Preparation Of Nanocomposites Research Articles

Graphene-Based Polymer Nanocomposites Preparation and Their Advantages

Graphene and its derivatives have attracted the attention of researchers since its discovery due to its surprising properties. Since then, scientists have been trying to improve the processes that allow the incorporation of this material into polymeric matrices, to improve them, through the development of graphene-based polymeric nanocomposites. This review study reviewed these methods meticulously. Furthermore, it has already been cataloged that adding small amounts of graphene nano-fillers tends to improve the polymers’ mechanical, electrical, and thermal properties.

A brief review on preparation and application of MWCNT-based polymer nanocomposites

Technological advancementalways seeks new materials with improved functional properties, particularly for smart applications. In this regard, nanotechnology is offering today wide range of novel material designs fabricated by compounding nanofillers into the polymer matrix. Different allotropic forms of carbon can reinforce the properties of polymers for various applications. Reinforcement depends on the dimension, shape, size and compatibility of the nanofiller with the polymer matrix. Chemical modification of filler surfaces and the matrix can selectively localize the filler in the hybrid composites in the desired phase or at the interface by melt mixing or solution casting method, during compounding procedure. In this regard, the conducting nature of the additioin of multiwalled carbon nanotubes (MWCNTs) into a polymer matrix fosters the conductivity into the materials. Such nanocomposites can be used for numerous applications such as conducting materials, super-capacitors, light emitting devices, medical purposes etc,. This review paper focuses on different methods of preparation of MWCNT/polymer nanocomposites, their surface properties, and microbial properties etc,.

Mechanical and Thermophysical Properties of Epoxy Nanocomposites with Titanium Dioxide Nanoparticles

The introduction of nanoparticles and their homogeneous distribution in the polymer matrix, as well as their size, can have a significant effect on the mechanical properties of composite materials. In this work, we studied the mechanical characteristics of TiO2/epoxy nanocomposites with different contents and sizes of nanoparticles. The preparation of nanocomposites was carried out by a stepwise curing (at 90 and 160 °C) of ED-20 dianic epoxy resin in the presence of an aromatic hardener with the addition of titanium (IV) dioxide nanoparticles preliminarily synthesized by the plasma-chemical method. Ultrasonic dispersion was used to achieve a uniform distribution of nanoparticles in the polymer matrix. The chemical and phase composition, the structure of the as-synthesized TiO2 nanoparticles, and the resulting epoxy nanocomposites were characterized by elemental analysis, X-ray diffraction, transmission and scanning electron microscopy, and infrared spectroscopy. The mechanical properties of the nanocomposites were determined by the static tensile test, and the impact toughness was determined by the Charpy method. The glass transition temperature and thermal stability of the TiO2/epoxy nanocomposites were studied by thermal analysis methods. The formation of an interfacial layer between the TiO2 nanoparticles and an epoxy matrix has been shown for the first time by spectral methods. It is shown that the mode of curing and ultrasonic dispersion used, as well as varying the content and dispersity of the TiO2 nanoparticles, make it possible to obtain epoxy nanocomposites with simultaneously improved deformation-strength characteristics and impact strength values.

Preparation and Properties of Nanocomposite Based on K-153 Epoxy Reinforced T-13 Glass Fiber

This study aims to investigate the influence of nanosilica content and the ratio of glass fiber/epoxy resin on the mechanical properties of nanocomposites based on K-153 epoxy resin (K-153) matrix reinforced by T-13 glass fiber (T-13). Thermogravimetric Analysis (TGA), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray Analysis (EDX) were used to examine the results of the investigations. The findings showed that the nanosilica of 1.20 weight percent (wt.%) was suitable for making K-153/T-13/nanosilica nanocomposites. Compared to K-153/T-13 polymer composites, K-153/T-13/nanosilica nanocomposites with nanosilica content of 0- 1.2 wt.% and the ratio of T-13 glass fiber/K-153 epoxy resin at 70/30 wt.%, the tensile strength had increased from 215.41 MPa to 313.12 MPa and from 230.96 MPa to 325.35 MPa for flexural strength. Besides that, the thermal resistance of nanocomposites also increases compared to that of polymer composites based on K-153 epoxy resin. At 500 °C, the weight loss of nanocomposites and polymer composites was 34.01 % and 37.67 %, respectively.

