Nanocellulose-graphene hybrid composites for high-performance uses have been the focus of recent research. In contrast to graphene, which has great conductivity and mechanical strength, nanocellulose possesses special qualities like renewability and biocompatibility but lacks electrical conductivity. Since graphene-nanocellulose has such promising features, efforts to make flexible electronic composites employing them have accelerated. However, the environmental impacts are needed to be addressed prior to the applications of these hybrid composites. This review article explores environmental aspects for nanocellulose-graphene hybrid composites because of their sustainability, which is a major step in the right direction. The article also emphasizes how these composites have the potential to transform several industries and open the door to a more environmentally friendly future. This paper explores into the most recent developments in nanocellulose-graphene hybrid composites, highlighting its environmental benefits and adaptability. These composites offer remarkable performance by combining the strength and conductivity of graphene with the mechanical, electrical, and thermal capabilities of nanocellulose.
Nanocellulose, obtained from natural cellulose, has attracted considerable interest for its distinctive properties and wide-ranging potential applications. Studies suggest that nanocellulose improves the thermal, mechanical, and barrier properties of conventional cellulose. This review investigates the production, properties, approach, and application of nanocellulose from various sources in agriculture. The main role play of cellulose-nanocomposite is discussed as a seed coating agent to improve seed dispersal, germination, protection against fungi and insects, plant growth promoter, adsorption of targeted pollutants, providing water and nutrient retention, and other advantages. As a nobility, we included all mechanical, chemical, and static culture approaches to the production procedure of nanocellulose and its application as a nanocarrier in soil, including the unique properties of nanocellulose, such as its high surface area, inherent hydrophilicity, and ease of surface modification. Here, methods such as melt compounding, solution casting, and in situ polymerization were evaluated to incorporate nanoparticles into cellulose materials and produce nanocellulose and cellulose-nanocomposites with improved strength, stability, water resistance, and reduced gas permeability. The commercialization faces challenges such as high production costs, scalability issues, and the need for more research on environmental impacts and plant interactions. Despite these hurdles, this field is promising, with ongoing advancements likely to yield new and improved agricultural materials. This review thoroughly examines the innovative application of nanocellulose in slow and controlled-release fertilizers and pesticides, to transform nutrient management, boost crop productivity, and minimize the environmental impact.
Environmental issues have resulted in the forming of sustainable materials, including natural fiber-reinforced PLA composites; nonetheless, this composite has low water resistance, resulting in poor composite performance. This research aims to investigate the impact of adding a small amount of graphene nanoplatelets (GNP) on the water absorption (WA) characteristic of bamboo/kenaf-reinforced PLA hybrid composites. The physical behavior and water resistance of the composites, as well as the mechanical performance and surface after 14 days of immersion, were comprehensively investigated. The study discovered that adding a small amount of GNP to composites increased their density, with the highest density of 1.6326 g/cm3 (1GBK), and altered the chemical composition's transmittance. Also, the inclusion of GNP increases the composite's crystallinity. Furthermore, the addition of GNP resulted in a decline in WA, with the lowest absorption being 4.95 % (1GBK), which is supported by the composites' increased contact angle. After 14 days of immersion, the GNP-filled composites were superior to the BK sample in terms of mechanical properties. When fibers absorb water, their surface degrades because the fibers are swelling, but GNP functions as a water barrier, preventing surface degradation due to inhibition of fiber swelling. This study highlights the potential for a straightforward and economical method to address the limited water resistance of bamboo/kenaf-reinforced PLA hybrid composites, a limitation that hinders their widespread use.
