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Washingtonia is a palm tree that enriched with lignocellulosic biomass, which provided it with the potentiality for various applications. In this study, different biomass from Washingtonia plant, i...

Conocarpus is a buttonwood plant enriched with lignocellulosic biomass, which has high potential for various applications. In this study, different biomasses of the Conocarpus plant, such as, leaf fibers (CP–L), branches (CP–B) and trunk (CP–T), were examined collectively through characterization techniques. The chemical composition analysis showed that CP–T fibers have a higher cellulose content than CPL and CP–B fibers. Elementary analysis also detected versatile elements based on minerals such as Mg, Si, P, S, Cl, K and Ca in fiber with a high ash content. Based on the morphological analysis, the CP–T fiber with compact and striated characteristics can contribute more effectively to the reinforcement of composite materials. In addition, the particle size of the fibers increased with increasing crystallinity, which depends on the source of the fibers, being smaller in those obtained from leaves and greater in those obtained from the trunk. This finding showed that the size of the fiber is highly correlated with the stiffness of the fiber structure. In addition, all fibers regardless of their source have great thermal stability, with a high onset degradation temperature of 273.9–316.2 °C. In conclusion, Conocarpus biomass fibers, due to its advantageous properties, have a potential to be used as a bio-filler in polymer composites.

In this paper, we have studied the feasibility of developing an Ethyl acetate sensor as a biomarker for early detection of lung cancer in the form of a chemical sensor. For this we report the effect of Ni and Cu doping on the electrochemical characteristics of the SnO2 nanomaterial synthesized by sol-gel method. Formation of composite nanomaterial of undoped/doped SnO2 was confirmed by structural, morphological and elemental characterization and used as matrix for ethyl acetate (EA) chemical sensor in the form of screen-printed electrode (SPE). Conventional electrochemical techniques such as cyclic voltammetry (CV), scan rate studies and impedance spectroscopic studies were conducted for several EA concentration from 1 to 20 ppb prepared in phosphate buffer solution (PBS). CV results shows a well-defined oxidation and reduction peak at different potential with different doping. The estimated sensitivity values for pristine SnO2 is $0.3\mu \text{A}$ /ppb, for NiSnO2 is $2.3~\mu \text{A}$ /ppb and for CuSnO2 is $4.8~\mu \text{A}$ /ppb when estimated over the wider range from 1ppb to 20ppb. Selectivity study was also conducted that showed selective response to EA.

Cu-doped ZnO nanoparticles were used in the form of a screen-printed electrode on a prefabricated gold-plated electrode for electrochemically determining the concentration of nanomolar myoglobin (Mb), a cardiac biomarker. Initially, Cu-doped ZnO nanoparticles were synthesised through the sol gel method by using three Cu-doping concentrations (varying number of Cu atoms). Then, the synthesised material was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, and field emission secondary electron microscopy. Analysis revealed a mixed phase of ZnO and CuO, whereas the vibration band in the range of 650-700 cm -1 indicated metal oxide formation. Morphological observation showed uniform-sized spherical particles of approximately 15-20 nm (as nanoparticles) that were evenly distributed, which were also confirmed based on the average particle size estimated using XRD data. The developed electrodes were tested for biomarker concentration from 3 to 15 nM based on cyclic voltammogram and impedance spectroscopic curves, where the redox potential/current/charge transfer resistance changed linearly with Mb and dopant (Cu) concentration. The sensitivity was estimated as 2.13-10.14~μAnM -1 cm -2 with dopant concentration of approximately 0.46 nM as the limit of detection.

The objective of current work is to evaluate the density, void content, water absorption, thickness swelling and thermal expansion of non-woven bamboo mat (B)/ woven kenaf mat (K)/nanoclay/epoxy hybrid nanocomposites. The natural fibers based hybrid nanocomposites were prepared by incorporation of montmorillonite (MMT), halloysite nanotube (HNT) and organically modified montmorillonite (OMMT) at 1 wt.% loading, through hand lay-up technique. Water absorption was investigated by soaking the samples with distilled water at room temperature until saturation point and the thickness swelling was also measured as per standard. Thermomechanical analyser (TMA) was used to study the dimensional stability caused by temperature variation. Addition of nanoclay increase the density, reduced the void content and suppress water uptake in all hybrid nanocomposites. B/K/OMMT hybrid nanocomposites exhibit better dimensional stability with regards to water absorptions and thermal expansion as compare to B/K/MMT and B/K/HNT. The improvement can be attributed by the uniformly dispersed and strong interfacial adhesion bonding between the OMMT and epoxy matrix. The develop nanocomposites in this work can be utilized for building and automotive application which required high dimensional stability property.

We demonstrate the preparation of nanostructures cobalt oxide/reduced graphene oxide (Co3O4/rGO) nanocomposites by a simple one-step cost-effective hydrothermal technique for possible electrode materials in supercapacitor application. The X-ray diffraction patterns were employed to confirm the nanocomposite crystal system of Co3O4/rGO by demonstrating the existence of normal cubic spinel structure of Co3O4 in the matrix of Co3O4/rGO nanocomposite. FTIR and FT-Raman studies manifested the structural behaviour and quality of prepared Co3O4/rGO nanocomposite. The optical properties of the nanocomposite Co3O4/rGO have been investigated by UV absorption spectra. The SEM/TEM images showed that the Co3O4 nanoparticles in the Co3O4/rGO nanocomposites were covered over the surface of the rGO sheets. The electrical properties were analyzed in terms of real and imaginary permittivity, dielectric loss and AC conductivity. The electrocatalytic activities of synthesized Co3O4/rGO nanocomposites were determined by cyclic voltammetry and charge-discharge cycle to evaluate the supercapacitive performance. The specific capacitance of 754 Fg-1 was recorded for Co3O4/rGO nanocomposite based electrode in three electrode cell system. The electrode material exhibited an acceptable capability and excellent long-term cyclic stability by maintaining 96% after 1000 continuous cycles. These results showed that the prepared sample could be an ideal candidate for high-energy application as electrode materials. The synthesized Co3O4/rGO nanocomposite is a versatile material and can be used in various application such as fuel cells, electrochemical sensors, gas sensors, solar cells, and photocatalysis.

