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In the last two decades, there has been an incredible awareness on natural plant fiber composites due to their biodegradability, low weight, non-corrosiveness, and recyclability. Many studies have been attempted to improve the performance of the natural plant fiber composite since it has many applications in the engineering sectors. But the adaptation of natural plant fiber composite has some drawbacks such as water absorption, non-linearity in fiber dimensions, low interfacial adhesion between fiber-matrix, and less uniform strength of the fiber. Several studies have attempted to enhance the natural plant fiber composite properties by various fibers, matrix, fiber orientation, fiber treatment, fiber loading, fiber length, fillers, and other reinforcements. However, fiber’s hydrophilic character is inevitable and influences the composite performance. To overcome the drawback, fiber coating is a felicitous technique. Few researchers have performed the fiber (Sisal, Jute, Flax, Ramie, Bamboo) coating to enhance the composite properties of tensile strength, flexural strength, impact strength, water resistance, viscoelastic behavior, and electrical conductivity. Considering the importance of fiber coating (Dip, Spray, Electroless), the present study summarizes the fiber coating types, coating materials, and their composite performance.

In the last two decades, there has been an incredible awareness on natural plant fiber composites due to their biodegradability, low weight, noncorrosiveness, and recyclability. Many studies have been attempted to improve the performance of the natural plant fiber composite since it has many applications in the engineering sectors. But the adaptation of natural plant fiber composite has some drawbacks such as water absorption, nonlinearity in fiber dimensions, low interfacial adhesion between fiber-matrix, and less uniform strength of the fiber. Several studies have attempted to enhance the natural plant fiber composite properties by various fibers, matrix, fiber orientation, fiber treatment, fiber loading, fiber length, fillers, and other reinforcements. However, fiber's hydrophilic character is inevitable and influences the composite performance. To overcome the drawback, fiber coating is a felicitous technique. Few researchers have performed the fiber (Sisal, Jute, Flax, Ramie, Bamboo) coating to enhance the composite properties of tensile strength, flexural strength, impact strength, water resistance, viscoelastic behavior, and electrical conductivity. Considering the importance of fiber coating (Dip, Spray, Electroless), the present study summarizes the fiber coating types, coating materials, and their composite performance. [ABSTRACT FROM AUTHOR]

During last few decades, the hybrid composites emerged from natural fiber has brought incontestable advantages over synthetic materials. The environmental impact such as toxicity, nonbiodegradable garbage, and noise pollution has led to the identification of new class of fibers and also subsequent failure in critical stiffness and weight sensitivities of fiber-reinforced polymers has initiated magnification of mechanical toughness. In this present paper, fiber-reinforced composite materials are made with Camellia sinensis–Ananas comosus hybridized by glass fiber and epoxy resin matrix. The amalgamated laminates were forged by a compression molding process with the composition of 40% wt. of reinforcing fiber and 60% wt. of epoxy matrix in a constant proportion. A hydrophilic content present inside natural fibers are alkalized by 5% of NaOH to modify as hydrophobic nature for intensifying bonding between fiber and matrix. These hybridized fibers are mechanically, chemically, morphologically, and acoustically analyzed to meet the requirements of mechanical and sound proofing properties. The results shows that 25% wt. fraction of Camellia sinensis amalgamate with unidirectional fiber shows better average acoustical absorption coefficient (AAC) of 0.46 at 2000–6300 Hz frequency range and compared with existing material to establish the potential of using it in sound-proofing acoustical applications such as architectural acoustics, sound recording and reproduction room, noise barrier walls, loudspeaker design, etc.

Herein, a full spectrum-induced hybrid structure consisting of one-dimensional nickel titanate (NiTiO3) nanofibers (NFs) decorated by petal-like molybdenum disulfide (MoS2) particles was designed through a facile hydrothermal method. The key parameters for tailoring the morphology and chemical, surface, and interfacial properties of the heterostructure were identified for efficient and selective conversion of CO2 into valuable chemicals. Introducing MoS2 layers onto NiTiO3 NFs provided superior CO2 conversion with significantly higher yields. The optimized hybrid structure produced CO and CH4 yields of 130 and 55 μmol g−1 h−1, respectively, which are 3.8- and 3.6-times higher than those from pristine NiTiO3 nanofibers (34 and 15 μmol g−1 h−1, respectively) and 3.6- and 5.5-times higher than those from pristine MoS2 (37 and 10 μmol g−1 h−1, respectively). This improved performance was attributed to efficient absorption of a wider spectrum of light and efficient transfer of electrons across the heterojunction. Effective charge separation and reduced charge carrier recombination were confirmed by photoluminescence and impedance measurements. The performance may also be partly due to enhanced hydrophobicity of the hierarchical surfaces due to MoS2 growth. This strategy contributes to the rational design of perovskite-based photocatalysts for CO2 reduction.