Nanolignin is a biomacromolecule nanomaterial obtained from lignin, a natural plant polymer. It has attracted considerable attention as a potential nanofiller for polymer composites owing to its remarkable properties, such as biodegradability, antioxidant activity, and high specific surface area. However, the development of biological macromolecule nano lignin-based polymer composites faces several challenges, mainly due to the complex structure and poor chemical compatibility of lignin with most polymers. A comprehensive summary of the functionalization strategies and synthesis techniques for nanolignin is provided in this article. The morphological, structural, and thermal characterization of nanolignin is also reviewed. Furthermore, this review summarizes the recent progress of nanolignin and its composites prepared using various polymers, such as polyvinyl alcohol, poly (methyl methacrylate), polylactic acid, phenol formaldehyde, and natural rubber. This study concludes by outlining the possible uses of nanolignin-reinforced polymer composites and the potential opportunities and disadvantages of using nanolignin as a reinforcement in polymer composites for several value-added applications.
This study focuses on the fabrication and electrical characterization of a polymer composite based on nano-sized varistor powder. The polymer composite was fabricated by the melt-blending method. The developed nano-composite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FeSEM), and energy-dispersive X-ray spectroscopy (EDAX). The XRD pattern revealed the crystallinity of the composite. The XRD study also showed the presence of secondary phases due to the substitution of zinc by other cations, such as bismuth and manganese. The TEM picture of the sample revealed the distribution of the spherical, nano-sized, filler particles throughout the matrix, which were in the 10-50 nm range with an average of approximately 11 nm. The presence of a bismuth-rich phase and a ZnO matrix phase in the ZnO-based varistor powder was confirmed by FeSEM images and EDX spectra. From the current-voltage curves, the non-linear coefficient of the varistor polymer composite with 70 wt% of nano filler was 3.57, and its electrical resistivity after the onset point was 861 KΩ. The non-linear coefficient was 1.11 in the sample with 100 wt% polymer content. Thus, it was concluded that the composites established a better electrical non-linearity at higher filler amounts due to the nano-metric structure and closer particle linkages.
Graphene and its derivative materials present high potential towards medical and biological applications, including drug delivery and bioimaging, due to their exceptional properties such as thermal conductivity and high specific surface area. The main focus of this work is to review the current development of graphene materials and the derivatives for biocompatible, bioimaging and drug delivery applications. Also, the synthesis methods with variation of graphene nanocomposites and the functionalisation will be further explained. For the graphene approaches, chemical vapour deposition (CVD) is the best-known technique to make high-quality graphene sheet by growth route with mass production. By considering the organic graphene nanocomposites, the biocompatibility and cytotoxic effects against graphene nanocomposites were evaluated for biomedical employments such as high quality bioimaging and effective drug delivery for cancer treatments. For example, graphene oxide incorporated with PEG and loaded with SN 38 for camptothecin analolgue as anticancer drug and revealed high cytotoxicity has an effect of 1000 times better effect than CPT in HCT-116 cells. Their drug delivery ability for both in-vivo and in-vitro applications compared to the controlled drugs such as doxorubicin (DOX) will be discussed accordingly. The graphene and its deriavatives possess some intriguing properties, which will lead to drug delivery due to strong biocompatibility and cyctotoxic effect towards biomedicine applications.
Graphene-based adsorbents have attracted wide interests as effective adsorbents for heavy metals removal from the environment. Due to their excellent electrical, mechanical, optical and transport properties, graphene and its derivatives such as graphene oxide (GO) have found various applications. However, in many applications, surface modification is necessary as pristine graphene/GO may be ineffective in some specific applications such as adsorption of heavy metal ions. Consequently, the modification of graphene/GO using various metals and non-metals is an ongoing research effort in the carbon-material realm. The use of organic materials represents an economical and environmentally friendly approach in modifying GO for environmental applications such as heavy metal adsorption. This review discusses the applications of organo-functionalized GO composites for the adsorption of heavy metals. The aspects reviewed include the commonly used organic materials for modifying GO, the performance of the modified composites in heavy metals adsorption, effects of operational parameters, adsorption mechanisms and kinetic, as well as the stability of the adsorbents. Despite the significant research efforts on GO modification, many aspects such as the interaction between the functional groups and the heavy metal ions, and the quantitative effect of the functional groups are yet to be fully understood. The review, therefore, offers some perspectives on the future research needs.