Hydroxyapatite-nanosilver composites with plasmonic properties for application in surface-enhanced Raman spectroscopy

Two routes for preparation of nanocomposites based on hydroxyapatite (HA) doped with Ag nanoparticles (HA@AgNPs) were investigated aiming towards the development of novel materials for sensing and biomedical applications. Both routes are based on using commercially available HA and Creighton colloidal silver prepared by reduction of silver nitrate with sodium borohydride. A number of composites with different HA to Ag ratios were synthesized and evaluated by transmission electron microscopy, X-ray diffraction analysis, infrared and Raman spectroscopy. It was found that the position of phosphate band in 940–970 cm−1 range of Raman spectra can be used as an independent marker of successful HA loading with Ag NPs in addition to XRD analysis. The ability of HA@AgNPs nanocomposites to localized surface plasmon resonance was demonstrated by the UV-Vis spectroscopy and surface-enhanced Raman scattering (SERS) study performed with acridine as a test molecule. The grafted SERS activity can be utilized for optical control of bone healing either for identification of various analytes, participating in bone metabolism.

Preparation of photoluminescent nanocomposite by one-step method from cobalt oxide-Jeffamine based on novel polymer dot as a high-performance and ultra-stable symmetric supercapacitor

Polymer dots are a new class of quantum dots that have attracted much attention from researchers. Based on, in this work, for the first time, using a one-step method, the new PDJA-Co3O4 nanocomposite with a quantum yield of 65.45%, based on the polymer dot of jeffamine was synthesized, which has ideal supercapacitor properties. The new polymer dot-based Jeffamine (PDJA) was first synthesized using a Jeffamine polymer and simultaneously composited with cobalt oxide by the solvothermal method. The photoluminescence properties and supercapacitor performance of the PDJA-Co3O4 nanocomposite and the PDJA were investigated. The PDJA-Co3O4 nanocomposite and the PDJA were prepared as electrode materials, and analysis of CV, GCD, and EIS was performed that the specific capacitance of the PDJA-Co3O4 nanocomposite electrode material and the PDJA electrode material are 978 F.g−1 and 283 F.g−1 at 50 mV/s, respectively. Also, the PDJA-Co3O4 nanocomposite and the PDJA have cyclic stability of 98.37% and 91.57% up to 10,000 cycles of cyclic voltammetry at 100 mV/s, respectively. Then, two symmetric supercapacitors were manufactured of the PDJA-Co3O4 nanocomposite and the PDJA. Finally, due to the high conductivity of the PDJA-Co3O4 nanocomposite active material, the symmetric supercapacitor of PDJA-Co3O4 nanocomposite turned on the LED lamp.

Wearable and Stretchable SEBS/CB Polymer Conductive Strand as a Piezoresistive Strain Sensor

A wearable and stretchable strain sensor with a gauge factor above 23 was prepared using a simple and effective technique. Conducting nanocomposite strands were prepared from styrene-b-(ethylene-co-butylene)-b-styrene triblock copolymer (SEBS) and carbon black (CB) through a solvent-processing method that uses a syringe pump. This novel nanocomposite preparation technique is a straightforward and cost-effective process and is reported in the literature for the first time. The work included two stages: the flexible nanocomposite preparation stage and the piezoresistive sensor stage. Depending on its molecular structure, the thermoelastic polymer SEBS is highly resilient to stress and strain. The main aim of this work is to fabricate a highly flexible and piezoresistive nanocomposite fibre/strand. Among the prepared composites, a composite corresponding to a composition just above the percolation threshold was selected to prepare the strain sensor, which exhibited good flexibility and conductivity and a large piezoresistive effect that was linearly dependent on the applied strain. The prepared nanocomposite sensor was stitched onto a sports T-shirt. Commercially available knee and elbow sleeves were also purchased, and the nanocomposite SEBS/CB strands were sewn separately on the two sleeves. The results showed a high sensitivity of the sensing element in the case of breathing activity (normal breathing, a 35% change, and deep breathing at 135%, respectively). In the case of knee and elbow movements, simultaneous measurements were performed and found that the sensor was able to detect movement cycles during walking.

