Epoxy Nanocomposites Research Articles

Charge Transport Characteristics of Core-Shell SiC Filled Epoxy Nanocomposites

Charge Transport Characteristics of Core-Shell SiC Filled Epoxy Nanocomposites

Radiation Stability of Epoxy Nanocomposites with Titanium(IV) Dioxide Nanoparticles

Radiation Stability of Epoxy Nanocomposites with Titanium(IV) Dioxide Nanoparticles

Synthesis of highly grafted MWCNTs with epoxy silane to improve curing, thermal and mechanical performances of epoxy nanocomposites

Hydrophobic CNTs have weak interfacial interactions to epoxy matrix which causes their agglomeration and significant decline in the thermal/electrical/mechanical of epoxy nanocomposites. In this research, multi walled carbon nanotubes (MWCNTs) were acid treated at three different times to prepare nanotubes with the highest functional groups on surface. Thereafter, the best functionalized nanotubes were surface modified using 3-glycidyloxypropyltriethoxysilane (GPTES) at different concentrations to prepare GPTES@MWCNTs nanoparticles with the highest silane grafting content. The unmodified, acid treated and GPTES@MWCNTs were characterized carefully. The pure, functionalized and silane modified nanotubes were then applied to epoxy resin at 0.5 to 2 wt% and the mechanical, curing, thermo-mechanical and morphological features of the nanocomposites were assessed. It was declared that the unmodified MWCNTs (at 0.5 wt%) caused about 35 % decline in enthalpy of curing and 24 °C decrement in decomposition temperature of the epoxy polymer. However, the modified nanotubes enhanced the curing enthalpy and decomposition temperature of the polymer by 95 % and 31 °C compared to the unmodified nanocomposites, respectively. It was also found that the GPTES@MWCNT containing nanocomposite (at 0.5 wt%) showed enhanced tensile, flexural and compressive strengths by 69, 106 and 34 % compared to the pristine epoxy sample and 47, 73 and 25 % compared to the unmodified nanocomposite, respectively. It also caused 54 % and 13 °C improvement in the storage modulus and Tg compared to the unmodified nanocomposite.

Electrical characteristics of different concentration of silica nanoparticles embedded in epoxy resin

In this study, modified epoxy nanocomposite was produced by incorporating SiO2 nanoparticles of 15–30 nm in size, with different concentrations ranging from 1 to 20 wt%. The electrical properties of the epoxy nanocomposite were measured at room temperature in the frequency range of 10−2–107 Hz. To determine the impact of nanoparticles on the epoxy composition, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS), Fourier transform infrared spectra (FTIR) spectroscopy, and Raman spectroscopy were conducted. With an increase in filler (SiO2 nanoparticles) content, the electrical characteristics of the epoxy nanocomposite exhibited multiple changes. At low concentrations, all electrical properties experienced a notable increase. The epoxy with 15 wt% of SiO2 nanoparticles samples had a lower permittivity, loss number, conductivity, and capacitance than the unfilled epoxy. At medium concentrations (5 to 15 wt%), the formation of immobilized nanolayers has an impact on permittivity, loss number, conductivity, and capacitance, which have decreased; impedance and modulus increased. The initiation of contact between the nanofillers at a concentration of 20 wt% leads to the formation of continuous interfacial conductive pathways, resulting in a dramatic increase in the permittivity, conductivity, and capacitance of the composites, while concurrently reducing impedance.

Polydopamine functionalised ceria-zirconia nanoparticles embedded water-borne epoxy nanocomposite for anti-biofouling coatings