Eco-friendly nanotechnology-enabled biopolymers are one of the novel concepts of packaging materials to substitute traditional synthetic polymers and their composites. This article succinctly reviews the recent developments of introducing additional functionalities to biopolymers using metal and metal oxide nanoparticles. The functionality of metal nanoparticles such as silver, zinc oxide, titanium dioxide, copper oxide, gold, and magnesium oxide, as food packaging materials were discussed. The addition of nanoparticles in biopolymers improves mechanical properties, gas barrier properties, durability, temperature stability, moisture stability, antimicrobial activity, antioxidant property, and UV absorbance and can prevent the presence of ethylene and oxygen, hence extending the shelf life of foodstuffs. Other than this, the functional activity of these biopolymer composite films helps them to act like smart or intelligent packaging. The selection of metal nanoparticles, particle migration, toxicological effect, and potential future scope in the food packaging industry are also reviewed.
Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe3O4/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions.
Calcium silicate (CaSiO3, CS) ceramic composites reinforced with graphene nanoplatelets (GNP) were prepared using hot isostatic pressing (HIP) at 1150°C. Quantitative microstructural analysis suggests that GNP play a role in grain size and is responsible for the improved densification. Raman spectroscopy and scanning electron microscopy showed that GNP survived the harsh processing conditions of the selected HIP processing parameters. The uniform distribution of 1 wt.% GNP in the CS matrix, high densification and fine CS grain size help to improve the fracture toughness by ∼130%, hardness by ∼30% and brittleness index by ∼40% as compared to the CS matrix without GNP. The toughening mechanisms, such as crack bridging, pull-out, branching and deflection induced by GNP are observed and discussed. The GNP/CS composites exhibit good apatite-forming ability in the simulated body fluid (SBF). Our results indicate that the addition of GNP decreased pH value in SBF. Effect of addition of GNP on early adhesion and proliferation of human osteoblast cells (hFOB) was measured in vitro. The GNP/CS composites showed good biocompatibility and promoted cell viability and cell proliferation. The results indicated that the cell viability and proliferation are affected by time and concentration of GNP in the CS matrix.
This paper presents the green synthesis of silver nanoparticles (Ag NPs) in aqueous medium. This method was performed by reducing AgNO(3) in different stirring times of reaction at a moderate temperature using green agents, chitosan (Cts) and polyethylene glycol (PEG). In this work, silver nitrate (AgNO(3)) was used as the silver precursor while Cts and PEG were used as the solid support and polymeric stabilizer. The properties of Ag/Cts/PEG nanocomposites (NCs) were studied under different stirring times of reaction. The developed Ag/Cts/PEG NCs were then characterized by the ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.
Polypyrrole (PPy) and polypyrrole-carboxylic functionalized multi wall carbon nanotube composites (PPy/f-MWCNT) were synthesized by in situ chemical oxidative polymerization of pyrrole on the carbon nanotubes (CNTs). The structure of the resulting complex nanotubes was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The effects of f-MWCNT concentration on the electrical properties of the resulting composites were studied at temperatures between 100 K and 300 K. The Hall mobility and Hall coefficient of PPy and PPy/f-MWCNT composite samples with different concentrations of f-MWCNT were measured using the van der Pauw technique. The mobility decreased slightly with increasing temperature, while the conductivity was dominated by the gradually increasing carrier density.