Fabrication of gallic acid electrochemical sensor based on interconnected Super-P carbon black@mesoporous silica nanocomposite modified glassy carbon electrode

The efficient and accurate detection of gallic acid (GA) is particularly important for human health. Herein, a simple and low-cost ultrasonic-assisted strategy was proposed for the preparation of multifunctional nanocomposite of Super-P carbon black (SPCB) nanoparticles and mesoporous silica nanoparticles (MSNs), which was used to modify the glassy carbon electrode (GCE) for the fabrication of GA electrochemical sensor (SPCB@MSNs/GCE). SPCB with pearl-chain nanostructure presented an interconnected highly conductive carbon network, which significantly improved the charge transfer efficiency. MSNs with spherical morphology and mesoporous structure exhibited uniform particle dispersion and high active surface area, which remarkably improved the surface accumulation effect of sensing electrode towards GA. Moreover, the excellent electrical conductivity of SPCB compensated for the non-conductive property of MSNs. Under the optimized condition, the electrochemical response of SPCB@MSNs/GCE sensor had a good linear relationship with GA concentration (0.5–10 μM), and the corresponding limit of detection could reach up to 4.911 nM. The fabricated nanohybrid sensor showed good reproducibility, repeatability and anti-interference property. Moreover, the satisfactory GA recoveries and RSD values were achieved for the electrochemical detection of GA in tea samples. This work provides an important reference for the highly sensitive analysis of GA in the field of food safety.

Preparation and properties of multifunctional polyurethane synthetic leather nanocomposites

Although leather can be functionally modified well, its origin will cause concern about the destruction of the ecological environment. Here, a novel multifunctional synthetic leather (denoted as FRTL) that integrates high tensile strength, flame retardancy, Joule heating, electromagnetic shielding, and strain sensing is reported. Benefiting from the excellent mechanical properties of the PU film, the leather exhibits a high tensile strength of 100.8 MPa. Based on the high conductivity of MXene, the leather possesses an electromagnetic shielding efficiency of 30.1 dB. FRTL also exhibits excellent flame retardancy, confirmed by the reduction of more than 32% in peak heat release rate. In addition, the controlled Joule heating properties enable the leather to cope with extreme cold weather. The obtained fabric can also detect various human movements. This work provides a facile method to fabricate the next-generation multifunctional protective leather, showing promising application in the field of smart firefighting.

Confining Fluorescence Detection for Distinguishable Visualization of Multivariate Nanoparticles: Implications for Design and Controllable Preparation of Nanocomposites

Confining Fluorescence Detection for Distinguishable Visualization of Multivariate Nanoparticles: Implications for Design and Controllable Preparation of Nanocomposites

Critical role of water in fused silica glass by silica nanopowder sintering: Nanoparticle dispersion

Thermoplastic nanocomposite preparation using a silica nanopowder/polyethylene glycol (PEG) / polyvinyl butyral (PVB) system followed by heat-treatment sintering to obtain fused silica glass has high precision, scalable manufacturing processes, and short processing time. However, conventional solvents are toxic and harmful to the environment, and for this reason, the ethanol/water solvent system was proposed in this study. In this study, the effect of water content on the dispersion effect of nano-silica suspensions was investigated through particle size and zeta potential tests and FTIR spectra analysis; in addition, the study proposes a dispersion theory based on the solvation layer of the ethanol/water competitive adsorption and viscosity effect. Finally, optical photographs and SEM characterization showed that the obtained fused silica glass was transparent and had no seam defects, and the XRD and hydroxyl group tests showed that the glass had a low hydroxyl group content of only 2.55 ppm.

