Preparation Of Nanocomposites Research Articles

One-pot hydrothermal preparation of capsule-like nanocomposites of C/Ce-co-doped ZnO supported on graphene to enhance photodegradation

Nanocapsule composites of C/Ce-co-doped ZnO supported on graphene synthesized by a one-pot hydrothermal method with a band gap of 2.72 eV were used to enhance the photodegradation of methylene blue under various conditions.

Preparation and characterization of conducting silk fibroin by Ag nanocoating for electrical applications

This research work proposes the fabrication of novel bio-based multifunctional biomaterials in order to avoid synthetic materials to reduce environmental hazards for the sustainability of nature. The decoration of Ag nanoparticles on silk fibroin (SF) surface to achieve the transport properties of SF. This functional biomaterial has numerous amino acid residues so that it acts as a good reducing and stabilizing agent for conversion of metal ions into a neutral atom (Ag+ to Agο). A standard protocol is adopted for the preparation of SF and Ag-coated SF nanocomposites under the influence of light radiation (Incandescent bulb). The SF-AgNPs composites were subjected to XRD, TGA, DSC, SEM, AC & DC conductivity to investigate the structural, thermal and surface morphology and electrical properties of the composites. The formed nanoparticles exhibit a face-centered cubic structure (FCC) with an average particle size of 35–40 nm. The features of SF are altered by the inclusion of AgNPs on the fibroin surface. Since silk is an excellent dielectric material with strong electrical and heat stability after mixing with AgNPs, it can be used for wearable electronic devices and biomedical applications.

Molybdenum sulfo-selenide nanocomposites with carbon nanotubes and reduced graphene oxide for photocatalytic hydrogen evolution reaction

We report a facile method for the preparation of nanocomposites of molybdenum sulfo-selenide (MoSxSe1−x) with carbon nanotubes (CNTs) and reduced graphene oxide (RGO) via a solvothermal approach.

Interfacial stress transfer in monolayer and few-layer MoS2 nanosheets in model nanocomposites

Understanding the stress transfer mechanisms from a polymer matrix to two-dimensional (2D) reinforcements is essential for the preparation of high performance nanocomposites. In this study, the interfacial stress transfer from a flexible polymer substrate to monolayer and few-layer molybdenum disulfide (MoS2) under tension has been investigated. Layer-dependent and strain-dependent photoluminescence (PL) spectroscopy were used to examine the stress transfer efficiency. The interlayer stress transfer efficiency of MoS2 was determined to be in the range of 0.76–0.86, higher than that of graphene. The transfer of strain from the polymer substrate to the flakes was derived through strain-dependent band shifts. With progressive loading, the strain distribution in monolayer MoS2 can be described by the shear-lag, partial-debonding and total-debonding models. The interfacial shear and frictional stresses were calculated to quantify the strength of the MoS2/polymer interface. It was found that the strength of the interface is similar to the strength of a graphene-polymer interface. Strain mapping was performed at different strain levels and it was found that the strain distribution in bilayer MoS2 is similar to the case of a monolayer sample. The interfacial shear strength remains almost unaffected, while the stress transfer length increases with increasing layer number.

Synthesis of photoactive nanocomposite hydrogels via in-situ photoinitiated thiol-ene click polymerization of acrylates containing norbornene-POSS and norbornene-POSS/Ag NPs

Radical-mediated thiol-ene photopolymerization is a method that has been studied intensively since the beginning of the century due to the nature of click chemistry which can be carried out in a fast, controllable, and easy way under mild environment conditions with no or minimal formation of by-products. In order to improve the properties of the polymeric nanocomposite materials which have been obtained by photopolymerization method and to prepare them for a particular purpose, various nano-sized photo-reactive groups or cross-linking agents have been added to the formulations. The advantage of this study for the preparation of thin-film and hydrogel nanocomposites is based on one-pot thiol-ene photo-click polymerization. The main contribution made by one-component Type II photoinitiator, 2-Mercaptothioxanthone (TX-SH) carries both thiol functionality and chromophoric group on it. Polyhedral oligomeric silsesquioxane (POSS) functionalized with 1 or 3 norbornene units was used as alkene and played a good role in the preparation of nanocomposite hydrogels with/without in-situ formed silver nanoparticles (Ag NPs) with various acrylate content by thiol-ene photo-click polymerization. Especially the good contribution of norbornenylethyl disilanol isobutyl polyhedral oligomeric silsesquioxane (1NBPOSS) or tris-norbornenyl isobutyl polyhedral oligomeric silsesquioxane (3NBPOSS) was seen in terms of conversion percentage of acrylates which was determined by photo differential scanning calorimetry (photo-DSC) and swelling ratios of hydrogels in phosphate buffer solution (PBS) buffer solution. Besides them, obtained nanocomposites displayed good thermal stability values according to the Thermogravimetric analysis (TGA) measurements and scanning electron microscopy (SEM) images confirmed rather small-sized and uniform in-situ formed Ag NPs.