Biofouling, the accumulation of microorganisms, plants, algae on wet surfaces is one of the major issues adversely affecting the overall hydrodynamic performance of the marine vessels. Ceria (CeO2) nanoparticles (NPs) are effectively used as anti-biofouling agent to prevent the deterioration of steel structures, due to their excellent redox capacity. Various approaches are being investigated to enhance the antifouling activity of ceria NPs. Here, we report the development of novel polydopamine (PDA) functionalised ceria-zirconia nanoparticles filled water-borne epoxy nanocomposite coating to prevent the microbial-induced corrosion of mild steel. Ceria NPs were functionalised with PDA to enhance the dispersibility and improve their ability to resist biofouling in water-borne epoxy resin coatings against microbial species. As the anti-biofouling activity of ceria depends on their oxygen storage capacity, zirconium was incorporated to create a defective crystal structure with more active oxygen storage and release sites. Ceria and ceria-zirconia NPs were synthesised by precipitation method and functionalised with PDA. The functionalisation of ceria-zirconia (CZ) NPs was confirmed by Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Confocal Raman spectroscopy and X-ray Photon spectroscopy (XPS). Thermogravimetric analysis (TGA) shows that incorporation of zirconium increases the amount of oxygen vacancies in the crystal lattice there by enhancing ceria's redox potential. Anti-biofouling and anti-biocorrosion properties of the coatings were explored against different microbial strains. The antibacterial tests show that colony-forming units (CFU) of PDA functionalized ceria-zirconia epoxy (EPCZ) nanocomposites were suppressed by 93 % and 87 % in the case of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) bacteria, respectively. Biofilm inhibition studies show that EPCZ nanocomposite coatings have higher biofilm inhibition efficiency against gram-negative bacteria (96.37 %) than gram-positive bacteria (62.67 %) due to the differences in their morphology. The practical applicability of the nanocomposite coatings was studied using cultured seawater consortia, and the results reveal that PCZ nanoparticles provide superior biofilm inhibition. Electrochemical impedance spectroscopy (EIS) reveals that the EPCZ coatings exhibit significant enhancement in charge transfer resistance and coating resistance. The synergistic effect of PDA functionalisation and zirconium incorporation in ceria leads to the exceptional biocorrosion resistance in corrosive bacterial environments.

Evaluation of Thermal and Mechanical Properties of Epoxy Resin/Aluminum Nanoparticle Composites

Abstract: In this study, we explored the development of epoxy resin nanocomposites with 0.1, 0.3%, and 1.0% by weight of aluminum nanoparticles. These nanocomposites were evaluated for mechanical properties (tensile test and Izod strength test) and thermal properties (differential scanning calorimetry and thermogravimetric analyses), and their morphology was assessed using field emission gun scanning electron microscopy. Adding even small amounts of aluminum nanoparticles led to notable improvements in the mechanical and thermal resistance. Remarkably, composites with 1.0 wt% of aluminum nanoparticles presented a 25% increase in the elastic modulus, a 20 °C increase in the glass transition temperature, and a 30 °C increase in the degradation temperature. These findings hold significant promise for advancing the field of polymer-metal nanocomposites.

Enhancement mechanism of epoxy resin by polyacrylic acid-modified 3D porous graphene: A microscopic and molecular dynamics perspective

Graphene is a two-dimensional nanomaterial with remarkable strength and is a highly effective enhancer in polymer materials. However, the mechanisms underlying the enhancement between the enhancer and the base material remain uncertain. In this study, we have successfully prepared advanced epoxy nanocomposites by grafting polyacrylic acid onto 3D porous graphene (3DG). The covalent functionalization of 3DG has proven to be highly effective in preventing its aggregation within the epoxy matrix. The mechanical test results demonstrated a substantial enhancement in the tensile strength (41.04%), elastic modulus (43.23%), and impact strength (370.88%) of the epoxy resin upon the incorporation of polyacrylic acid-modified graphene (PAAMG). The fracture surfaces of the composites were examined using scanning electron microscopy, which provided insights into the enhancer's mechanism of enhancement. Notably, employing a range of molecular dynamic simulations and analyses, we found that PAAMG exhibits the ability to bifurcate cracks, thereby improving the mechanical properties of the material.