Optimal Design of Carbon-Based Polymer Nanocomposites Preparation Based on Response Surface Methodology

Response surface methodology (RSM) and central composite design (CCD) were used to improve the preparation of carbon nanotube and graphene (CNT-GN)-sensing unit composite materials in this study. Four independent variable factors (CNT content, GN content, mixing time, and curing temperature) were controlled at five levels, and 30 samples were generated using the multivariate control analysis technique. On the basis of the experimental design, semi-empirical equations were developed and utilized to predict the sensitivity and compression modulus of the generated samples. The results reveal a strong correlation between the experimental and expected values of sensitivity and the compression modulus for the CNT-GN/RTV (room-temperature-vulcanized silicone rubber) polymer nanocomposites fabricated using different design strategies. The correlation coefficients for the sensitivity and compression modulus are R2 =0.9634 and R2=0.9115, respectively. The ideal preparation parameters of the composite in the experimental range include a CNT content of 1.1 g, a GN content of 1.0 g, a mixing time of 15 min, and a curing temperature of 68.6 °C, according to theoretical predictions and experimental findings. At 0~30 kPa, the CNT-GN/RTV-sensing unit composite materials may reach a sensitivity of 0.385 kPa-1 and a compressive modulus of 601.567 kPa. This provides a new idea for the preparation of flexible sensor cells and reduces the time and economic cost of experiments.

Preparation of Cellulose Hydrogels and Hydrogel Nanocomposites Reinforced by Crystalline Cellulose Nanofibers (CNFs) as a Water Reservoir for Agriculture Use

An effective strategy for the management of available water and fertilizers is imperative to improve agricultural production and food quality, including releasing them sustainably to the soil and plants. Polymeric hydrogels with three-dimensional (3D) networks can absorb ample water and soluble fertilizers without network dissolution. Subsequently, the absorbed water and fertilizers can be released to arid and semi-arid agricultural land to furnish enough moisture and nutrients for plant growth. In this study, carboxymethyl cellulose sodium salt (NaCMC)- and hydroxyethyl cellulose (HEC)-based hydrogels have been synthesized using citric acid (CA) as a crosslinker. The Fourier transform infrared (FTIR) spectroscopy study revealed the formation of hydrogels with porous structures depicted by field emission scanning electron microscopy images. The prepared hydrogels have shown a remarkable swelling ratio of ∼1070% for the hydrogel prepared using NaCMC/HEC: 2/1 and ∼840% for NaCMC/HEC: 3/1 and a reduction in the swelling ratio with increasing crosslinking density. Moreover, crystalline (shown by X-ray diffraction) cellulose nanofibers (CNFs: ∼600 nm), prepared by acid (H2SO4) hydrolysis of cotton fibers, have been used to prepare hydrogel nanocomposites. The evaluation of hydrogel nanocomposites’ mechanical properties (universal testing matching test) depicted an improved tensile strength (16.27 MPa using 0.7% CNFs) compared to that of the hydrogel without CNFs. The soil burial test for biodegradation study of prepared hydrogels revealed soil degradation of hydrogel, confirmed by FTIR analysis and visual appearance. The current study provides comprehensive data establishing the potential of hydrogels for agriculture applications.

Preparation and characterization of nanocomposites based on chitosan with ZnO-Curcumin

The present paper studied the possibility to obtain nanocomposites of chitosan incorporated with ZnO NP, whose surface has been modified with bioactive compounds. To obtain ZnO nanoparticles, the biogenic method was used and the anchoring of curcumin (CRC) on the surface of the particles was followed. Chitosan-based ZnO-CRC were synthesized using ex-situ method that involves the separate preparation of ZnO particles and their dispersion in the chitosan matrix by mechanical and ultrasonic mixing. The structural and morphological studies of the synthesized samples were carried out using X-ray diffraction, SEM microscopy, FTIR and EDX spectroscopy, and the wetting capacity. The XRD analysis revealed wurtzite crystalline structure of ZnO, anchoring of curcumin to the oxide surface, with an average crystallite size about 18.7 nm. The morphological study shows that the particles have spherical formations, with dimensions in the nanometric range and a relatively uniform distribution of ZnO particles in the matrix. Elemental composition of samples was identified using EDX analysis. Contact angle was measured to evaluate the hydrophilic and/or hydrophobic character of the surfaces. The results demonstrate that the synthesized materials have morpho-structural and wetting characteristics that allow the extension of applicability in biotechnological fields as coating systems.