In this study date palm stem fibers (DPF)/epoxy composites at different loading (40, 50 and 60 wt.%) were fabricated and their tensile, impact and morphological properties are characterized. The interfacial bonding in tensile fractured samples of composites was examined by scanning electron microscopy (SEM). Tensile and impact results revealed that increase in DPF loading until 50% improved the mechanical strength, modulus, impact strength and elongation at break with respect to pure epoxy resin. Tensile strength, modulus, impact strength and elongation at break of pure epoxy resin increases from 20.5 to 25.7657 MPa, 0.5123 to 1.546 GPa, 45.81 to 98.71 J/m and 0.91 to 1.412% respectively while, energy absorption decreases drastically from 50 to 32% with the incorporation of DPF filler. SEM microstructure displayed good interfacial bonding in 50% DPF epoxy however the addition of more DPF loading reduces the interfacial strength due to poor wettability. Overall test results declared that 50% DPF loading is ideal to enhance tensile, impact strengths and morphological properties of epoxy. Keywords: Date palm stem fiber, Epoxy resin, Polymer composites, Tensile properties, Impact strength, Morphological properties

The dimensional stability and dynamic mechanical properties on bamboo (non woven mat)/kenaf (woven mat) hybrid composites was carried out in this study. The hybridization effect of bamboo (B) and kenaf (K) fibers at different weight ratio were studied at B:K:70:30, and B:K:30:70 while maintaining total fiber loading of 40% by weight. The coefficient of thermal expansion (CTE) and dynamic mechanical properties of composites were analyzed by thermomechanical anlayzer (TMA), and dynamic mechanical analyzer (DMA), respectively. Positive hybridization effects were observed on B:K:50:50 hybrid composite with lowest CTE and highest dynamic mechanical properties among all composites. The dimensional stability were strongly influence by the fiber orientation where all composites shows prominent expansion in the transverse fibers direction but relatively low expansion in longitudinal fibers direction. Dynamic mechanical properties in term of complex modulus (E*), storage modulus (E′), loss modulus (E″), Tan delta and Cole-Cole plot were studied. DMA results reveal that B:K:50:50 hybrid composite possess the highest complex modulus due to the strong fiber/matrix interfacial bonding which supported by the coefficient of effectiveness and Cole-Cole plot. Hence, it is concluded that 50:50 weight ratio of bamboo and kenaf fibers is the optimum mixing ratio to enhance both dimensional and dynamic mechanical properties of hybrid composites, and it can be utilized for automotive or building materials applications which demand high dimensional stability and dynamic mechanical properties.

Cured epoxy resins pretense a constraint for variety of advanced applications due to its notably poor thermal and dynamic (viscoelastic) properties, hence required to minimize their properties prior to their usage. The aim of the present study is to evaluate the effect of nano oil palm empty fruit bunch (OPEFB) fibers at different loadings (1%, 3% and 5%) on the dynamic mechanical properties through dynamic mechanical analysis (DMA) in terms of storage modulus E′, loss modulus E″ and glass transition temperature (Tg) of epoxy composites. Results explored that dynamic properties of the epoxy composites get improved remarkably by the incorporation of nano OPEFB to epoxy composites, while 3% loading displays marked decrease in damping factor with relative to pure epoxy composites and the rest. Overall we perceived that the 3% loading of nano OPEFB filler is the best and optimal to enhance dynamic mechanical properties and to modify the damping factor of the epoxy composites resulting in most promising light weight and thermally stable composite structural materials. Keywords: Oil palm fibers, Epoxy matrix, Nanocomposites, Glass transition temperature, Dynamic mechanical properties, Damping factor

The aim of the present study is to improve the flexural, thermal stability and dynamic mechanical properties of epoxy composites by reinforcing date palm fibres (DPF) at different loading (40%, 50% and 60% by wt.) and to evaluate the best loading through hand lay-up technique. Three point bending dynamic properties in terms of storage modulus (E′), loss modulus (E″) damping factor, Cole–Cole plot and thermal properties were analyzed by dynamic mechanical and thermogravimetric analyser, respectively. Flexural test results show that loading of 50% DPF increases both the flexural strength and modulus of pure epoxy composites from 26.15 MPa to 32.64 MPa and 2.26 GPa to 3.28 GPa, respectively. TGA results revealed that reinforcement of DPF in epoxy composites also improves the thermal stability and residual content. The residual content of epoxy (9.58%), 40% DPF/epoxy (12.51%), 50% DPF/epoxy (19.8%) and for 60% DPF/epoxy composites (15.2%) was noted, revealing that 50% DPF/epoxy composites confers the best result. Incorporation of DPF into epoxy also improves the E′ and E″ but 50% DPF show more remarkable improvement compared to 40% and 60% DPF loading. Moreover, damping factor decreases considerably by the reinforcement of DPF and are found lowest for 50% DPF/epoxy composites among all composites. Drawn Cole–Cole plot also suggests the existence of certain heterogeneity in DPF/epoxy composites compared to homogenous nature of epoxy composites. We concluded that 50% DPF loading is the ideal loading to enhanced flexural, thermal stability and dynamic properties of epoxy composites. Keywords: Date palm fibres, Epoxy composites, Flexural strength, Thermal stability, Dynamic mechanical properties, Damping factor, Cole–Cole plot