Impact of water diffusion on electrical properties of epoxy nanocomposites

This study investigates the effects of water ageing at 80 °C on glass fibre hybrid epoxy nanocomposites with multi-walled carbon nanotubes and graphene nanoplatelets. Effect of water uptake in the epoxy matrix is mitigated by the inclusion of carbon nanofillers, leading to improved hydrophobic nature. A comparative study is performed on the water uptake of the epoxy-amine matrix cured with aliphatic amine, with 0.4 weight percent of MWCNT and 0.6 weight percent of graphene nanoplatelets (GNPs). Gravimetric assessment and electrical impedance measurements are carried out over a period of 3000 h to assess water diffusion coefficients and water saturation. Water absorption is measured until saturation, and results show that the water diffusion coefficient of the hybrid nanocomposites is increased from 2.51 × 10−8 (m2 s−1) at 27 °C to 3.32 × 10−8 (m2 s−1) at 80 °C and it is higher than that of the base epoxy composites. Cole–Cole diagrams have revealed heterogeneity of the composites studied. Water diffusion results in the plasticization of the matrix, and it manifests in the broadening of the tanδ peak observed in water-aged epoxy composites. With the inclusion of hybrid MWCNT and GNP nanofillers.,the water diffusion coefficient is reduced to half, and saturation is increased by four times.

The Influence of Pristine and Aminoacetic Acid-Treated Aluminum Nitride on the Structure, Curing Processes, and Properties of Epoxy Nanocomposites

This article describes the preparation of aluminum nitride (AlN) functionalized with amino groups by chemically modifying the surface of AlN with aminoacetic acid and their dispersion in the epoxy composition. As a result of the studies, it was found that the functionalization of AlN particles with aminoacetic acid ensured their better chemical compatibility with the epoxy composition, which facilitated the dispersibility of AlN particles; it was also found that the functionalization of the nanofiller has a significant effect on the structure, curing kinetics, physicochemical and mechanical properties of epoxy nanocomposites. The optimal concentration of the functionalizing agent (aminoacetic acid) has been determined, which is necessary for the chemical binding of the functional groups of aminoacetic acid, the epoxy oligomer and AlN, which best affects the dispersion and the size distribution of AlN particles, and also ensures maximum strength characteristics of epoxy composites containing AlN treated with aminoacetic acid: bending stress and bending modulus increase by 35% and 80%, respectively, while tensile strength and tensile elastic modulus increase by 74% and 36%, respectively. Furthermore, the impact strength shows a remarkable boost of 133% compared to plasticized epoxy composite without AlN.

Mechanical and environmental performances of an epoxy-resin-based recycled artificial stone containing hazardous sediment

Solidifying and stabilizing hazardous sediment from petrochemical activities are not only expensive but make also high-volume waste to landfills. Parallel, finding alternative aggregates with lower costs can reduce the capital cost of artificial stone. For the first time, a combination of hazardous sediments and stone waste was used as aggregates to produce the recycled artificial stones. Furthermore, the target of this study is to evaluate the behavior of these recycled artificial stones under external forces and weathering, as well as in the acid environment. In order to evaluate the properties of the stones containing hazardous sediment, the compressive strength, the brightness variation, and water absorption under UV radiation, 60 cycles of salt attack, 60 cycles of freezing and thawing, and 60 cycles of thermal shock cycles were evaluated. In order to assess the leaching of heavy metals, according to the US toxicity characteristic leaching procedure (TCLP) and DIN38414-S4, two leaching tests were used to evaluate the leaching of the heavy metals under rainfall and acid environment, like soil. In order to conduct leaching tests, three spices from the crushed zone of the stone under compressive test were used. The results show that the stones have suitable performance in comparison to the performance of the artificial stone containing nonhazardous sand, travertine stone, and treated travertine stone using epoxy resin and nanocomposite. Based on the results, P90HSa10Eb25T25, with 39.3 MPa compressive strength, 3.02 color variation under 60 cycles of salt attack, and 1.59 color variation under UV radiation, has the best performance among the recycled artificial stones.

An insight into the effect of carbon nanofillers in glass fibre epoxy nanocomposites through dielectric spectroscopy

Interfacial characteristics of nanocomposites are critical limiting factors in the design of polymer nanocomposites. The nanocomposites have complex structures and play a pivotal role in controlling functional properties. Analysis of interfacial layers in polymer nanocomposites, existing between the polymer matrix and the nanoparticles plays a major role in determining their characteristics. High-frequency analysis of electrical conductivity and dielectric properties of carbon nanofillers which are embedded in an epoxy matrix were analysed using alternating current dielectric spectra. This article provides a correlation between the electrical transport properties and dielectric behaviour of epoxy carbon nanocomposites at different temperatures are investigated with variations in frequency. Electrical transport properties of nanocomposites are primarily dictated by electron tunnelling and matrix, nanofillers conductivity. Dielectric spectroscopy in the frequency range 10 Hz–8 MHz has been performed on epoxy nanocomposites with and without hybrid carbon nanofillers at one weight percentage (2:3 ratio). Dominant dielectric relaxation mode is observed in the base composite at a low-frequency region (≥10 Hz), whereas nanocomposite with hybrid carbon nanofillers is observed to induce two dielectric relaxations in the kHz region. Increase in non-monotonic variations in dielectric spectra makes the nanocomposite suitable for high temperature low sag conductor core, aerospace and cryogenic engineering applications.