Fabrication of activated carbon coated MSe2 (M=Mo, Co, and Ni) nanocomposite electrode for high-performance aqueous asymmetric supercapacitor

Transition metal diselenides are trendy electrode materials for supercapacitors. The main reason behind it is their high specific capacitance. But, they suffer from poor electronic conductivity and agglomeration issues which hinder their practical use. Herein, we present the preparation of nanocomposites including transition metal diselenide MSe2 (M=Mo, Co, and Ni) with activated carbon using the facial hydrothermal route. Inspiring from the high electrochemical results of a hybrid nanocomposites symmetric cell, an aqueous asymmetric ultracapacitor cell (AUC) comprised of different shaped carbon-coated MSe2 (positive electrode) as well as activated carbon (AC) (negative electrode) has been fabricated. The NAC//6KOH//AC asymmetric cell displays the best outcomes among all fabricated devices. The specific capacitance observed is about 3740 F g−1 at 10 mV s−1. It delivers a high energy density of 69 Wh kg−1 along with a power density of 687 W kg−1 at 1 A g−1. The electrochemical results motivate us to explore the practical usability of the prepared NAC//6KOH//AC device via illuminating 26 red LED panels which glow for 26 min. The findings in this report indicate that MSe2-based nanocomposite has the scope and is a potential material in the energy storage field.

Recent progress of applied TiO2 photoelectrocatalysis for the degradation of organic pollutants in wastewaters

Photoelectrocatalysis (PEC) is a promising powerful electrochemical advanced oxidation process (EAOP) that combines photocatalysis and electrolysis. Upon light irradiation over a semiconductor photocatalyst, electrons of its valence band are promoted to its conduction band giving rise to positively charged holes. The external bias potential applied to the photoanode extracts the photoexcited electrons toward the cathode of the electrolytic cell. Organics can then be oxidized directly by the holes or with hydroxyl radical formed by their reaction with H2O/OH−, and at lesser extent with other reactive oxygen species formed. The extensive study of TiO2 photoanodic nanomaterials and their applicability in environmental remediation makes necessary a further analysis of the state of the art and the actual understanding of potentials and shortcomings. This paper presents a comprehensive and critical review on the application of PEC with TiO2 photoanodes to remove organic pollutants from wastewaters from 2017 to May 2022. Fundamentals of this technique with pristine TiO2 photoanodes are explained, with special emphasis on the understanding of ROS origination mechanisms and the analytical techniques used for their characterization. Typical PEC systems and key operating variables related to the effectiveness of the process are examined. Recent advances obtained by TiO2 and TiO2-based photoanodes treatment of chemicals, dyes, pharmaceuticals, and pesticides are described and discussed. The preparation of TiO2 nanocomposites and their heterojunction mechanism, as well as the application of hybrid processes are detailed. Finally, prospects are proposed for the future research of PEC with perspectives to industrial application at higher technology readiness level.

First principles calculation study of single transition metal atom grafted Au25 as efficient electrocatalysts for OER and ORR

The method of grafting metal atoms by ligands can construct 'grafted single-atom catalysts' with good catalytic activity without destroying the cluster structure. In this study, the catalytic performance of Fe2+, Co2+ and Ni2+ grafted Au25(SR)18 cluster through l-cysteine ligand as bridging ligand (denoted as Au25-nCys-M, where n is the number of grafted Cys-ligand) in OER and ORR was investigated by density functional theory (DFT) simulations. A volcanic diagram between the overpotential of OER and ORR and the adsorption free energy of intermediates on Au25–nCys-M was determined, which showed that the adsorption strength of oxygenated intermediates can be adjusted by the grafting method and the number of bridging ligands, thus affecting the catalytic performance. Among three kinds of metal ions, the grafted Ni2+single atom catalysts showed excellent bi-functional OER and ORR activities. In particular, the Au25–1Cys-Ni2+ (n = 1) had the lowest overpotentials of 0.48 and 0.27 V for OER and ORR. Through in-depth analysis, we found that the spin magnetic moments of metal cations can be used as the descriptor of the catalytic performance of the grafted single atom catalyst. The excellent catalytic performance of Au25–nCys-Ni2+was originated from the smaller spin magnetic moment of Ni2+. These findings provided new idea for the preparation of nanocomposites with excellent OER and ORR catalytic performance.

