Preparation Of Nanocomposites Research Articles

Damping and acoustic properties of nanosilica filled poly(styrene-acrylate) interpenetrating polymer networks (IPNs): Effect of nanocomposite preparation method

Research on noise pollution reduction has focused on utilizing damping coatings and polymer nanocomposites to enhance sound absorption. Nanosilica/poly(styrene-acrylate) nanocomposites as a water-based coating were prepared through in-situ emulsion polymerization and direct mixing methods at varying concentrations of 1, 2, and 3 wt% of nanosilica. Fourier transform infrared (FTIR) spectroscopy revealed that the inclusion of surfactant-containing micelles and a more extended synthesis period in the in-situ synthesis technique enhanced the interaction between silica nanoparticles and polymer chains. Dynamic light scattering (DLS) analysis showed a unimodal distribution and an acceptable range of polydispersity index (PDI) for neat and nanocomposite latexes. The addition of silica nanoparticles enhanced the stability of latex particles, especially evident in the direct mixing method. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the better dispersion of nanoparticles within the polymer matrix in the in-situ method. The addition of nanosilica resulted in a significant increase in pseudoplastic behavior and viscosity, notably in the in-situ synthesis. In both the in-situ synthesis and direct mixing techniques, the addition of 1 wt% of nanosilica resulted in an increase in the damping factor of nanocomposite films to about 2. However, when the nanosilica content was further increased to 3 wt%, the damping factor decreased. Acoustic tests demonstrated improved sound absorption with silica nanoparticles, yielding noise reduction coefficient (NRC) values of 0.49 and 0.46 for in-situ synthesis and direct mixing. The direct mixing method notably enhanced tensile properties at all nanoparticle content levels. Dried nanocomposite films exhibited superior UV-blocking capabilities compared to neat polymer films.

Gamma irradiation green synthesis of (polyacrylamide/chitosan/silver nanoparticles) hydrogel nanocomposites and their using as antifungal against Candida albicans and anti-cancer modulator

Silver nanoparticles-loaded hydrogel nanocomposites are exploited for medicinal and pharmaceutical applications. Hydrogel nanocomposites were prepared from acrylamide (Am), chitosan (CS) and AgNO3 utilizing gamma rays. Diverse variables were applied in preparation of silver nanoparticles-laoded hydrogel nanocomposites of (PAm/CS)-AgNPs such as influence of radiation dose and influnece of CS concentration. Diverse techniques were utilized to characterize hydrogel nanocomposites; Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and scanning electron microscopy (SEM). Results confirmed formation of silver nanoparticles-loaded hydrogel nanocomposites of (PAm/CS)-AgNPs. Antifungal activity of (PAm/CS)-AgNPs hydrogel nanocomposites on viability of C. albicans was esitmated. Results displayed the efficient microbial inhibition activity of treatment against C. albicans compared to control. Furthermore, (PAm/CS)-AgNPs hydrogel nanocomposite against cervical cancer HeLa cell line was investigated. Cytotoxicity of (PAm/CS)-AgNPs hydrogel nanocomposites on prior cancer cell line empolyed to prohibition of cell growth assesssed by MTT test. HeLa cancer cell is treated by (PAm/CS)-AgNPs for 48 h exposed a potential apoptotic activity by noticeable up-regulation of p53 gene expression. Moreover, anticancer activity was investigated by down-regulation of platelet-based growth variable receptor beta (PDGFR-β), Bcl2, Cathepsine, and MMP-2 gene expression. antioxidant activity was investigated and results showed antioxidant activity of (PAm/CS) hydrogel and (PAm/CS)-AgNPs hydrogel nanocomposite are 87.8% and 62.9%, respectively.