Thermal, mechanical, thermo‐mechanical and morphological properties of graphene nanoplatelets reinforced green epoxy nanocomposites

AbstractThe efficient inclusion of GNPs (graphene nanoplatelets) as an effective nano‐fillers for green polymer matrices produced with 28% of carbon originating from biomass tends to significantly improve mechanical and thermal properties. In the present work, green epoxy nanocomposites with low loading of (0.1, 0.25, and 0.5) wt% of the GNPs were made using a solution blending technique using acetone as the solvent. In mechanical stirring, the ultrasonic bath was used to ensure the efficient dispersion of GNPs within green epoxy. The resulting nanocomposites were comprehensively characterized and compared to unfilled green epoxy. Different tools were used to appraise morphological, thermal, thermo‐mechanical, and mechanical behavior. The results confirmed through FE‐SEM showed an optimal dispersion of GNPs with nanocomposites. The thermal degradation temperature (Td) of GNPs curve with 0.25 wt% loading was shifted toward higher temperature (from 336°C to 342°C) due to low percentage of loading of GNPs which showed an enhance thermal stability of polymer matrix with 0.25 wt% loading. The mechanical results were also in lined with previously published literature, in the tensile test 6.45% and hardness 13.3% increment was achieved. Overall, the results underscored significant improvements in green nanocomposite performance with low wt% of GNPs.Highlights The study focuses on development and characterization of green epoxy nanocomposites, which utilize environmentally friendly materials as a matrix, highlighting the significance of sustainability. The study explores effects of low loading of GNPs in green epoxy nanocomposites. The results demonstrate significant improvements in mechanical and thermal properties with optimized presence of GNPs. This investigation provides insights into optimal amount of GNPs required to achieve improved properties. Research evaluates multifaceted analysis provides a holistic understanding of performance enhancements achieved through inclusion of GNPs.

Effect of sampling orientation on the mechanical properties of glass fiber reinforced epoxy nanocomposites

Fiber-reinforced polymer composites are manufactured using various methods, with vacuum-assisted resin transfer molding (VARTM or VARIM) being a notable technique under extensive scrutiny. This study's primary focus lies in assessing how the orientation of sampling impacts the mechanical properties of both pure and nano-composite materials. 2 wt.% nano Al2O3-doped and non-doped composites were produced using the VARTM process. Tensile, flexural, and density test specimens were extracted from three distinct zones: those aligned horizontally to the resin flow (HRF) and those oriented vertically to the resin flow (VRF). Remarkably, experimental results revealed that values obtained from samples in the third zone, specifically on the vacuum outlet side, were up to 3.91% higher when compared to the others. Notably, VRF samples consistently outperformed their HRF counterparts. To determine whether these results held statistical significance, a one-way ANOVA analysis was conducted. Although the results didn't show any significant statistical differences, it's still crucial to be careful about how you select the sample orientation in experimental studies. To enable a more precise comparison of stress values across various plates, it is important to extract samples with uniform orientation and from consistent zones.

Reprocessing and reconfigurable shape recovery of epoxy and Fe3O4 nanocomposites enabled by crosslinking with a polymeric hardener bearing disulfide bonds

In this contribution, we reported the preparation of the nanocomposites of epoxy with Fe3O4 with poly(α-lipoic acid) (PLA) as a polymeric crosslinker. It was found that the surface reaction between Fe3O4 nanoparticles and the macromolecular crosslinker significantly facilitated the fine dispersion of the inorganic nanoparticles. In the meantime, dynamic disulfide bonds were successfully introduced into the nanocomposites. Therefore, the nanocomposites displayed the excellent reprocessing (recycling) properties. In addition, the nanocomposites had the shape memory properties; the original shapes of the shape memory nanocomposites can be reprogrammed via the exchange of dynamic disulfide bonds. Owing to the incorporation of Fe3O4 nanoparticles, the nanocomposites possessed the excellent paramagnetic and photothermal properties. Furthermore, the photothermal properties can be utilized to trigger the shape recovery in a non-contact fashion.