The capability of functional logic operations is highly intriguing, but far from being realized owing to limited recognition element (RE) and complex readout signals, which limit their applications. In this contribution, for a visual colorimetric sensor for melamine (MEL) we described the construction of two- and three-input AND logic gate by exploiting the intrinsic peroxidase (POD)-like activity of CeO2 nanorods (NRs) (~23.04% Ce3+ fraction and aspect ratio (RTEM) of 3.85 ± 0.18) as RE at acidic pH (4.5). Further ATP piloted catalytic tuning of POD-like activity in CeO2 NRs employed for a functional logic gate-controlled MEL sensing at neutral pH (7.4). AND logic circuit operated MEL sensing record colorimetric response time of 15 minutes to produce blue color proportionate to MEL concentration. The fabricated nanozyme (CeO2)-based logic gate sensor probe for MEL at pH 4.5 showed a linear response from 0.004 nM to 1.56 nM with a limit of detection (LOD) of 4 pM, while translation from acidic to neutral pH (at 7.4) sensor exhibited linear response ranging from 0.2 nM to 3.12 nM with a LOD value of 17 pM. Through CeO2 POD-like nanozyme behavior under acidic and neutral pH, the fabricated logic gate sensor showed high affinity for MEL, generating prominent visual output with picomolar sensitivity, good reproducibility, and stability with relative standard deviation (RSD) &lt, 1% and 2%, respectively. A feasibility study in real samples (raw milk and milk powder) showed good recoveries with negligible matrix effect, an anti-interference experiment revealed sensor selectivity, highlighting robust sensor practical utility. With the merits of high sensitivity, specificity, low cost, and simplified sample processing, the developed logic-controlled colorimetric MEL sensing platform with appropriate modifications can be recognized as a potent methodology for on-site analysis of various food adulterants and related applications.

In this study, three types of nanoclay [halloysite nanotube (HNT), montmorillonite (MMT) and organically modified MMT (OMMT)] were incorporated into bamboo/kenaf (B/K) reinforced epoxy hybrid composites to compare their thermo-oxidative (TOD) stability and flammability properties. B/K (50 : 50) hybrid nanocomposites were fabricated by adding 1% loading (by weight) nanoclay through a hand lay-up technique. Wide angle X-ray scattering (WAXS) and field emission scanning electron microscopy (FESEM) were used to study the morphology of the nanoclay–epoxy mixture. The TOD stability of the hybrid nanocomposites was studied with a thermogravimetry analyzer (TGA) under oxygen atmosphere. The flammability properties were evaluated using the Underwriters Laboratories 94 horizontal burning test (UL-94HB), limiting oxygen index (LOI), cone calorimetry and smoke density test. The morphological study reveals that MMT/epoxy and HNT/epoxy are highly agglomerated while OMMT/epoxy reveals a more uniform distribution morphology. The obtained results reveal that B/K/HNT shows better TOD stability below 300 °C, but B/K/MMT and B/K/OMMT show high residue content and decomposition temperatures above 300 °C. The flame retardancy of the hybrid nanocomposites improved with the loading of all types of nanoclay, but B/K/OMMT shows higher flame retardancy than B/K/MMT and B/K/HNT hybrid nanocomposites. Hybrid nanocomposites show improvement in flame properties in terms of peak heat release rate (pHRR), total heat release, fire growth rate index (FIGRA) and maximum average rate of heat emission (MARHE) and smoke growth rate index (SMOGRA) indicators. The findings from this work can be utilized to prepare high-performance fire retardant natural fiber reinforced epoxy hybrid composites for automotive and construction applications to save human lives.

Herein, we present the synthesis, characterization and optical ammonia gas sensing of pure and Sn-doped vanadium oxide (V2O5) nanoparticles prepared by the sol-gel process. The V2O5 nanoparticles were doped with Sn concentrations of 2 wt%–6 wt%, and characterized using X-ray diffraction, atomic force microscopy, UV–vis spectroscopy and photoluminescence spectroscopy which confirmed the orthorhombic crystal structure. The crystalline size was found to decrease with enhancing the doping concentrations of Sn. The lattice-strain and crystalline size with the peak-broadening of pure and Sn doped V2O5 nanoparticles were analyzed by William-Hall (W-H) method and size-strain plot. The UV–vis absorption showed a decrease in the energy band gap (3.27 eV–3.07 eV) with an increase in the Sn doping concentration. The Sn-doped V2O5 nanoparticles were used to detect ammonia gas (5–50 ppm) through photoluminescence based detection method. Interestingly, it was observed that the optical response for the 2 wt% Sn doped V2O5 nanoparticles was maximum (77.84%) towards 50 ppm ammonia compared to other V2O5nanoparticles based samples.

Bamboo-/kenaf-reinforced epoxy hybrid composites were prepared by hand layup method. The aim of this study is to look into the hybridization effect of bamboo and kenaf fibers at different ratios on thermal and thermo-oxidative (TOD) stabilities of hybrid composites. Three types of hybrid composites were fabricated with different mass ratios of bamboo fiber mat (B) to kenaf fiber mat (K), namely B/K 70:30, B/K 50:50 and B/K 70:30 while maintaining total fiber loading of 40% by mass. The thermal stability and thermo-oxidative (TOD) stability were analyzed by thermogravimetric analyzer. Differential scanning calorimetry (DSC) was used to investigate the oxidation onset temperature (OOT) of all the composites. The results reveal that bamboo composite shows higher thermal stability than kenaf composite in both inert and oxidative atmospheres. An increase in bamboo fibers mass ratio in the hybrid composite improved the thermal and TOD stability. The thermal and TOD stabilities of the hybrid composites follow the sequence of B/K 70: 30 > B/K 50:50 > B/K 30:70. Pure epoxy composite recorded the highest OOT at 197.50 °C. The results show that the addition of natural fiber in the epoxy matrix has significantly reduced the OOT compared to the pure epoxy. Data obtained from this work will help us to fabricate a sustainable and biodegradable component for automotive or building materials.