Flocculation potential regulation to achieve the improved thermal‐mechanical performance for CB/GO reinforced NR nanocomposites

AbstractWith the rapid development of modern transportation systems, optimizing the relationship between structure and performance to obtain natural rubber‐based nanocomposites with excellent comprehensive performance is still worth to investigation. Herein, the regulation of flocculation potential through different flocculants selection on the thermomechanical properties for carbon black/graphene oxide reinforced natural rubber (CB/GO/NR) nanocomposites were investigated based on the compression electric double layer theory. The results showed that formic acid owned the highest zeta potential with comparison of sodium chloride (NaCl), calcium chloride (CaCl2), and aluminum chloride (AlCl3). Meanwhile, as the content was 8 wt%, tensile strength, tearing strength and thermal conductivity could achieve to 27.64 MPa, 56.89 N/mm, and 1.05 W m−1 K−1, respectively. While the heat generation after compression fatigue dropped to 10.1°C. These findings reveal that the highest zeta potential of formic acid could promote the improvement of flocculation degree between GO and NR latex and significantly enhanced the thermomechanical properties of CB/GO/NR nanocomposites due to the larger flocculation potential difference. Therefore, this study not only provides important theoretical insights for preparing high‐performance NR‐based nanocomposites, but also highlights the crucial role of high zeta potential flocculants in optimizing the composite performance. More importantly, the findings offer the creative insights for preparation of the excellent comprehensive NR nanocomposites for the practical industry application.Highlights The effect of flocculation degree on the properties of CB/GO/NR composites was studied. Formic acid was benefit to the flocculation and could promote the surface interaction. CB/GO/NR composites possessed the improved thermal and mechanical properties.

Preparation and Characterization of Tensile Properties of PMMA/SiC Nanowhiskers Nanocomposite Films: Effect of Filler Loading and Silane Treatment

The preparation of nanocomposites through melt mixing was challenging as the nanofillers tend to form agglomeration. The silicon carbide nanowhiskers (SiCNWs) filled poly (methyl methacrylate) (PMMA) thin film in this study was prepared by means of solution casting. Acetone with low toxicity was used as solvent to dissolve the PMMA pellets. A coupling agent, silane was used to enhance the properties of composite films. Besides, the untreated and treated SiCNWs were filled into PMMA matrix, respectively with the filler loading varied from 0.2 to 0.8 wt%. The universal testing machine was used to investigate the tensile properties of composites. It was found out that the tensile strength of the PMMA was reduced in the presence of SiCNWs. However, the tensile strength had increased with the rise of filler loading. At 0.8 wt% of SiCNWs, the composites’ tensile strength was comparable to virgin PMMA. Meanwhile, the SiCNWs had reduced the elongation at break but increased the elastic modulus of PMMA/SiCNWs nanocomposite films. In addition, silane surface treatment on SiCNWs had improved the tensile strength and ductility but lowered the elastic modulus of the nanocomposites. The improvement was due to the enhancement of interfacial adhesion between SiCNWs and PMMA.

Gas sensing properties of Ti0.2V1.8CTx/V2O5 nanocomposite

A method for the preparation of nanocomposite containing Ti0.2V1.8CTx MXene core and titanium-doped vanadium oxide surface layers as a result of relatively low-temperature partial oxidation of MXene multilayer - two-dimensional vanadium-titanium carbide has been developed. It is shown that during oxidation in air atmosphere of initial Ti0.2V1.8CTx at temperature 250°С, in general, the microstructure of accordion-like aggregates with some increase in porosity of their constituent layers and increase in their thickness due to the formation of V2O5 is preserved. At the same time, preservation of the MXene structure with a decrease in the interplanar spacing from 10.3 (initial powder Ti0.2V1.8CTx) to 7.3 Å was observed. Raman spectroscopy confirmed the formation of vanadium oxide. Kelvin-probe force microscopy data revealed that the formation of Ti0.2V1.8CTx/V2O5 nanocomposite results in a decrease in the work function from 4.88 (Ti0.2V1.8CTx) to 4.68 eV. The chemosensor properties towards a range of gaseous analytes (H2, CO, NH3, NO2, C6H6, C3H6O, CH4, C2H5OH and O2) have been comprehensively studied for Ti0.2V1.8CTx/V2O5 layers coated using the microplotter printing. At increased detection temperatures (125–200°С), high sensitivity to oxygen (10% O2) and NO2 (100 ppm) is observed; there are notable responses to humidity (50% RH) throughout the 25–200°С temperature range. At room temperature, good response to acetone, ethanol and ammonia is observed.