High-performance epoxy nanocomposites via constructing a rigid-flexible interface with graphene oxide functionalized by polyetheramine and f-SiO2

Graphene oxide (GO) is an ideal reinforcement for improving mechanical properties of epoxy (EP) and reducing its coefficient of thermal expansion (CTE). However, the poor interfacial interaction between GO and polymer matrix seriously hinders the reinforcing effect of GO. To improve their interface, we first functionalized GO with flexible polyetheramine (PEA) and f-SiO2 rigid nanoparticles, obtaining PEA-GO and SiO2-PEA-GO hybrids, respectively. Then the PEA-GO and SiO2-PEA-GO were incorporated into EP to obtain nanocomposites with flexible interphases and rigid-flexible interphases, respectively. The interfaces were tuned by two PEA molecules (D230 and D2000) with different chain lengths. The effects of the different interface structures on the mechanical properties and CTE of the GO/EP nanocomposites with a 0.25 wt% filler loading were investigated. It was found that the effects of SiO2-PEA-GO on strengthening and toughening EP matrix and on reducing its CTE were much better than those of PEA-GO, because the rigid-flexible interfaces provided higher bonding strength and better energy dissipation mechanisms than the flexible interfaces. Moreover, the D230-GO/EP nanocomposite containing shorter PEA (D230) molecules exhibited higher strength but lower toughness and CTE than the D2000-GO/EP nanocomposite. However, the SiO2-D2000-GO/EP nanocomposite showed greater strength, toughness and CTE than the SiO2-D230-GO/EP nanocomposite. This indicated that the longer PEA molecules in rigid-flexible interphases produced higher improvement in strength and toughness but smaller decreases in CTE. This work provides a promising strategy of constructing an adjustable flexible-rigid interfacial structure and opens an avenue for developing GO/EP nanocomposites with high mechanical properties and low CTE.

Sustained electromagnetic parameters of barium ferrite and epoxy nanocomposites for patch antenna miniaturization over GHz frequency range

Herein, we synthesized BaFe12O19 and BaFe12O19: Epoxy (50:50) nanocomposite using the co-precipitation method. X-ray Diffraction (XRD) pattern confirmed the formation of hexagonal structure where the crystallite size is 27.3 nm. The Field Emission Scanning Electron Microscopy (FESEM) showed the formation of hexagonal grains and Energy Dispersive X-ray Spectroscopy (EDX) confirmed the purity of the sample. Transmission Electron Microscopy (TEM) showed the crystallite size of 34 ± 2 nm for BaF nanoparticles and 42 ± 2 nm for Ba-Epoxy nano composites. The values of ε′ is found within the range of 6.2–6 for BaF and 4.5–4 for BaF: Epoxy over the whole frequency range. In addition, the value of real part of permeability μ′ are 1.9–1.2 and 1.4–1 for BaF and BaF: Epoxy, respectively. The ac conductivity is observed to remain constant till 0.6×109 Hz and 0.2×109 Hz frequency for BaF and BaF: Epoxy, respectively.

Model Approach to Thermal Conductivity in Hybrid Graphene-Polymer Nanocomposites.

The thermal conductivity of epoxy nanocomposites filled with self-assembled hybrid nanoparticles composed of multilayered graphene nanoplatelets and anatase nanoparticles was described using an analytical model based on the effective medium approximation with a reasonable amount of input data. The proposed effective thickness approach allowed for the simplification of the thermal conductivity simulations in hybrid graphene@anatase TiO2 nanosheets by including the phenomenological thermal boundary resistance. The sensitivity of the modeled thermal conductivity to the geometrical and material parameters of filling particles and the host polymer matrix, filler's mass concentration, self-assembling degree, and Kapitza thermal boundary resistances at emerging interfaces was numerically evaluated. A fair agreement of the calculated and measured room-temperature thermal conductivity was obtained.