Chitosan/Silica Nanocomposite Preparation from Shrimp Shell and Its Adsorption Performance for Methylene Blue

In this study, novel chitosan/silica composites with different mass ratios were prepared by in-situ hydrolysis using chitosan (from shrimp shell) as a carrier, triblock copolymer (P123) as the structure-directing agent, and ethyl orthosilicate as a silicon source. These nanocomposites were characterized by different techniques, including the FT-IR, XRD, TGA, SEM, TEM and N2 adsorption–desorption. The results indicated that the morphology and properties of composites changed with the introduction of silica. When the CS/TEOS mass ratio was 0.0775, the CS−2/SiO2 composite displayed a coral-like three-dimensional porous structure with specific surface area of 640.37 m2/g and average pore size of 1.869 nm. The adsorption properties for methylene blue (MB) were investigated as well and the CS−2/SiO2 showed better adsorption performance. The removal rate for MB reached 94.01% with absorbents dosage of 6 g/L, initial concentration of 40 mg/L, initial pH value of 7, temperature of 35 °C, and adsorption time of 40 min. The adsorption process well fitted the Langmuir isothermal model and quasi-second-order adsorption kinetics model. The maximum adsorption capacity for MB was 13.966 mg/g based on Langmuir fitting. The surface functional groups of the composites can play an important role in the adsorption. The adsorption mechanism of CS−2/SiO2 on MB involved electrostatic interaction, hydrogen bonding and functional group complexation. In addition, the prepared chitosan/silica composites showed good reusability at six cycles, making them a promising material in the application of removing dyeing wastewater.

Preparation and properties of environmentally benign waterborne polyurethane composites from sodium-alginate-modified nano calcium carbonate

Well-dispersed inorganic nanoparticles in organic polymers are critical in the preparation of high-performance nanocomposites. This study prepared a series of waterborne polyurethane (WPU)/calcium carbonate nanocomposites using the solution blending method. Next, FT-IR, TG-DTG and XRD tests were carried out to confirm that the biopolymer sodium alginate (SA) was successfully encapsulated on the surface of the calcium carbonate nanoparticles, and that SA achieved satisfactory surface modification of the calcium carbonate nanoparticles. The Zeta and ultraviolet (UV) absorbance test results reveal that SA-modified nano calcium carbonate (MCC) had good dispersion stability in water. The effects of the MCC dosage on the composite mechanical properties, thermal stability, and cross-sectional morphology observed by scanning electron microscopy, and the water resistance of the nanocomposite were investigated. The results reveal that the incorporation of 3wt% of MCC in WPU had stable distribution, which led to a 54% increase in the tensile strength of the nanocomposite, while maintaining excellent elongation at break (2187%) and increasing the maximum decomposition temperature to 419.6 °C. Importantly, the improved water resistance facilitates the application of this environmentally benign composite material in humid environments.

A novel approach for preparation of nanocomposites with an excellent rigidity/deformability balance based on reinforced HDPE with halloysite

An innovative approach, designated as supported activator (SA), allows preparation of high density polyethylene (HDPE)-based highly performant hybrid materials. This procedure makes use of a nano-sized supported methylaluminoxane (MAO)-activator, based on halloysite natural nanotubes (HNT), combined with an in situ supporting concept. The new protocol when compared with a more conventional approach gives rise to higher polymerization activities as well as ultimate materials with better morphological features, greater crystallinity, thicker crystals, and highly increased stiffness. Moreover, a remarkable synergy between rigidity and toughness is attained. The Young’s modulus of a film obtained from the nanocomposite with the highest HNT content increases more than 70 % relatively to a pristine HDPE film, while retaining the limit stretching ability of pristine HDPE (more than 800%). A beneficial impact of using a high aspect ratio support such as HNT in the mechanical properties is also observed, when compared to similar HDPE hybrid materials derived from dendrimer-like silica (DS) nanospheres. Interestingly, polymerization activity, polymer features and derived properties found in the ultimate materials are less impacted by support/filler nature than by preparation method. This fact highlights the crucial role of the synthetic methodology used and corroborates the high potential of the SA route for the preparation of high-performance polyethylene-based nanocomposites with an excellent balance between stiffness and deformability.