Preparation and characterization of copper oxide-chitosan nanocomposite for colon-targeted drug delivery system

Preparation and characterization of copper oxide-chitosan nanocomposite for colon-targeted drug delivery system

Numerical simulation of fluid flow characteristics and ultrasonic cavitation performance in novel-designed stirred tank sonoreactor

A novel-designed stirred tank sonoreactor was developed to well solve large-scale dispersion of nanoparticles in liquid phase system. The fluid flow characteristics and ultrasonic cavitation performance in the sonoreactor were numerically simulated by CFD method. By comparing the pressure, cavitation bubble and velocity distribution under different situations, it is found that larger ultrasonic amplitude, relatively smaller ultrasonic frequency, higher saturated vapor pressure and lower viscosity of liquid medium are beneficial to ultrasonic cavitation. Besides, the acoustic flow action is strengthened with the increase of ultrasonic frequency and decrease of gas-liquid mixture's average density. For the designed sonoreactor, it is critical that high-frequency transducers should be determined near the bottom and upper region of the kettle, and large-amplitude transducers can be confirmed in the middle position. The research findings will provide theoretical and technical supports for developing state-of-the-art sonoreactors and optimizing ultrasonic process parameters in the industrialized preparation of nanocomposites.

Ultrasound-assisted freeze-drying graphitization process for the fabrication of two-dimensional carbon/Fe3O4 composite aerogels for microwave absorption

Magnetic Fe3O4 materials have received attention from researchers due to their significant wave absorption potential, but there are limitations to their efficient electromagnetic wave absorption and lightweight applications. Combining materials with dielectric properties to optimize the performance of Fe3O4 has become one of the research directions. In particular, carbon nanomaterials, such as graphene, show great application prospects in the field of microwave absorption due to their physical properties. To improve the impedance mismatch issue of graphene, researchers consider combining it with magnetic nanoparticles. Commercial applications require materials that are cost-effective, easy to produce, and environmentally sustainable, driving research on novel 2D carbon materials. In this study, 2D carbon materials were prepared by ultrasound-assisted freeze-drying/graphitization process using polymers as precursors, which simplifies the preparation process and avoids the use of expensive sacrificial templates and catalysts. The 2D carbon materials prepared by this method were used as the dielectric component in the wave-absorbing composites, and the nano effect was utilized to significantly improve the microwave absorption properties of the materials. The maximum reflection loss of the prepared graphite nano-aerogel reaches −84.16 dB and the EAB reaches 3.74 GHz. In addition, by adding Fe3O4 nanoparticles and applying an ultrasonic field for dispersion in the freeze-drying process, the nanoparticle agglomeration is effectively prevented, which provides a simple and efficient pathway for the preparation of nanocomposites.

Influence of silane and polyethylene glycol functionalization of boron nitride nanosheets on mechanical and thermal properties of epoxy nanocomposites: Machine and deep learning forecasting

AbstractThe influence of hexagonal boron nitride (hBN) nanosheet surface modification on epoxy nanocomposites' mechanical and thermal properties were investigated. An innovative approach was developed for synthesizing hBN nanosheets (hBNNs) via optimized ultrasonic‐assisted liquid‐phase exfoliation (UALPE), followed by functionalization with 3‐aminopropyltriethoxysilane (APTS) and polyethylene glycol (PEG600) for nanocomposite preparation. Compared to unmodified epoxy, nanocomposites containing 0.3 wt% of pristine hBNNs exhibited significant enhancements in flexural strength (125.28 MPa) and tensile strength (53.35 MPa), with respective increases of 40.57% and 43.23%. PEG‐hBNNs improved flexural and tensile strengths to 136.83 and 58.57 MPa, respectively. The most substantial enhancements were observed with APTS‐hBNNs, yielding flexural and tensile strengths of 174.13 and 63.53 MPa, reflecting increases of 95.37% and 70.50%, attributed to better interfacial interactions and a more effective crack deflection mechanism. Thermal stability analyses revealed superior performance of modified hBNNs epoxy nanocomposites, increasing 8.2°C and 6.3°C at 50 wt% degradation as compared to the unmodified system, owing to enhanced physical barrier properties. Structural and morphological analyses validated the successful exfoliation and modification of hBNNs. Predictive models utilizing machine and deep learning (DL) techniques, particularly DL with the adaptive moment estimation (ADAM) optimizer, effectively forecasted mechanical properties, achieving high R2 values.HIGHLIGHTS 0.3 wt% modified hBNNs epoxy nanocomposite showed the highest mechanical strength Improved thermal stability of epoxy nanocomposite by modification of hBNNs Improved crack deflection mechanism in the presence of surface‐modified hBNNs Deep learning with ADAM optimizer showed high R2 and low prediction loss