Magnetic nanoparticles (MNPs) were synthesized by the coprecipitation of Fe(2+) and Fe(3+) iron salts in alkali media. MNPs were coated by chitosan (CS) to produce CS-MNPs. Streptomycin (Strep) was loaded onto the surface of CS-MNPs to form a Strep-CS-MNP nanocomposite. MNPs, CS-MNPs, and the nanocomposites were subsequently characterized using X-ray diffraction and were evaluated for their antibacterial activity. The antimicrobial activity of the as-synthesized nanoparticles was evaluated using different Gram-positive and Gram-negative bacteria, as well as Mycobacterium tuberculosis. For the first time, it was found that the nanoparticles showed antimicrobial activities against the tested microorganisms (albeit with a more pronounced effect against Gram-negative than Gram-positive bacteria), and thus, should be further studied as a novel nano-antibiotic for numerous antimicrobial and antituberculosis applications. Moreover, since these nanoparticle bacteria fighters are magnetic, one can easily envision magnetic field direction of these nanoparticles to fight unwanted microorganism presence on demand. Due to the ability of magnetic nanoparticles to increase the sensitivity of imaging modalities (such as magnetic resonance imaging), these novel nanoparticles can also be used to diagnose the presence of such microorganisms. In summary, although requiring further investigation, this study introduces for the first time a new type of magnetic nanoparticle with microorganism theranostic properties as a potential tool to both diagnose and treat diverse microbial and tuberculosis infections.
A novel nano-bio composite polypyrrole (PPy)/kappa-carrageenan(KC) was fabricated and characterized for application as a cathode catalyst in a microbial fuel cell (MFC). High resolution SEM and TEM verified the bud-like shape and uniform distribution of the PPy in the KC matrix. X-ray diffraction (XRD) has approved the amorphous structure of the PPy/KC as well. The PPy/KC nano-bio composites were then studied as an electrode material, due to their oxygen reduction reaction (ORR) ability as the cathode catalyst in the MFC and the results were compared with platinum (Pt) as the most common cathode catalyst. The produced power density of the PPy/KC was 72.1 mW/m(2) while it was 46.8 mW/m(2) and 28.8 mW/m(2) for KC and PPy individually. The efficiency of the PPy/KC electrode system is slightly lower than a Pt electrode (79.9 mW/m(2)) but due to the high cost of Pt electrodes, the PPy/KC electrode system has potential to be an alternative electrode system for MFCs.
This paper provides a comprehensive analysis of the dielectric and physicochemical properties of the porous hydroxyapatite/cornstarch (HAp/Cs) composites in a new perspective. The porous composites have been characterized via SEM, FTIR, XRD and dielectric spectroscopy. The dielectric permittivity spectra were obtained in Ku-band (12.4-18.0 GHz) and it was correlated with the physicochemical properties of the porous HAp/Cs. Porous HAp/Cs composites exhibits low ε' and negative ε″, which influenced by the microstructural morphology, interaction between Hap and Cs, as well as crystalline features due to the various proportion of the HAp/Cs. The physicochemical effect of the composites results in the dielectric polarization and energy loss. This phenomenon indicates the presence of the three obvious relaxation responses in the ε' spectrum (13.2-14.0, 15.2-16.0, and 16.6-17.4 GHz) and the negative behaviours in the ε″ spectrum. The relationships between physicochemical and dielectric properties of the porous composite facilitate the development of the non-destructive microwave evaluation test for the porous composite.
Nanocomposites of zinc oxide loaded on a zeolite (Zeolite/ZnO NCs) were prepared using co-precipitation method. The ratio effect of ZnO wt.% to the Zeolite on the antibacterial activities was investigated. Various techniques were used for the nanocomposite characterization, including UV-vis, FTIR, XRD, EDX, FESEM and TEM. XRD patterns showed that ZnO peak intensity increased while the intensities of Zeolite peaks decreased. TEM images indicated a good distribution of ZnO-NPs onto the Zeolite framework and the cubic structure of the zeolite was maintained. The average particle size of ZnO-nanoparticles loaded on the surface of the Zeolite was in the range of 1-10nm. Moreover, Zeolite/ZnO NCs showed noticeable antibacterial activities against the tested bacteria; Gram- positive and Gram- negative bacteria, under normal light. The efficiency of the antibacterial increased with increasing the wt.% from 3 to 8 of ZnO NPs, and it reached 87% against Escherichia coli E266.