Modified Thermosets – A Review

Recent and extensive reports on the development of preparation methods that can lead to obtaining various nanostructured polymeric materials, including the preparation of nanoparticles, nano-capsules, nano-gels, nano-fibres, dendrimers and nano-composites, have been presented in the literature to provide a picture of the complexity of the field, and the diversity of approaching methods. From the data presented by various researchers, it appears that by ensuring a rigorous control of the nano-structuration of polymers and/or by adding nano-particles to the polymer matrices, improvements in structural and functional properties can be achieved in a significant number of polymer systems as a response to the continuous demands of industrial advanced sectors. Until now, most of the studies on polymer blends have been related to the control of their physical and chemical properties, their barrier properties or their electrical conductivity. This paper briefly presents various applications of resins (thermoset polymers) used to synthesize some polymer materials and blends.

Preparation and Applications of Green Thermoplastic and Thermosetting Nanocomposites Based on Nanolignin.

The development of bio-based materials is of great importance in the present environmental circumstances; hence, research has greatly advanced in the valorization of lignin from lignocellulosic wastes. Lignin is a natural polymer with a crosslinked structure, valuable antiradical activity, unique thermal- and UV-absorption properties, and biodegradability, which justify its use in several prospective and useful application sectors. The active functionalities of lignin promote its use as a valuable material to be adopted in the composite and nanocomposites arenas, being useful and suitable for consideration both for the synthesis of matrices and as a nanofiller. The aim of this review is to summarize, after a brief introduction on the need for alternative green solutions to petroleum-based plastics, the synthesis methods for bio-based and/or biodegradable thermoplastic and thermosetting nanocomposites, along with the application of lignin nanoparticles in all green polymeric matrices, thus generating responsiveness towards the sustainable use of this valuable product in the environment.

Preparation and Properties of Superhydrophobic ZnO Nanorod-based Nanocomposite on the Surface of Stainless Steel Mesh

Preparation and Properties of Superhydrophobic ZnO Nanorod-based Nanocomposite on the Surface of Stainless Steel Mesh

Preparation and Characterization of Silk Fibroin-PANI Nanocomposites and Their Application for Electrophysiological Signals Recording

Wearable dry electrodes are required for long-term biopotential recordings, but their availability is limited. The diagnosis of coronary heart disease is possible with ambulatory electrocardiography (ECG). For ambulatory ECG sensing, on-skin electrodes are used by conformably contacting the skin’s moving and arbitrary formed surface. However, the low skin-adhesion of electrodes restricts their use in ambulatory ECG sensing for an extended period of time. Here, it was possible to create extremely skin-adhesive and washable on-skin electrodes by developing a new composite of Poly aniline (PANI) and silk fibroin (SF). Self-adhesive property of silk fibroin - PANI electrodes was achieved by coating with silk/Ca2+ adhesive layers. These electrodes were applied to the skin to capture high-quality ECG readings for the detection of cardiac real status in order to show how they can be used to detect precise and dependable signals. Silk fibroin - PANI electrodes showed an excellent performance for ECG signals recording over different physiological states.

Green Copolymers and Nanocomposites from Myrcene and Limonene Using Algerian Nano-Clay as Nano-Reinforcing Filler.

In this work, we report a new facile method for the preparation of myrcene-limonene copolymers and nanocomposites using a Lewis acid as a catalyst (AlCl3) and organo-modified clay as a nano-reinforcing filler. The copolymer (myr-co-lim) was prepared by cationic copolymerization using AlCl3 as a catalyst. The structure of the obtained copolymer is studied and confirmed by Fourier Transform Infrared spectroscopy, Nuclear Magnetic Resonance spectroscopy, and Differential Scanning Calorimetry. By improving the dispersion of the matrix polymer in sheets of the organoclay, Maghnite-CTA+ (Mag-CTA+), an Algerian natural organophilic clay, was used to preparenanocomposites of linear copolymer (myr-co-lim). In order to identify and assess their structural, morphological, and thermal properties, the effect of the organoclay, used in varyingamounts (1, 4, 7, and 10% by weight), and the preparation process were investigated. The Mag-CTA+ is an organophylic montmorillonite silicate clay prepared through a direct exchange process in which they were used as green nano-reinforcing filler. The X-ray diffraction of the resulting nanocomposites revealed a considerable alteration in the interlayer spacing of Mag-CTA+. As a result, interlayer expansion and myr-co-lim exfoliation between layers of Mag-CTA+ were observed. Thermogravimetric analysis provided information on the synthesized nanocomposites' thermal properties. Fourier transform infrared spectroscopy and scanning electronic microscopy, respectively, were used to determine the structure and morphology of the produced nanocomposites (myr-co-lim/Mag). The intercalation of myr-co-lim in the Mag-CTA+ sheets has been supported by the results, and the optimum amount of organoclay needed to create a nanocomposite with high thermal stability is 10% by weight. Finally, a new method for the preparation of copolymer and nanocomposites from myrcene and limonene in a short reaction time was developed.