Preparation and characterization of chitosan graphene oxide nanocomposite for the removal of 17-β-estradiol sulfate from water: kinetics, thermodynamics and simulation studies

The presence of 17-β-estradiol sulfate residue in water is of great concern due to its hazardous nature (endocrine disruptor and carcinogen). For this, chitosan was used with graphene oxide to prepare chitosan graphene oxide nanocomposite. This material was characterized and used as an adsorbent for the removal of 17-β-estradiol sulfate residue in water. This adsorbent showed a rapid, efficient, and environmentally friendly method of 17-β-estradiol sulfate removal from water. The optimal conditions for maximum removal were 93.6% (4.68 mg/g) with 2500 µg/L of 17-β-estradiol sulfate, 30 min of agitation, 0.50 g/L of graphene oxide chitosan nanocomposite, a pH of 7.0, and temperature of 25 °C. The thermodynamic parameters confirmed the spontaneity and exothermic nature of the 17-β-estradiol sulfate uptake process. The kinetic study revealed a first-order reaction, with the mechanism of uptake attributed to liquid film diffusion. The supra-molecular interaction between β-estradiol and graphene oxide chitosan nanocomposite was elucidated, highlighting the pivotal role of two hydrogen bonds with binding affinities of −6.80 and −7.03 kcal/mole for the first and second hydrogen bonds. This method is speedy, efficacy, and environmentally friendly; making it applicable for the removal of β-estradiol from water in diverse water systems.

Synergistic effects of thermally reduced graphene oxide/zinc oxide composite material on microbial infection for wound healing applications

Infections originating from pathogenic microorganisms can significantly impede the natural wound-healing process. To address this obstacle, innovative bio-active nanomaterials have been developed to enhance antibacterial capabilities. This study focuses on the preparation of nanocomposites from thermally reduced graphene oxide and zinc oxide (TRGO/ZnO). The hydrothermal method was employed to synthesize these nanocomposites, and their physicochemical properties were comprehensively characterized using X-ray diffraction analysis (XRD), High-resolution transmission electron microscopy (HR-TEM), Fourier-transform infrared (FT-IR), Raman spectroscopy, UV-vis, and field-emission scanning electron microscopy (FE-SEM) techniques. Subsequently, the potential of TRGO/ZnO nanocomposites as bio-active materials against wound infection-causing bacteria, including Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, was evaluated. Furthermore, the investigated samples show disrupted bacterial biofilm formation. A reactive oxygen species (ROS) assay was conducted to investigate the mechanism of nanocomposite inhibition against bacteria and for further in-vivo determination of antimicrobial activity. The MTT assay was performed to ensure the safety and biocompatibility of nanocomposite. The results suggest that TRGO/ZnO nanocomposites have the potential to serve as effective bio-active nanomaterials for combating pathogenic microorganisms present in wounds.

Biomolecule-functionalized exfoliated-graphene and graphene oxide as heteronucleants of nanocrystalline apatites to make hybrid nanocomposites with tailored mechanical, luminescent, and biological properties

Nanocrystalline apatite (Ap), known for its exceptional biological properties, faces limitations in hard tissue engineering due to its poor mechanical properties. To overcome this limitation, we investigated the preparation of nanocomposites through heterogeneous nucleation of calcium phosphate on exfoliated graphene (G) and graphene oxide (GO) flakes, selected for their outstanding mechanical properties. The flakes were treated (functionalized) with amino acids of varying isoelectric points—namely L-Arginine (Arg), L-Alanine (Aln) and L-Aspartic acid (Asp)— as well as citrate (Cit) molecules. Furthermore, Tb3+ was incorporated into the formulations to introduce luminescence and further enrich the functionality of the composite. The synthesis was conducted using the sitting drop vapor diffusion method. Functionalized GO/Ap nanocomposites significantly improved roughness, adhesion forces and elastic modulus compared to Ap and G-based particles. GO-Asp-Ap-Tb nanocomposites exhibited the highest roughness (163.8 ± 116.2 nm), while G-Cit-Ap had the lowest (6.8 ± 5.6 nm). In terms of adhesion force, GO-Cit-Ap-Tb reached the highest value (31.06 ± 13.3 nN), while G-Arg-Ap had the lowest (3.7 ± 1.8 nN) compared to Ap (13.6 ± 3.2 nN). For the elastic modulus, GO-Aln-Ap-Tb demonstrated the greatest stiffness (3489 ± 101.01 MPa) compared to Ap (30.2 ± 6.5 MPa), while G-Aln-Ap-Tb showed the lowest (17.2 ± 8.4 MPa). Concerning their luminescence, regardless of G/Ap and GO/Ap, the relative luminescence intensities depended on the biomolecule used and decreased in the order Arg > Aln >Asp and Cit. Furthermore, G/Ap and GO/Ap nanocomposites demonstrated good biocompatibility on murine mesenchymal stem cells at low concentrations, showing cell viabilities exceeding 80% at 0.1 μg/mL. This research offers a novel approach to enhancing the mechanical properties of apatites while preserving their good biocompatibility properties and introducing new functionalities (i.e. luminescence) in the composites, thereby expanding their range of applications in hard tissue engineering.