This paper presents the fabrication of a highly sensitive and selective glucose sensor based on cuprous oxide/graphene nanocomposites-modified glassy carbon electrode (Cu2O/graphene/GCE). The Cu2O/graphene nanocomposites were synthesized based on a simple and straightforward chemical reduction process in alkaline aqueous solution using sodium carbonate as reductant. The size and shape of Cu2O nanoparticles on graphene sheets can be controlled by changing the amount of graphene oxide added during reaction. The electrochemical properties of Cu2O/graphene/GCE in 0.1M phosphate buffer solution were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. It was found that the pH, concentration of supporting electrolyte, and scan rate had very crucial effect on the sensitivity of prepared sensor towards glucose oxidation. At an applied potential of +0.50V, the Cu2O/graphene/GCE presented a high sensitivity of 1330.05μAmM(-1)cm(-2) and fast response (within 3s). The amperometric non-enzymatic glucose sensor developed had a linear relationship from 0.01mM to 3.0mM glucose and detection limit of 0.36μM. In the presence of ascorbic acid, uric acid, dopamine, chloride and citrate ion and other carbohydrates, the interferences were negligible. The proposed sensor was successfully applied for the determination of glucose concentration in real human blood samples.
A novel magnetic graphene oxide modified with chitosan (MGO-CTS) was synthesised as an adsorbent aimed to examine the simultaneous removal of mycotoxins. The composite was characterised by various procedures, namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and a scanning electron microscope (SEM). The adsorption evaluation was considered via pH effects, initial mycotoxin concentration, adsorption time and temperature. Adsorption isotherm data and kinetics experiments were acquired at the optimum pH 5 fit Freundlich isotherm as well as pseudo-second-order kinetic models. The thermodynamic results indicated that the adsorption of the mycotoxins was spontaneous, endothermic and favourable.
The utilization of nanocellulose has increasingly gained attentions from various research fields, especially the field of polymer nanocomposites owing to the growing environmental hazardous of petroleum based fiber products. Meanwhile, the searching of alternative cellulose sources from different plants has become the interests for producing nanocellulose with varying characterizations that expectedly suit in specific field of applications. In this content the long and strong bast fibers from plant species was gradually getting its remarkable position in the field of nanocellulose extraction and nanocomposites fabrications. This review article intended to present an overview of the chemical structure of cellulose, different types of nanocellulose, bast fibers compositions, structure, polylactic acid (PLA) and the most probable processing techniques on the developments of nanocellulose from different bast fibers especially jute, kenaf, hemp, flax, ramie and roselle and its nanocomposites. This article however more focused on the fabrication of PLA based nanocomposites due to its high firmness, biodegradability and sustainability properties in developed products towards the environment. Along with this it also explored a couple of issues to improve the processing techniques of bast fibers nanocellulose and its reinforcement in the PLA biopolymer as final products.
Graphene is a 2-dimensional nanomaterial with an atomic thickness has attracted a strong scientific interest owing to their remarkable optical, electronic, thermal, mechanical and electrochemical properties. Graphene-based materials particularly graphene oxide and reduced graphene oxide are widely utilized in various applications ranging from food industry, environmental monitoring and biomedical fields as well as in the development of various types of biosensing devices. The richness in oxygen functional groups in the materials serves as a catalysis for the development of biosensors/electrochemical biosensors which promotes for an attachment of biological recognition elements, surface functionalization and compatible with micro- and nano- bio-environment. In this review, the graphene-based materials application in electrochemical biosensors based on recent advancement (e.g; the surface modification and analytical performances) and the utilization of such biosensors to monitor the noncommunicable diseases are presented. The detection performances of the graphene-based electrochemical biosensors are in the range of ng/mL and have reached up to fg/mL in detecting the targets of NCDs with higher selectivity, sensitivity and stability with good reproducibility attributes. We have discussed the advances while addressing the very specific biomarkers for the NCDs detection. Challenges and possible future research directions for the NCDs detection based on graphene nanocomposite with other 2D nanomaterials are outlined.