Silane treated pineapple leaf fibre (PALF) and kenaf fibre were analyzed by Thermogravimetric analysis (TGA) that indicated the treated hybrid composite showed better thermal stability as compared to untreated hybrid composites. Dynamic mechanical analysis was carried out to evaluate the storage modulus (E′), loss modulus (E″), and tan delta as a function of temperature. Storage modulus of treated hybrid composites displayed highest storage and loss modulus as in comparison of untreated hybrid composites. The peak heights of tan α were highest in treated hybrid composites. Cole-Cole analysis was also carried out to understand the phase behaviour of the composite samples. Thermal mechanical analysis was used to study mechanical stability of hybrid composites in the presence of temperature. The effect of different fibre ratios in hybridization on density, void content, water absorption (WA), thickness swelling (TS) of PALF/KF hybrid composites were also analyzed. Treated hybrid composites were not very affective to improve the flammability of PALF/KF hybrid composites. The overall results showed that treated PALF/KF/phenolic hybrid composites improved the thermal and dynamic mechanical properties over untreated PALF/KF hybrid composites.

The aim of this work to investigate the effect of glass fiber (GF) on the thermal properties of sugar palm (SP)/thermoplastic polyurethane (TPU) hybrid composites. Sugar palm/glass fiber hybrid composites at the different weight fraction of 0/40, 10/30, 20/20 and 30/10 were prepared by using melt-mixing compounding followed by hot pressing machine. Thermal properties of hybrid composites carried out by using Dynamic mechanical analyzer (DMA) and thermo-gravimetric analyzer (TGA). The storage modulus (E′), loss modulus (E″) and damping factor (tan δ) were evaluated as a function of different relative sugar palm/glass fiber weight fraction. Also, the peak height was investigated for tan δ curves. At higher glass fiber loading exhibited the highest storage and loss modulus while the lowest damping factor was observed for higher sugar palm fiber loading. Thermogravimetric analysis (TGA) demonstrated that the amount of residue decreased as the glass fiber loading decreased. Overall, the hybridization of glass fiber with sugar palm/TPU composites enhances the thermal properties of the hybrid composites for automotive applications .

The sensitive and selective electrochemical detection of picric acid (PA), a toxic, harmful environmental pollutant and an explosive, using different morphologies of cuprous oxide (Cu2O) is reported. The different Cu2O morphologies, synthesized by a hydrothermal method for 8 h, 10 h, and 12 h, were characterized using various techniques to confirm their morphological, optical, compositional, and structural properties. Sensors, fabricated in the form of screen-printed electrodes using these different morphologies of Cu2O, were used to study the electrochemical sensing capabilities of the nanomaterials for PA (7.8 μ M to 10.0 mM). Cyclic voltammetry studies revealed a distinct change in the redox peak current as a function of PA concentration, which was further confirmed by electrochemical impedance spectroscopy studies, as the charge-transfer resistance increased with an increase in PA concentration. Scan rate studies showed that the electrochemical sensing of PA is a surface-controlled process, involving rapid electron transfer. Among the different morphologies, Cu2O synthesized for 8 h showed a reproducible and reliable sensitivity of 130.4 μA mM−1 cm−2 with a limit of detection of 39 μM and good linearity over a wide range of PA concentrations. Interference studies with other phenolic compounds revealed the presence of distinct peaks corresponding to PA, indicating that the fabricated sensor shows specificity and selectivity for PA.

Recently, growing environmental impact associated with production, disposal and recycling of synthetic fibre based polymer composites triggers the development of ecofriendly composite for various applications such as automotive, marine, chemical, Infrastructure, sporting goods etc. Among many natural fibres like kenaf, jute, oil palm, cotton, flax, banana and hemp, sisal are gaining attention as they are abundantly available, cheaper, eco-friendly and possess remarkable and satisfactory mechanical properties to hemp, banana and jute. Sisal fibre will play a key role to fabricate a varied range of structural and non-structural industrial products with different polymer matrix. This review article deals the mechanical properties of sisal fibre and the several factors influencing the mechanical properties of its polymer composites, such as fibre loadings, fibre length, fibre architecture, chemical treatments and hybridization by incorporating different natural/synthetic fibre/fillers or additive, according to the application and strength requirements. Attempt also been made to investigate the effect of water absorption, chemical concentration, exposure time, filler weight% and individual fibre loading % in the hybrid configuration on the mechanical properties. Overall present review article was designed to explore, highlights and gathered the previous reported studies directing the mechanical properties of sisal fibre and its polymer composites to provide a perfect source of data and literature for doing future research to reveal it as construction and building materials like synthetic fibres.

Background: Phenolic resins received greater attention from academic researchers and made prestigious status among all thermoset resins. Several effective attempts have made to explore different synthesis processes of producing phenolic in more useful and advanced way. Since the date of innovation, huge varieties of biocomposites and composites products have been produced for various applications. Methods: Among all types of Phenolic resin related applications, Phenolic resin molding compounds have been used for highest utility products due to better mechanical strength, resistance, long-term reliability and cost effectiveness. Results: Currently, modified phenolic resins are broadly used in the fabrication of synthetic/natural fiber reinforced composites in order to replace metals and ceramics on industrial level owing to its superior mechanical, thermal and electrical properties. This review article is intended to present an overview on the phenolic chemistry, curing process, structure, synthesis and its properties. Conclusion: The present review article also aims to cover the reported research works on modified phenolic, and bio-phenolic resins, and their diverse industrial applications to support the ongoing research and development in green sustainable commercial products.