During last few decades, the hybrid composites emerged from natural fiber has brought incontestable advantages over synthetic materials. The environmental impact such as toxicity, nonbiodegradable garbage, and noise pollution has led to the identification of new class of fibers and also subsequent failure in critical stiffness and weight sensitivities of fiber-reinforced polymers has initiated magnification of mechanical toughness. In this present paper, fiber-reinforced composite materials are made with Camellia sinensis–Ananas comosus hybridized by glass fiber and epoxy resin matrix. The amalgamated laminates were forged by a compression molding process with the composition of 40% wt. of reinforcing fiber and 60% wt. of epoxy matrix in a constant proportion. A hydrophilic content present inside natural fibers are alkalized by 5% of NaOH to modify as hydrophobic nature for intensifying bonding between fiber and matrix. These hybridized fibers are mechanically, chemically, morphologically, and acoustically analyzed to meet the requirements of mechanical and sound proofing properties. The results shows that 25% wt. fraction of Camellia sinensis amalgamate with unidirectional fiber shows better average acoustical absorption coefficient (AAC) of 0.46 at 2000–6300 Hz frequency range and compared with existing material to establish the potential of using it in sound-proofing acoustical applications such as architectural acoustics, sound recording and reproduction room, noise barrier walls, loudspeaker design, etc. [ABSTRACT FROM AUTHOR]

In this study, the prediction of the breakdown probability of a new batch of nanofluid (NF), namely exfoliated hexagonal boron nitride based NF is performed. Weibull two‐parameter model distribution function has been used to predict the AC breakdown voltage (ACBDV) probability percentage at 5, 10, 50 and 63.2% of failure. To verify the effect of ageing on the other allied properties like dielectric dissipation factor, resistivity, interfacial tension, acid number and thermal conductivity of the insulating NF, oxidative ageing test has been performed at three different ageing durations and compared with the existing mineral oil (MO). It is observed that the new batch of NF has the superior properties to be new age insulating oil compared to the MO. A significant enhancement in the ACBDV and thermal conductivity of the NF compared to MO is observed. Hydrophobic nature of the nanoparticle (NP) which has the minimum affinity towards the polar contamination hinders early ageing degradation in the NF. The enhancement in ACBDV of NF is due to the stimulated charge accumulation on the surface of the NP of the NF. The high aspect ratio of the exfoliated NP surface enhances the heat transfer capabilities in the NF. [ABSTRACT FROM AUTHOR]

In this work, the effect of two different diamine monomers, containing phosphine oxide, on thermal, mechanical and morphological properties of copolyimides and their hybrid materials was investigated. Gas separation properties of the synthesized copolyimides were also analysed. Two different diamine monomers with phosphine oxide were bis(3-aminophenyl) phenylphosphine oxide (BAPPO) and bis(3-aminophenoxy-4-phenyl) phenylphosphine oxide (m-BAPPO). In the synthesis of copolyimides 3,3’-diamino-diphenyl sulfone (DDS) was also used as the diamine, as well as 2,2’-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). Copolyimide films were prepared by thermal imidization. Hybrid materials containing 5 % SiO2 were synthesised further by sol-gel technique. The Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy (NMR) confirmed the expected structure. Dynamic mechanical analysis (DMA) demonstrated that m-BAPPO based copolyimides had lower glass transition temperatures (Tg) than BAPPO based copolyimides. m-BAPPO containing copolyimide without silica shifted the thermal decomposition temperature to a higher value. The moduli and strength values of BAPPO diamine containing copolyimide and its hybrid were higher than those of m-BAPPO containing materials. The contact angle measurements showed the hydrophobicity. Scanning electron microscope (SEM) analysis exhibited the silica particles dispersion in the copolyimides. These copolyimides may be used in the coating industry. The CO2 permeability and the permselectivity were the highest among the other values in this study, when m-BAPPO containing copolyimide in the absence of silica was used. The gas permeabilities obtained from this work were in this decreasing order: PCO2 > PO2 > PN2.

High surface area SiO 2 samples were synthesized by one-step hydrolysis and co-condensation at different pH (between 3.0 and 6.0) using tetraethyl orthosilicate as the Si source and formamide as the drying additive. The effects of the presence of H 2 O, formamide and NH 3 solution on the hydrophobic nature, textural properties and catalytic functionality of SiO 2 were investigated. The physico-chemical properties of the samples were measured by XRD, FTIR, SEM, TEM, N 2 -physisorption and NH 3 -TPD techniques. It was observed that the use of formamide led to the formation of strong Si-O-Si bonds and the samples possessed a high surface area (325–853 m 2 g −1 ), large pore size (42.5 Å) and large pore volume (0.875 cm 3 g −1 ). The characterization results also indicated that SiO 2 sample prepared in the absence of water at pH = 3 possessed fewer surface hydroxyl groups, leading the sample to have predominantly hydrophobic nature. An increase in water content in the SiO 2 precursor solutions resulted in an increase in the average particle size with a more hydrophilic nature. All synthesized SiO 2 samples were tested for partial oxidation of methanol at a temperature range of 200–400 °C. The sample synthesized at pH = 3 without water offer 90% conversion at 400 °C; however the SiO 2 sample synthesized with low water content (100 mmol) at pH = 4 offered the best selectivity (83%) to methyl formate and formaldehyde with moderate methanol conversion (72%). The SiO 2 sample prepared at pH = 6 with more water content offered less methanol conversion (60%) and low selectivity toward oxygenated products. It is evident that SiO 2 samples that possessed better textural properties and moderate hydrophobicity performed better in partial methanol oxidation. [ABSTRACT FROM AUTHOR]