Ultrasonic-aided preparation of poly(vanillin-co-thiophene)/green Fe₃O₄ nanocomposites via solution mixing for methyl orange adsorption and antibacterial applications

This work describes the preparation of novel nanocomposite materials comprising a newly synthesized semiconducting copolymer, poly(vanillin-co-thiophene) (PVTH), blended with different weight proportions (3 %, 6 %, and 9 % by weight) of greenly synthesized magnetite nanoparticles (GFe3O4 MNPs) via solution mixing, assisted by ultrasonic irradiation. PVTH copolymer was synthesized through the polycondensation of vanillin, a bioderived aldehyde, and thiophene, catalyzed by sulfuric acid. GFe3O4 MNPs were prepared via the coprecipitation method with mint extract as an environmentally friendly stabilizer. The physicochemical properties of the prepared samples were investigated by 1H NMR, 13C NMR, FTIR, XRD, UV–vis, TGA, FE-SEM/Eds, AFM, VSM, tauc plot method and the four-points probe measurement. The samples were evaluated for two applications: methyl orange (MO) adsorption from aqueous solutions and antibacterial activities against Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Bacillus) bacterial strains. The results showed that ultrasound irradiation facilitated the easy preparation of well-dispersed and homogeneous nanocomposites with combined semiconducting and magnetic properties and improved thermal stability compared to the parent PVTH. The most effective nanocomposite for MO removal was the sample containing 9 % GFe3O4 MNPs, whose adsorption behavior followed pseudo-second-order kinetics and Freundlich isotherm. Its maximum adsorption capacity was 103.79 mg g−1. In addition, all samples showed antibacterial action against the tested bacterial strains, with PVTH showing the highest efficacy, followed by PVTH/GFe3O4 nanocomposites.

Biofabrication of GO-Ag nanocomposite using Cucumis callosus (kachri) fruits: Enhanced antibacterial properties and green synthesis approach.

This study presents a novel, environmentally sustainable method for the synthesis of graphene oxide (GO) sheets decorated uniformly with silver nanoparticles (Ag NPs) ranging in size from 4 to 34 nm. The reduction of AgNO3 is achieved using an extract derived from Cucumis callosus fruit, which serves as a dual-function stabilizing and reducing agent. Cucumis callosus, belonging to the Cucurbitaceae family and native to regions such as India, South America, Thailand, Africa, and Egypt, is recognized for its substantial nutritional and medicinal value, encompassing antioxidant, antidiabetic, anticancer, and anti-inflammatory properties. In this study, we explore the utilization of Cucumis callosus extract for the first time in synthesizing Ag NPs, employing a green synthesis approach to produce GO-Ag nanocomposites. Comprehensive characterization techniques confirm the structural integrity and quality of the synthesized nanocomposites. The antibacterial efficacy of the green-synthesized Ag-decorated GO nanocomposites was evaluated using the disk diffusion method against Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) bacteria at varying dosages. The nanocomposites demonstrated dose-dependent antibacterial activity against both bacterial strains, with a notably heightened effect observed against Gram-negative bacteria. These findings underscore the potential of Cucumis callosus as a promising candidate for the sustainable preparation of GO-Ag nanocomposites with enhanced antibacterial properties, suitable for various biomedical and environmental applications. RESEARCH HIGHLIGHTS: This work presents a simple, environmentally free, and cost-effective green synthesis method to decorate uniformly small (4-34 nm) spherical Ag NPs on the GO sheets. Ag NPs were produced by reducing AgNO3 using Cucumis callosus fruit extract as a stabilizing and reducing agent. The nanocomposites show dosage-dependent antibacterial activities against both Gram-positive and Gram-negative bacteria, but the antibacterial effect is higher against the Gram-negative bacteria. Synthesis of these nanocomposites via the green route using an herbal plant/fruit like Cucumis callosus will benefit the medical industry.