In a quest for developing new material with performance of dye sensitized solar cells (DSSC) a non-metallic doping i.e., of nitrogen was carried out to commercial TiO2 nanoparticle using simple, facile and sustainable mechanochemistry method. Melamine was used as source of nitrogen and different weight percentages (10, 30, 50, 70 and 90%), mixed with TiO2 mechanically in a ball mill for 12 h at an speed of 500 rotations per minute followed by annealing at 550 °C for 2 h under constant N2 flow. The post nitrogen doping structural analysis indicated anatase phase of TiO2.The morphological observations by transmission electron microscopy did not show change due to melamine and particle size remains less than 30 nm. N-doping resulted in an increased wavelength of peak absorption from 334 nm to about 350 nm and shifting of absorption edge from UV (~ 400 nm) to visible region (~ 500 nm) resulting in the reduction of the band gap from 3.14 to 2.43 eV which is supported by XPS and Tauc plot analysis. The functional analysis reveals amide bond at higher melamine concentration. The DSSC characteristics were measured with source-meter coupled with simulated light source which shows a significant increase of cell efficiency from 26 with 10% of melamine to that of 86 with 90% melamine. The increase in efficiency was linear with increasing nitrogen doping concentration. The study suggested that melamine can be used as a suitable N-dopant source for improved photoconversion properties that can help engineer to develop a device with enhanced performance.

This paper reports the synthesis, characterization and fabrication of enzyme-less glucose sensor based on iron oxide (α-Fe2O3) nanoparticles synthesized by facile hydrothermal process. The synthesized nanoparticles were characterized by various techniques to understand the morphologies, composition and scattering properties. The morphological and structural studies confirmed the successful formation of α-Fe2O3 nanoparticles in large quantity which exhibiting well-crystallinity and rhombohedral crystal structures. The fabricated enzyme-less glucose sensor based on α-Fe2O3 nanoparticles revealed high sensitivity of 30.89 μA/mM cm2 with a fast response time (5 sec). The fabricated glucose sensor exhibited high reproducibility and its electrochemical response found to be linear over a wide concentration range of glucose from 1 to 10 mM with coefficient of regression (R) = 0.9981.

In recent times, much attention has been paid to explore economic and highly active precious metal free electrocatalysts for energy conversion and storage systems due to the expensiveness of Pt-based catalysts. Here we developed a mesoporous core-shell like nanospheres composed of a metallic cobalt oxide core wrapped with a polypyrrole nanoshell (PPy/Co3O4) for methanol electrooxidation. The performance of the core-shell PPy/Co3O4 nanospheres as anodic catalyst material was measured in 1 M KOH electrolyte and the results obtained demonstrated that the hybrid possesses high catalytic activity in terms of current density and onset voltage. The core-shell PPy/Co3O4 delivers an oxidation current density of ∼111 mA/cm2 at 0.5 V with superior stability long run stability. The observed electrocatalytic performance of the porous PPy/Co3O4 nanospheres is attributed to the integrative effects of both Co-species and layered carbon shell and presence of exceptionally numerous mesopores. Results show evidence that the earth abundant PPy/Co3O4 provide a potential electrode material for methanol electrooxidation with a satisfactory reaction activity.

The performance polymer electrolyte membrane fuel cells (PEMFCs) and alkaline fuel cells (AFCs) relays on the kinetics of oxygen reduction reaction at the cathode side of the fuel cell. Efficient electrocatalyst with high activity and selectivity are of great importance to achieve ORR with four-electron reaction pathway. Targeting robust and cost-effective alternatives to noble metal electrocatalysts, we skillfully fabricated nitrogen doped carbon supported cobalt phosphide (N-C@CoP) nanorod arrays as an earth abundant material for catalyzing ORR. The obtained N-C@CoP composite with relatively high surface area and favorable mesoporous features exhibits intriguing ORR catalytic performances in alkaline conditions due to ease mass diffusion, fast charge transport, and abundance of electroactive sites as a result of doped nitrogen moieties. In addition, the composite catalyst exhibits remarkable durability through an 80,000 s test compared to benchmark Pt catalyst, demonstrating excellent structure stability. The enhanced ORR performances of N-C@CoP catalyst suggest it as a potential non-Pt containing electrocatalyst for efficient ORR.

In this study, microcrystalline cellulose (MCC) was extracted from roselle fiber through acid hydrolysis treatment and its properties were compared with those of commercially available MCC. The physicochemical and morphological characteristics, elemental composition, size distribution, crystallinity and thermal properties of the obtained MCC were analyzed in this work. Fourier transform infrared spectroscopy (FTIR) analysis provided clear evidence that the characteristic peak of lignin was absent in the spectrum of the MCC prepared from roselle fiber. Rough surface and slight aggregation of MCC were observed by scanning electron microscopy (SEM). Energy dispersive X-ray (EDX) analysis showed that pure MCC with small quantities of residues and impurities was obtained, with a similar elemental composition to that of commercial MCC. A mean diameter of approximately 44.28μm was measured for MCC by using a particle size analyzer (PSA). X-ray diffraction (XRD) showed the crystallinity increased from 63% in roselle pulp to 78% in roselle MCC, the latter having a slightly higher crystallinity than that of commercial MCC (74%). TGA and DSC results indicated that the roselle MCC had better thermal stability than the roselle pulp, whereas it had poorer thermal stability in comparison with commercial MCC. Thus, the isolated MCC from roselle fibers will be going to use as reinforcing element in green composites and may be a precursor for future roselle derived nanocellulose, and thus a promising subject in nanocomposite research.