Preparation of graphene-carbon nanotube macroscopic body nanocomposite and its energy storage performance

In order to solve the problem of agglomeration and stacking between carbon nanotube (CNT) and graphene, achieve their uniform distribution and give full play to their good energy storage performance, a reduced graphene oxide (RGO)-CNT macroscopic body nanocomposite with a three-dimensional (3D) network structure was prepared in one step in this paper, which was carried out by a series of efficient bonding reactions between carboxylated CNT and graphene oxide in a hydrothermal environment. After being cut and pressed, the obtained macroscopic body composite could be directly assembled into the electrochemical supercapacitors for electrochemical performance testing. The obtained samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, Raman spectroscopy and N2 absorption and desorption. The research results show that the obtained RGO-CNT macroscopic body composite has an obvious 3D network structure and shows an excellent electrical conductivity. Its electrochemical discharge specific capacitance can be up to 157.05 F·g−1 in organic electrolyte, which is significantly higher than those of RGO or CNT. Moreover, the composite has a distinguished cycle performance.

Preparation, structure and photocatalytic activity of nanocomposites based on cerium oxide

Mesoporous CeO2 and MgO powders and nanocomposites based on them were synthesized by the method of self-propagating high-temperature synthesis, and the mutual influence of magnesium oxide and cerium oxide on the crystal structure, microstructure, and morphology of the obtained materials was studied. It has been established that CeO2 is formed on the surface of magnesium oxide, while the developed surface of the material is preserved. It has been established, that the sizes of CeO2 crystallites in the composition of nanocomposites change insignificantly and range from 6.5 to 7.4 nm, while the values of the specific surface area and average pore diameter of the studied samples depend on the composition and vary in the ranges of 19–41 m2/g and 11.9‒19 nm, respectively. The highest efficiency of photodegradation of dyes of acid telon blue and direct bright blue is observed for samples of MgO–CeO2 (30 mol.%) and MgO–CeO2 (50 mol.%) ‒ 98.5 and 92.5 %, respectively, taking into account the effect of direct photolytic decomposition under the influence of ultraviolet radiation.

A Review on Pulsed Laser Preparation of Nanocomposites in Liquids and Their Applications in Photocatalysis

The purpose of photocatalysis is to realize the conversion between solar energy and chemical energy, and it is essential to develop a high-performance photocatalyst under visible-light irradiation. The conventional methods for photocatalyst preparation are mainly wet chemical routes, and abundant yields can be obtained. However, the products are not neat and accompanied by chemical groups and impurities, which are not beneficial for the enhancement of photocatalytic performance. In recent years, as a powerful tool for nanomaterial fabrication, pulsed laser heating in a liquid medium has been utilized to prepare a variety of nanocomposites. Products with synergistic effects and high crystallinity can be rapidly prepared under pulsed laser selective heating, which is beneficial for obtaining more effective photocatalytic performance. In this review, the typical characteristics of pulsed laser heating in liquids and their prepared nanocomposites for photocatalytic applications are summarized. This review not only highlights the innovative works of pulsed-laser-prepared nanocomposites in liquids for photocatalysis but also briefly introduces the specific challenges and prospects of this field.

Low‐dielectric and low‐temperature curable fluorinated nano carbon/polyimide composites with 6‐aminoquinoline for end capping

AbstractOne challenge in the high‐performance dielectric material of polyimide (PI) is to obtain the excellent comprehensive properties at low curing temperature for advanced IC package. In this work, 6‐aminoquinoline (AQL) is introduced through covalent bonds for end capping to obtain a low‐temperature curable PI at first. The results demonstrate that with very limited introduce (2.76%) of AQL, the imidization index could reach as high as 1.01 at 200°C. Then, fluorinated nano carbon (FC) is further introduced resulting in the fluorinated nano carbon/polyimide (FCPI) composites, which effectively reduces the dielectric constant (1 wt%, 2.75 @ 1 MHz). Besides, the as‐prepared FCPIs also possess excellent thermal property of which FCPI‐0.3 exhibited the 5% weight loss temperature of 540°C and the glass transition temperature is also as high as 385°C. Furthermore, the tensile strength of the film is 127 MPa, the elongation at break is around 15.82%, and the Youngs' modulus is about 3.10 GPa proving the superior mechanical property. As a result, the successful preparation of the FCPI nanocomposites not only possess low‐temperature curing and low‐dielectric performance but also exhibit excellent thermal and mechanical properties, which shows a wide range of application prospects in the field of microelectronics for the advanced electronic package.

