultaneously. These results showed that the rosin-based epoxy resin could be toughened and strengthened effectively, and the thermal performance was improved by MWCNTs and cork powders. In conclusion, the value-added development of rosin and cork products was increased and applied in the field of functional materials.

Effect of Environmental Temperature on the Insulating Performance of Epoxy/MgO Nanocomposites

This article reports on the development of nano-MgO/epoxy resin composites with various mass ratios via a solution blending method. The influence of MgO nanofillers on the thermal properties and the effect of environmental temperature on the insulating properties of the composite material were analyzed. The results show that the thermal conductivity of the composites increased with an increasing MgO nanofiller content. Compared with the pure epoxy resin, the thermal conductivity increased by 75% when the content of MgO nanoparticles was 7%. The volume resistivity first increased and then decreased with an increasing doping concentration. The volume resistivity increased by 26.8% in comparison with the pure epoxy resin when the content of MgO nanoparticles was 1%, while its dielectric constant and dielectric loss increased with temperature. In addition, the dielectric constant increased and the dielectric loss first decreased and then increased with an increasing MgO nanoparticle content. Moreover, the MgO composites changed from a glassy to a rubbery state, and the breakdown strength was significantly reduced with an increased temperature. When the temperature was higher than the glass transition temperature, the breakdown strength decreased by 51.3% compared with the maximum breakdown strength at 20 °C. As the content of MgO nanoparticles increased, the breakdown strength of the composite first increased and then decreased. The highest breakdown strength was achieved when the content of MgO nanoparticles was 1%, which was 11.1% higher than that of the pure epoxy resin. It was concluded that the MgO nanofillers can significantly improve the thermal properties of epoxy composites and their insulation performance at high temperatures.

Evaluation of mechanical and thermal properties of epoxy composites reinforced with CaSiO3 particulate fillers

In the present numerical and experimental work, performance of epoxy composites with Wollastonite (CaSiO3) micro-particles that are systematically introduced into an epoxy matrix for reinforcement purposes is evaluated and presented. Magnetic stirrer is used to achieve homogeneous dispersion of the micro-particles into epoxy resin. The influence of CaSiO3 particles on hardness, flexural strength and impact strength was investigated. It is found that incorporation of CaSiO3 particles yield an effective improvement of the epoxy resin with a micro-particle content of 1–2 wt%. Composites reinforced with these particles showed increase in mechanical properties when compared to neat epoxy resin. Further, thermal behavior of both, neat and filler reinforced composites has been studied by Thermogravimetric analysis (TGA), to reveal the thermal stability of composites. In addition, mathematical models for hardness, flexural strength and impact strength are developed using Minitab 17 software. The developed models revealed high degree of correlation between experimental and predicted values.

Nanoscale thermal properties of carbon nanotubes/epoxy composites by atomistic simulations

Carbon nanotubes/epoxy composites are increasingly employed in several industrial fields, because of the enhanced material properties provided by the nanofillers. In particular, the thermal conductivity of these nanocomposites is determined by heat transfer mechanisms occurring over multiple scales, thus causing a complex relation between effective response and microscopic characteristics of the material. Here, the thermal properties of epoxy composites reinforced by carbon nanotubes are investigated using atomistic simulations. For a better understanding of how the effective thermal conductivity arises from the characteristics of the composite at the nanoscale, the thermal properties of its constituents are studied separately according to different geometrical, physical and chemical characteristics. The thermal conductivity of carbon nanotubes and epoxy resin alone is first investigated by molecular dynamics; then, the Kapitza resistance at the nanotube–nanotube and nanotube–epoxy interfaces is studied as well. The effective thermal conductivity of the carbon nanotubes/epoxy composite is finally computed and the observed behavior interpreted on the basis of the properties of the nanofillers, matrix and interfaces alone. Results – verified against effective medium theory predictions – show that, for the considered configurations, the effective thermal conductivity of the nanocomposite increases with the nanotube length and volume fraction, with the curing degree of the epoxy and system temperature. In perspective, the presented approach could be employed to investigate other constitutive materials or properties of nanocomposites.

Hybridization of hexagonal boron nitride nanosheets and multilayer graphene: Enhanced thermal properties of epoxy composites

We report an effective and reproducible method for hybridization of surface modified hexagonal boron nitride (h-BNNS) and multilayer graphene (MLG) by silane coupling agents. Simultaneously, silver (Ag) nanoparticles were grown on the interface of hybrid filler as a bridging agent during the hybridization process that activates free transportation of phonons when incorporated with epoxy matrix. Hybridization of surface modified h-BNNS and MLG improved the interfacial properties and the dispersion of the filler in the epoxy matrix. The hybrid filler BNNS-Ag-MLG (H-BSG) incorporated in the epoxy matrix and characterized for thermal properties. The thermal analysis confirmed that exceptionally improved thermal conductive and excellent thermally stable epoxy composite was fabricated. It was found that ~26 folds improvement in in-plane thermal conductivity was recorded by addition of 10 wt % of H-BSG in comparison with neat epoxy. This study indicates a step towards developing a strong interfacial connection between MLG and h-BNNS to make effective hybrid filler and emerging candidate for thermal interface applications.