Oxygen reduction reaction (ORR) catalysts are the heart of eco-friendly energy resources particularly low temperature fuel cells. Although valuable efforts have been devoted to synthesize high performance catalysts for ORR, considerable challenges are extremely desirable in the development of energy technologies. Herein, we report a simple self-polymerization method to build a thin film of dopamine along the tubular nanostructures of multi-walled carbon nanotubes (CNT) in a weak alkaline solution. The dopamine@CNT hybrid (denoted as DA@CNT) reveals an enhanced electrocatalytic activity towards ORR with highly positive onset potential and cathodic current as a result of their outstanding features of longitudinal mesoporous structure, high surface area, and ornamentation of DA layers with nitrogen moieties, which enable fast electron transport and fully exposed electroactive sites. Impressively, the as-obtained hybrid afford remarkable electrochemical durability for prolonged test time of 60,000 s compared to benchmark Pt/C (20 wt%) catalyst. Furthermore, the developed DA@CNT electrode was successfully applied to access the quality of antiviral drug named Valacyclovir (VCR). The DA@CNT electrode shows enhanced sensing performance in terms of large linear range (3–75 nM), low limit of detection (2.55 nM) than CNT based electrode, indicating the effectiveness of the DA coating. Interestingly, the synergetic effect of nanostructured DA and CNT can significantly boost the electronic configuration and exposure level of active species for ORR and biomolecule recognition. Therefore, the existing carbon-based porous electrocatalyst may find numerous translational applications as attractive alternative to noble metals in polymer electrolyte membrane fuel cells and quality control assessment of pharmaceutical and therapeutic drugs.

The current study presents about the effect of cellulose nanofibers (CNFs) filler on the thermal and dynamic mechanical analysis (DMA) of epoxy composites as a function of temperature. In this study hand lay-up method was used to fabricate CNF reinforced Epoxy nanocomposites with CNF loading of 0.5%, 0.75%, and 1% into epoxy resin. The obtained thermal and DMA results illustrates that thermal stability, char content, storage modulus (E'), loss modulus (E") and glass transition temperature (Tg) increases for all CNF/epoxy nanocomposites compared to the pure epoxy. Thermal results revealed that 0.75% offers superior resistance or stability towards heat compared to its counterparts. In addition, 0.75% CNF/epoxy nanocomposites confers highest value of storage modulus as compared to 0.5% and 1% filler loading. Hence, it is concluded that 0.75% CNFs loading is the minimal to enhance both thermal and dynamic mechanical properties of the epoxy composites and can be utilized for advance material applications where thermal stability along with renewability are prime requirements.

The aim of present study was to investigate the thermal properties and flame retardancy behavior of flame retardant (FR) epoxy nanocomposites from chemically treated (bromine water and tin chloride) oil palm empty fruit bunch (OPEFB) nano filler at different filler loading (1, 3, 5%). Thermal properties were evaluated through thermogravimetry analyzer, derivative thermogravimetry and differential scanning calorimetry. FR properties of nanocomposites are evaluated through UL-94 vertical burning test and limiting oxygen index (LOI). The functional group analysis of all composites was made by FTIR spectroscopy. Thermal analysis shows that degradation temperature of epoxy composites shifts from 370 to 410 °C and char yield also increases for 3% loading. Furthermore LOI value of 29% and UL-94 rating of V-0 with no flame dripping and cotton ignition, revealed that 3% oil palm nano filler filled epoxy nanocomposites display satisfactory flame retardancy. The superior flame retardancy of epoxy nanocomposites are attributed to the chemical reactions occurred in the gaseous phases and the profound synergistic flame retardation effect of tin with bromine in the treated nano OPEFB filler. All the epoxy nanocomposites displayed almost similar FTIR spectra with the characteristics metal-halogen bond supporting the synergism. Homogeneous dispersion of 3% oil palm nano filler act as highly effective combustion chain terminating agent compared with 1 and 5% nano OPEFB/epoxy nanocomposites.

In this study, the effect of different polypropylene (PP) matrices (homopolymer (HPP), impact copolymer (ICP), and recycled polypropylene (rPP)) on the mechanical, morphological, and thermal properties of date palm fiber (DPF)-reinforced PP composites was investigated. The DPFs were treated with an alkali solution, and composites were fabricated with different DPF loadings (5, 10, and 15 wt %) and lengths (less than 2 mm and 8&ndash, 12 mm). It was found that the tensile properties of the DPF/ICP and DPF/rPP composites were similar to those of the DPF/HPP composites. The addition of fiber to the matrix reduced its tensile strength but increased the modulus. The alkali treatment improved the compatibility between the fibers and the matrix by removing hemicellulose and other impurities. Fourier transform infrared spectroscopy confirmed hemicellulose removal. The morphology of the alkali-treated fractured tensile specimen revealed improved adhesion and less fiber pull out. Differential scanning calorimetry revealed that the alkali treatment enhanced the crystallinity index. Thermogravimetric analysis showed that the addition of DPFs into the PP matrix reduced the thermal stability of the composite. However, the thermal stability of the treated fiber-reinforced rPP and ICP composites was similar to that of the DPF/HPP composite. Hence, rPP can be used as an alternative to HPP with DPFs.

The present study deals with the fabrication of epoxy composites reinforced with 50 wt% of date palm leaf sheath (G), palm tree trunk (L), fruit bunch stalk (AA), and leaf stalk (A) as filler by the hand lay-up technique. The developed composites were characterized and compared in terms of mechanical, physical and morphological properties. Mechanical tests revealed that the addition of AA improves tensile (20.60&ndash, 40.12 MPa), impact strength (45.71&ndash, 99.45 J/m), flexural strength (32.11&ndash, 110.16 MPa) and density (1.13&ndash, 1.90 g/cm3). The water absorption and thickness swelling values observed in this study were higher for AA/epoxy composite, revealing its higher cellulosic content, compared to the other composite materials. The examination of fiber pull-out, matrix cracks, and fiber dislocations in the microstructure and fractured surface morphology of the developed materials confirmed the trends for mechanical properties. Overall, from results analysis it can be concluded that reinforcing epoxy matrix with AA filler effectively improves the properties of the developed composite materials. Thus, date palm fruit bunch stalk filler might be considered as a sustainable and green promising reinforcing material similarly to other natural fibers and can be used for diverse commercial, structural, and nonstructural applications requiring high mechanical resistance.