Extraction of crystalline nanocellulose (CNC) from date palm mat fibers and its application in the production of nanocomposites with polyvinyl alcohol and polyvinylpyrrolidone blended films

The preparation of polymer nanocomposites has drawn a lot of interest because of its numerous industrial uses. The chemical composition of the date palm mat (DPM) fibers was analyzed. Raw DPM fibers were used to extract the cellulose, which was then converted into crystalline nanocellulose (CNC) by acid hydrolysis. Extraction of CNC from raw DPMs was confirmed by FTIR, Particle size and SEM studies. The results of the zeta potential test showed that CNC had good stability. This CNC was used as a reinforcing material to create nanocomposite films. The CNC reinforced PVA and PVA/PVP nanocomposite films were made utilizing the solution casting technique with varying weight percentage from 3 to 12% CNC. Tensile characteristics, SEM, and water absorption characteristics of nanocomposite films were examined. The tensile characteristics of the nanocomposite films showed a noticeable improvement.

Green metal oxides coated biochar nanocomposites preparation and its utilization in vertical flow constructed wetlands for reactive dye removal: Performance and kinetics studies

Major causes of water pollution in the ecosystem are pollutants such as dyes which are noxious. The present study was based on the synthesis of the green nano-biochar composites from cornstalk and green metal oxide resulting in Copper oxide/biochar, Zinc oxide /biochar, Magnesium oxide/biochar, Manganese oxide/biochar, biochar for removal of dyes combined with the constructed wetland (CW). Biochar Augmentation in constructed wetland systems has improved dye removal efficiency to 95% in order of copper oxide/biochar > Magnesium oxide/biochar > Zinc oxide/biochar > Manganese oxide/biochar > biochar > control (without biochar) respectively in wetlands. It has increased the efficiency of pH by maintaining pH 6.9–7.4, while Total Suspended Solids (TSS) removal efficiency and Dissolved oxygen (DO) increased with the hydraulic retention time of about 7 days for 10 weeks. Chemical oxygen demand (COD) and colour removal efficiency increased with the hydraulic retention time of 12 days for 2 months and there was a low removal efficiency for total dissolved solids (TDS) from control (10.11%) to Copper oxide /biochar (64.44%) and Electrical conductivity (EC) from control (8%) to Copper oxide /biochar (68%) with the hydraulic retention time of about 7 days for 10 weeks. Colour and chemical oxygen demand removal kinetics followed second and first-order kinetic. A significant growth in the plants were also observed. These results proposed the use of agricultural waste-based biochar as part of a constructed wetland substratum can provide enhanced removal of textile dyes. That can be reused.

Mechanical Characterization Study of Additive as Nanofiller in Poly (ε-Caprolactone) Nanocomposite

In order to keep with ever evolving technology in biomedical field, the demand for Poly (ε-caprolactone) (PCL) is gaining importance due to its biodegradability and biocompatibility. However, the low mechanical, barrier and thermal strength of PCL restricts its widespread use. These drawbacks of virgin PCL can be rectified by incorporating nanofiller into the PCL matrix. Till date, research has been carried out incorporating nano-fiber into PCL but to the best of our knowledge there is hardly any literature regarding organoclay modified nanofiller-PCL composites. The present study represents PCL nanocomposites preparation and characterization. The FTIR and XRD spectra observe uniform distribution of nanofiller in the PCL matrix. The characterization of mechanical properties shows enhancement in strength till 3.5 wt% loading and declining trend afterwards indicating agglomeration of nanofiller at higher wt% ratio. The increase in tensile strength without sacrificing elongation at break provides these composites with very attractive mechanical properties.