Preparation of a rubber nanocomposite for oil/water separation using surface functionalized/silanized carbon black nanoparticles

Clean water is the basic need of living organisms on the earth. Oil spills to free waters is one of the most important threats to living beings. It has been believed that using sorbents is the most effective method for this purpose. In this research, usage of tire rubber with improved hydrophobic properties is considered. For this purpose, carbon black nanoparticles (CBNs) were surface modified with vinyltrimthoxysilane (VTMS) at concentrations of 1, 5 and 10 by sol-gel method. Before, the CBNs were hydroxylated to increase silane grafting content. The surface modified was evaluated using XPS, FTIR, TGA, BET and FESEM analysis. Results showed a great change in the CBNs nature from hydrophilic to hydrophobic after silane modification that could help in more oil absorption and water repletion at the same time. In fact, the water contact angle (WCA) of the CBNs changed from 40 to 135°. The pure and silane grafted CBNs were added to the tire tread compound to prepare elastomeric nanocomposites as oil sorbent. The results showed that the modified nanocomposite had a higher reinforcement index than the samples contained pure and hydroxylated CBNs. The effects of CBNs on WCA, OCA and oil absorption capacity of the samples were also determined. It was found that silane modification a considerable increase in the WCA from 61.2° to 125.03° and a decrease in the oil contact angle (OCA) from 70.01° to 17.74°. Also, the oil absorption capacity of rubber enhanced from 0.55 to 1.95 g/g.

Preparation and Chemosensory Properties of Nanocomposite Obtained by Hydrothermal Modification of Ti2CTx with Hierarchically Organized Co(CO3)0.5(OH)⋅0.11H2O

Preparation and Chemosensory Properties of Nanocomposite Obtained by Hydrothermal Modification of Ti2CTx with Hierarchically Organized Co(CO3)0.5(OH)⋅0.11H2O

Enhancing electrical insulation and thermal conductivity in polydimethylsiloxane polymer nanocomposites through silica coating on carbon fibers

Mesophase pitch-based carbon fibers (MPCFs) exhibit high thermal conductivity (∼900Wm−1K−1) and are considered to be an important candidate for future thermal management. However, MPCFs lead to an increase in the electrical conductivity of nanocomposites due to the low volume electrical resistivity (∼10−3 Ω cm). The development of MPCFs nanocomposites with high thermal conductivity and good electrical insulation remains a challenging problem. In order to solve the problem, we utilized the surfactant cetyltrimethylammonium bromide (CTAB) as an anchor for hydrolysis, and employed a sol-gel method to deposit a silica coating on MPCFs (silica@MPCFs). Silica@MPCFs was used as the filler for polydimethylsiloxane (PDMS) matrix. The nanocomposites exhibit commendable thermal conductivity (achieving 1.52 Wm−1K−1) and excellent volume electrical insulation (exceeding 1013 Ω cm) at a 30 vol% concentration. Notably, both the thermal conductivity and volume electrical insulation exceed MPCFs/PDMS. This approach to electrical insulation treatment holds substantial potential for the future preparation of high-performance nanocomposites of electronic devices.