Current work aims to study the mechanical and dynamical mechanical properties of non-woven bamboo (B)/woven kenaf (K)/epoxy (E) hybrid composites filled with nanoclay. The nanoclay-filled BK/E hybrid composites were prepared by dispersing 1 wt.% nanoclay (organically-modified montmorillonite (MMT, OMMT), montmorillonite (MMT), and halloysite nanotube (HNT)) with high shear speed homogenizer followed by hand lay-up fabrication technique. The effect of adding nanoclay on the tensile, flexural, and impact properties of the hybrid nanocomposites were studied. Fractography of tensile-fractured sample of hybrid composites was studied by field emission scanning electron microscope. The dynamic mechanical analyzer was used to study the viscoelastic properties of the hybrid nanocomposites. BK/E-OMMT exhibit enhanced mechanical properties compared to the other hybrid nanocomposites, with tensile, flexural, and impact strength values of 55.82 MPa, 105 MPa, and 65.68 J/m, respectively. Statistical analysis and grouping information were performed by one-way ANOVA (analysis of variance) and Tukey method, and it corroborates that the mechanical properties of the nanoclay-filled hybrid nanocomposites are statistically significant. The storage modulus of the hybrid nanocomposites was improved by 98.4%, 41.5%, and 21.7% with the addition of OMMT, MMT, and HNT, respectively. Morphology of the tensile fracture BK/E-OMMT composites shows that lesser voids, microcracks and fibers pull out due to strong fiber&ndash, matrix adhesion compared to other hybrid composites. Hence, the OMMT-filled BK/E hybrid nanocomposites can be utilized for load-bearing structure applications, such as floor panels and seatbacks, whereby lightweight and high strength are the main requirements.

Date palm fibre is a sustainable biomass as well as an alternative biomaterial for producing cellulose nanocrystal (CNC), which was extensively used in different application fields by attributing to high surface reactivity during fabrication process. In this work, combined sulfuric/acetic acid hydrolysis of 10/90, 20/80 and 30/70 (wt %/wt %) were employed to extract DPCNC-I, DPCNC-II and DPCNC-III, respectively from date palm fibre. From structural examination, rod-like crystal particle feature was observed for each nanoparticle sample. In terms of physicochemistry, pure cellulose component was revealed by DPCNC-II and DPCNC-III. The crystallinity degree had also been enhanced for each nanoparticle, particularly for DPCNC-III with the remarkable crystallinity of 84.2 %. For thermal behavior, DPCNC-III exhibited the greatest endurance towards heat degradation in among those CNC samples. In summary, date palm CNC could be a potential filling agent applied in various industrial fields.

Energy cost comparison between MSF, MED and SWRO has been conducted. In order to investigate energy consumption differences when combined with a simple cycle Oil-Fired Power Plant (OFPP) or a Combined Cycle Power Plant (CCPP), Yanbu Ph.3 and Ras Al-Khair Ph.1 power and water cogeneration projects are considered as practical heat and mass balance references. With the net power production of 2708.5 MW and the total water production of 124.54 MIGD, the fuel energy differences due to desalination are compared. By calculating the fuel energy requirement for desalination from a cogeneration cycle itself, some controversial issues including evaluating electricity and steam could be avoided. Results show that the required fuel energies for desalination are less by 11–49% when combined with CCPP than with OFPP, owing to the higher efficiency of the combined cycle. Thermal desalination benefits more greatly from the combined cycle's higher efficiency due to a lowered steam value. While SWRO shows a better fuel energy efficiency for most of the studied regime, high Performance Ratio (PR) MEDs combined with CCPP could be a similar energy efficient option if PR is 16.5–19.3, compared to SWRO with CCPP.

Kenaf fibers have been extensively explored from the past few decades in polymer composites industries owing to its extensive adaptations, excellent properties together with its comparable mechanical properties to traditional glass fibers polymer composites. The combustibility or lowered flame retardancy hampered the diverse applications of kenaf fibers reinforced polymer composites, as it affects the mechanical strength and stiffness of composites during fire. Current review article intended to be a comprehensive source of published literature involving the flame retardants (FRs), types and applications of FRs and the fabrication of kenaf fibers reinforced polymer composites. This article will also provide a perfect data on the recent development of the FR kenaf fibers polymer composites with different FRs and explored its structural and semi-structural industrial application for performing further research in this topic. Copyright © 2016 John Wiley & Sons, Ltd.

Dynamic mechanical analysis (DMA) is a versatile technique that complements the information provided by the more traditional thermal analysis techniques such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermal mechanical analysis (TMA). The dynamic parameters such as storage modulus (E′), loss modulus (E″), and damping factor (Tan δ) are temperature dependent and provide information about interfacial bonding between the reinforced fibre and polymer matrix of composite material. The dynamic parameters were ominously influenced by the increase in fibre length and loading but not in a geometric progression. Dynamic loading conditions are frequently stumble in civil infrastructure systems due to sound, winds, earthquakes, ocean waves and live loads. Vibration damping parameters shows prime importance for structural applications in order to enhance the reliability, performance, buildings comfort and in the alleviation of bridges hazards. DMA also predicts the effects of time and temperature on polymer sealants viscoelastic performance under different environments. Present review article designed to be a comprehensive source of reported literature involving dynamic mechanical properties of natural fibre reinforced polymer composites, hybrid and nano composites and its applications. This review article will provides a perfect data to explore its industrial application primarily as cheaper construction and building materials for doing further research in this topic.