Evolution of phase structure and fracture toughness induced by carbon nanotubes in thermoplastic-toughened epoxy nanocomposites

The nanomaterials-filled thermoset/thermoplastic ternary nanocomposites exhibit important potential to achieve both toughening and stiffening effect for thermosetting resin. However, the targeted growth in fracture toughness and the synergistic toughening mechanism of thermoplastic resin and nanomaterials has not been attained due to the complex immiscible ternary system. In this work, thermoplastic resin polyetherketone-cardo (PEK-C) and carbon nanotubes (CNTs) were synergistically incorporated in thermosetting epoxy (EP) resin. The structure-property correlation was explored via the investigation of mechanical performance and microstructure. The results showed that the change of fracture toughness was not linearly related to the PEK-C content, while closely related to the dualphase structure formed by EP and PEK-C. After introducing CNTs, the CNTs were selectively located in the continuous phase of EP, which increased the viscosity of the located region and hindered the coarsening and interconnecting of the dispersed phase of PEK-C, weakening the toughening effect of dualphase structure.

Ferroelectric, dielectric, and EMI attenuation characteristics of BaFe2O4/MWCNTs/epoxy nanocomposites

ABSTRACT This study reports the synthesis of barium-ferrite (BaFe2O4) particles by co-precipitation method, which is employed to prepare BaFe2O4/multiwall carbon nanotubes (MWCNTs)/epoxy nanocomposites. Furthermore, the structural properties, ferroelectric and dielectric properties, and electromagnetic attenuation properties are studied. The role of varying concentrations of BaFe2O4, frequency, and temperature on dielectric behavior is studied. In the presence of applied field, dielectric constant enhances as a result of interfacial polarization with increasing BaFe2O4 concentration. The permittivity is highest at low frequency and decreased with increasing frequency. With temperature, initially, dielectric constant increases and then decreases as a result of charge accumulation at interfaces and leads to interfacial polarization as confirmed by ferroelectric behavior. Here, BaFe2O4/MWCNTs/epoxy composite (with 40 phr BFO, where phr denotes parts per hundred) exhibited the highest value of saturation polarization (PS) ~0.31 µC/cm2 and low value of remanent polarization (Pr), that is ~0.009 µC/cm2. Moreover, composites exhibited high electromagnetic interference (EMI) shielding effectiveness (SE) of nearly 19 dB for 40 phr BaFe2O4 concentration at 11.3 GHz. Here, the reflection-dominated SE is ~1.06 dB and absorption-dominated SE is about 18.67 dB, which dominates the total SE. The absorption-dominant behavior is depicted by the BaFe2O4/MWCNTs/epoxy nanocomposites in EMI shielding as further conferred in the text.

Hierarchical MXene@PBA nanohybrids towards high-efficiency flame retardancy and smoke suppression of robust yet tough polymer nanocomposites at ultra-low additions

Developing efficient flame-retardant MXene-based polymeric materials with enhanced mechanical properties has been a huge challenge. Herein, Prussian blue analogues (PBAs) were used to modify the surface of MXene nanosheets via an electrostatic self-assembly method to construct hierarchical MXene-based nanohybrids (MXene@PBA). Then, MXene@PBA was incorporated into the epoxy matrix to fabricate high-performance epoxy nanocomposites (EP-MXene@PBA). The study indicates that hierarchical MXene@PBA exhibits excellent dispersion performance in the epoxy matrix. Notably, MXene@PBA results in high-efficiency flame retardancy and smoke suppression for epoxy nanocomposites at ultra-low additions. What is very surprising is that only 1.0 wt% MXene@PBA can easily enhance the UL-94 rating of EP-1.0%MXene@PBA to V0. Meanwhile, the peak heat release rate (pHRR), total smoke production (TSP), and peak CO production rate (pCO) are remarkably reduced by 36.70%, 34.28%, and 43.48%, compared to those of the pristine epoxy resin, respectively. Furthermore, the 1.0 wt% MXene@PBA nanohybrids can enhance the flexural and impact strengths of EP-1.0%MXene@PBA. This work provides a feasible strategy for the creation of multifunctional MXene derivatives and their polymeric nanocomposites and holds great promise for many industrial applications.