Targeted assembly of hierarchical sea-urchin inspired NiPS@LDH architecture for enhanced toughness, wear-resistance and fire-safety of epoxy composites

Epoxy resin (EP) is a versatile material widely used in fields such as electronic encapsulation, coatings, adhesives, and composites. The targeted assembly of nanomaterials to optimize the flame retardancy, mechanical properties, and interfacial properties of composite materials is a prominent research hotspot in the field of EP. Therefore, a hierarchical sea-urchin inspired architecture (NiPS@LDH), based on layered double hydroxide (LDH) nanosheets grown on nickel phyllosilicate (NiPS), was rationally constructed as a functional filler for EP with a view to building high-performance EP composites. The addition of 1 wt% NiPS@LDH increased the tensile strength, modulus of elasticity, and elongation at break of EP by 44.1 %, 27.6 %, and 66.2 %, respectively, showing excellent strengthening and toughening effects. Meanwhile, under dry friction conditions, the wear rate of the composites was 0.86 mm3·N−1·m−1, reduced by 87.8 % compared to that of pure EP, indicating excellent wear resistance. Besides, the pHRR, THR, pSPR, TSP, pCO and pCO₂ of EP/NiPS@LDH-3 composites were found to be significantly reduced by 54.0 %, 61.9 %, 50.7 %, 54.4 %, 51.2 %, and 58.2 %, respectively. The LOI value of the composites increased to 26.4 %, and the maximum weight loss (Rmax) was reduced by 27.7 %. This study provides an innovative strategy for the targeted assembly of nanomaterials, paving the way for the preparation of high-performance EP nanocomposites.

Properties of EPDM Nanocomposites Reinforced with Modified Montmorillonite.

Considering the dilemma of obtaining economic and high-performance composites based on non-polar and main-chain-saturated ethylene propylene diene monomer rubber (EPDM), we proposed an effective and universal filler modification and nanocomposite preparation method. Specifically, the montmorillonite (MMT) surface was coated with polydopamine (PDA) to obtain DMMT, which was confirmed by XRD, XPS, FTIR, and TGA. After compounding DMMT gel with the solid EPDM via the gel compounding method, a silane coupling agent, vinyltrimethoxysilane, was introduced to construct covalent interactions between rubber and filler. Compared with the unmodified MMT filler EPDM, the EPDM/DMMT nanocomposite showed much fewer filler aggregates in the matrix. The highest tensile strength of the composites reached 6.5 MPa with 10 phr DMMT, almost 200% higher than that of pure EPDM.

In‐situ preparation of modified‐halloysite/thermoset nanocomposites via thiol‐epoxy click chemistry

AbstractIn the current study, thermoset nanocomposites including halloysite nanotubes (HNTs) have been prepared through thiol‐epoxy click reaction at ambient conditions. Naturally available HNTs are first modified separately by epoxy and thiol groups and used as nanofillers in a mixture of trimethylolpropane triglycidyl ether and trimethylolpropane tris(3‐mercaptopropionate) ranging from 0 to 5 wt%. Fourier transformed infrared (FT‐IR) spectroscopy has been used to observe the characteristic bands of the pure and modified halloysite, neat thermoset, and HNT/thermoset nanocomposites. Thermal properties of epoxide‐modified and thiol‐modified halloysite nanotubes and also final thermoset nanocomposites have been investigated using thermogravimetric analysis (TGA) by comparing pure halloysite and neat thermoset, respectively. The dispersion of HNT nanotubes in thermoset matrix has been examined with scanning electron microscopy (SEM). In addition to the agglomerated/non‐agglomerated distribution, the present of HNT has been proved by EDX. The effect of HNT‐Epoxide and HNT‐Thiol loadings on mechanical properties has been examined by tensile test. All nanocomposites were found to exhibit better tensile strength than that of neat thermoset, called as reference sample. The most enhanced mechanical properties have been detected in the nanocomposite with 3% modified‐HNTs by weight because of the best dispersion, which promotes effective interactions between the nanotubes and thermoset matrix. Tensile strength of thermoset nanocomposites increased by 43% and 62%, while elongation at break increased by 58% and 149% when 3 wt% HNT‐Epoxide and 3 wt% HNT‐Thiol were added to the matrix, respectively. Further increase of HNT added to the matrix causes agglomeration of nanotubes and thus deterioration of mechanical properties.Highlights Pure HNT was modified and successfully converted into HNT‐Epoxide and HNT‐Thiol. In‐situ preparation of thermoset nanocomposites with modified‐HNTs was effectively achieved via thiol‐epoxy click chemistry. Mechanical properties increased significantly with both HNT‐Epoxide and HNT‐Thiol loading ratio up to 3 wt%. The presence and agglomerated/non‐agglomerated dispersion of modified‐HNTs in the thermoset matrix were verified by SEM–EDX analysis.