Olive fiber is a sustainable material as well as alternative biomass for extraction of nanocrystalline cellulose (NCC), which has been widely applied in various industries. In the present study, ONC-I, ONC-II, and ONC-III were extracted from olive stem fiber at different hydrolysis reaction times of 30 min, 45 min, and 60 min, respectively. The nanoparticle size was found gradually reducing from ONC-I (11.35 nm width, 168.28 nm length) to ONC-III (6.92 nm width, 124.16 nm length) due to the disintegration of cellulose fibrils. ONC-II and ONC-III possessed highly pure cellulose compartments and enhanced crystals structure. This study also showed that rigidity increased from ONC-I to ONC-II. ONC-III showed the highest crystallinity of 83.1 %, endowing it as a potentially reliable load-bearing agent. Moreover, ONC-III exhibited highest stable heat resistance among the chemically-isolated nanocellulose. We concluded that olive NCC could be promising materials for a variety of industrial applications in various fields.

Herein, MoS2-ZnO heterostructure nanorods were hydrothermally synthesized and characterized in detail using several compositional, optical, and morphological techniques. The comprehensive characterizations show that the synthesized MoS2/ZnO heterostructure nanorods were composed of wurtzite hexagonal phase of ZnO and rhombohedral phase of MoS2. The synthesized MoS2/ZnO heterostructure nanorods were used as a potent photocatalyst for the decomposition of methylene blue (MB) dye under natural sunlight. The prepared MoS2/ZnO heterostructure nanorods exhibited ~97% removal of MB in the reaction time of 20 min with the catalyst amount of 0.15 g/L. The kinetic study revealed that the photocatalytic removal of MB was found to be in accordance with pseudo first-order reaction kinetics with an obtained rate constant of 0.16262 min&minus, 1. The tremendous photocatalytic performance of MoS2-ZnO heterostructure nanorods could be accredited to an effective charge transportation and inhibition in the recombination of photo-excited charge carriers at an interfacial heterojunction. The contribution of active species towards the decomposition of MB using MoS2-ZnO heterostructure nanorods was confirmed from scavenger study and terephthalic acid fluorescence technique.

The versatile characteristic of epoxy and its diversity made it suitable for different industrial applications such as laminated circuit board, electronic component encapsulations, surface coatings, potting, fiber reinforcement, and adhesives. However, the pervasive applications in many high-performance field limited the epoxy use because of their delamination, low impact resistance, inherent brittleness, and fracture toughness behavior. The limitations of epoxy can be overcome by incorporation and modification before their industrial applications. Currently, modified epoxy resins are extensively used in fabrication of natural fiber-reinforced composites and in making its different industrial products because of their superior mechanical, thermal, and electrical properties. Present review article designed to be a comprehensive source of recent literature on epoxy structure, synthesis, modified epoxy, bio-epoxy resin, and its applications. This review article also aims to cover the recent advances in natural fiber-based epoxy composites and nanocomposites research study, including manufacturing techniques and their different industrial applications.

This study aims to gain insight into the influence of environmental effects on the colour, biodegradability, oxidation stability, thermal stability and complex modulus of bamboo/kenaf fiber reinforced epoxy hybrid composites. The composites were prepared by the hand lay-up technique, with a fixed loading of 40% fibers for all the composites. Three types of hybrid composites were prepared with different mixing ratios of bamboo fibers (B) to kenaf fibers (K): (i) 30:70, (ii) 50:50, and (iii) 70:30. Kenaf/epoxy and bamboo/epoxy composites, as well as pure epoxy, were also prepared for comparison purposes. The kenaf, bamboo and hybrid composites were exposed to UV radiation at elevated temperature and humidity, for a total exposure period of 156 h. The colour changes occurring during the weathering process were assessed by colorimetric analysis. The effects of soil burial on the developed composites were also studied for different time periods of 3, 6 and 12 months. Thermal properties, in terms of oxidation stability, thermal stability and dynamic mechanical properties, were determined by differential scanning calorimetry, thermogravimetric analysis and dynamic mechanical analysis, respectively. The results obtained from colorimetric analysis indicated that increasing the bamboo fiber loading in the formulation of hybrid composites induced higher total colour changes. The biodegradability of hybrid composites at higher kenaf loading increased as the soil burial period was longer. Overall, soil burial has led to more pronounced degradation, as compared to accelerated weathering, in terms of oxidation stability, thermal stability and dynamic mechanical properties. The findings of this work reveal that the hybrid composite formulation B:K:50:50 presents a balance of resistance to environmental effects, while maintaining the biodegradability characteristic, which makes it suitable for its use as a potential biocomposite material for structural applications.

Present study, deals about isolation and characterization of cellulose nanofibers (CNFs) from the Northern Bleached Softwood Kraft (NBSK) pulp, fabrication by hand lay-up technique and characterization of fabricated epoxy nanocomposites at different filler loadings (0.5%, 0.75%, 1% by wt.). The effect of CNFs loading on mechanical (tensile, impact and flexural), morphological (scanning electron microscope and transmission electron microscope) and structural (XRD and FTIR) properties of epoxy composites were investigated. FTIR analysis confirms the introduction of CNFs into the epoxy matrix while no considerable change in the crystallinity and diffraction peaks of epoxy composites were observed by the XRD patterns. Additions of CNFs considerably enhance the mechanical properties of epoxy composites but a remarkable improvement is observed for 0.75% CNFs as compared to the rest epoxy nanocomposites. In addition, the electron micrographs revealed the perfect distribution and dispersion of CNFs in the epoxy matrix for the 0.75% CNFs/epoxy nanocomposites, while the existence of voids and agglomerations were observed beyond 0.75% CNFs filler loadings. Overall results analysis clearly revealed that the 0.75% CNFs filler loading is best and effective with respect to rest to enhance the mechanical and structural properties of the epoxy composites.