Multifunctional role of tannic acid in improving the mechanical, thermal and antimicrobial properties of natural rubber-molybdenum disulfide nanocomposites

Natural rubber is the only biosynthesized rubber and the most prominent of all the elastomers. Insertion of nanofillers into natural rubber matrix has received much research interest because of the enhanced mechanical, thermal, electrical, antibacterial, etc. properties of the final natural rubber nanocomposite. Molybdenum disulfide (MoS2), an important member in transition metal dichalcogenides (TMD) is having excellent optical, thermal, mechanical, electronic and antibacterial properties. The inherent properties of this novel filler was exploited through the preparation of natural rubber-MoS2 nanocomposites via latex dipping method in which tannic acid (TA), naturally occurring macromolecule was used as an exfoliating agent for MoS2. MoS2:TA dispersions were prepared in 1:2, 1:4 and 1:6 ratios by mechanical stirring followed by sonication method for analyzing the optimum amount of exfoliating agent for the preparation of NR-MoS2 nanocomposite. MoS2:TA in 1:4 ratio was found to be the optimum loading for the NR nanocomposite preparation with improved mechanical, thermal and antibacterial properties. The enhanced properties of the NR composites could be attributed to the synergistic effect of both MoS2 and TA. The current study shows the role of TA in tuning the properties of NR/MoS2 nanocomposites that enable their potential utilization in various biomedical applications.

Nanopriming-mediated memory imprints reduce salt toxicity in wheat seedlings by modulating physiobiochemical attributes

BackgroundAround the globe, salinity is one of the serious environmental stresses which negatively affect rapid seed germination, uniform seedling establishment and plant developments restricting sustainable agricultural productivity. In recent years, the concepts of sustainable agriculture and cleaner production strategy have emphasized the introduction of greener agrochemicals using biocompatible and natural sources to maximize crop yield with minimum ecotoxicological effects. Over the last decade, the emergence of nanotechnology as a forefront of interdisciplinary science has introduced nanomaterials as fast-acting plant growth-promoting agents.ResultsHerein, we report the preparation of nanocomposite using chitosan and green tea (CS-GTE NC) as an ecofriendly nanopriming agent to elicit salt stress tolerance through priming imprints. The CS-GTE NC-primed (0.02, 0.04 and 0.06%), hydroprimed and non-primed (control) wheat seeds were germinated under normal and salt stress (150 mM NaCl) conditions. The seedlings developed from aforesaid seeds were used for physiological, biochemical and germination studies. The priming treatments increased protein contents (10–12%), photosynthetic pigments (Chl a (4–6%), Chl b (34–36%), Total Chl (7–14%) and upregulated the machinery of antioxidants (CAT (26–42%), POD (22–43%)) in wheat seedlings under stress conditions. It also reduced MDA contents (65–75%) and regulated ROS production resulting in improved membrane stability. The priming-mediated alterations in biochemical attributes resulted in improved final germination (20–22%), vigor (4–11%) and germination index (6–13%) under both conditions. It reduced mean germination time significantly, establishing the stress-insulating role of the nanocomposite. The improvement of germination parameters validated the stimulation of priming memory in composite-treated seeds.ConclusionPre-treatment of seeds with nanocomposite enables them to counter salinity at the seedling development stage by means of priming memory warranting sustainable plant growth and high crop productivity.

Effect of the nanoparticles on the morphology and mechanical performance of thermally blown 3D printed HIPS foams

AbstractCellular polymer nanocomposites can combine high mechanical performance with low density. However, the manufacturing of porous nanocomposites into complex shapes can represent a challenge. Therefore, this article deals with the preparation, characterization, and 3D printing of porous nanocomposites. The filaments were extruded from the polymer nanocomposite filled by thermal chemical blowing agent, and then processed by 3D printing into the required shapes. In‐situ and post‐treatment foaming strategies were investigated and compared. The nanoparticles (NPs) significantly affected the processing, structure, thermal and mechanical properties of polymeric foams. The NPs, serving as a nucleating agent, allowed preparation of smaller pores and led to finer and more homogeneous foams. At the same time, they reinforced foam walls and thus improved mechanical properties. Moreover, NPs catalyzed decomposition of the blowing agent grains at lower temperature which brought about faster and more efficient foaming. This study showed the straightforward approach to prepare mechanically robust lightweight 3D printed materials.