Environmentally beneficial composites can be made by replacing synthetic fibers with various types of cellulosic fibers. Fibers from pine wood, coir, sisal, abaca, coir, etc. are all good candidates. The most important factor in finding good fiber reinforcement in the composites is the strength of adhesion between matrix polymer and fiber. Due to the presence of hydroxyl groups and other polar groups in various constituents of abaca, the moisture absorption is high, which leads to poor wettability and weak interfacial bonding between fibers and the more hydrophobic matrices. Therefore, it is necessary to impart a hydrophobic nature to the fibers by suitable chemical treatments in order to develop composites with better mechanical properties. In the present work, the effect of alkali treatment on the moisture absorption tendency of single abaca fiber was investigated. The results shown that the alkali treated fiber absorbs less moisture than the untreated raw fiber.

In this work, the effects of two different diamine monomers containing phosphine oxide on the thermal, mechanical and morphological properties of copolyimides and their hybrid materials were investigated. The gas separation properties of the synthesized copolyimides were also analyzed. The two different diamine monomers containing phosphine oxide were bis(3-aminophenyl] phenylphosphine oxide (BAPPO) and bis[4-(3-aminophenoxy)phenyl) phenylphosphine oxide (m-BAPPO). In the synthesis of the copolyimides, 3,3'-diaminodiphenyl sulfone (3,3'-DDS) was also used as the diamine, as well as 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). Copolyimide films were prepared by thermal imidization. Furthermore, hybrid materials containing 5 % SiO2 were synthesized by the sol-gel technique. Fourier--transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR) confirmed the expected structures. Dynamic mechanical analysis (DMA) demonstrated that the m-BAPPO-based copolyimides had lower glass transition temperatures (Tg) than the BAPPO-based ones. The thermal decomposition temperature of the m-BAPPO-containing copolyimide without silica was shifted to a higher value. The moduli and strength values of the BAPPO diamine-containing copolyimide and its hybrid were higher than those of the m-BAPPO-containing materials. Contact angle measurements showed their hydrophobicity. Scanning electron microscope (SEM) analysis showed the dispersion of the silica particles in the copolyimides. These copolyimides may be used in the coating industry. The CO2 permeability and the perm-selectivity were the highest, among the other values found in this study, when the m-BAPPO-containing copolyimide in the absence of silica was used. The gas permeabilities obtained from this work were in the decreasing order: ... [ABSTRACT FROM AUTHOR]

This study investigates the effect of landfill age on landfill leachate characteristics; two aspects are focused here. One is ultraviolet absorbance at 254 nm (UV254) property, as the discharge of landfill leachates to publically owned treatment works can cause interference with UV254 disinfection. The other is biorefractory organic nitrogen in leachates, as it can contribute to effluent nitrogen making it difficult to meet stringent effluent nitrogen regulations. To study variation in UV254-absorbing organic carbon and organic nitrogen, leachate samples ranging from cells with ages 2 to 30 y from a large landfill in Kentucky, were collected and fractionated on a basis of their molecular weight and chemical nature into humic acids, fulvic acids and a hydrophilic fraction. The effectiveness of long term landfilling and membrane treatment for organic matter and organic nitrogen removal was examined. Humic materials, which were the major UV254-absorbing substances, were mainly >1 kDa and they degraded significantly with landfill age. The hydrophilic organic fraction, which was the major contributor to organic nitrogen, was mainly <1 kDa and it became increasingly recalcitrant with landfill age. This study provides insight into the characteristics of the different leachate fractions with landfilling age that might aid the design of on-site leachate treatment techniques. [ABSTRACT FROM AUTHOR]

Abstract: Two catalysts, Ni/SBA-15 and Ni/MgO were prepared by wet impregnation technique with 5wt.% Ni loading in each catalyst. These were tested for nitrobenzene hydrogenation to aniline reaction under vapor phase at atmospheric pressure. Ni/MgO suffered a huge loss in the activity (conversion) during time on stream study even though the Ni dispersion is larger compared to that in SBA-15 supported catalyst. TPR studies of used catalysts confirm coking of the catalysts. The superior catalytic activity in terms of conversion and selectivity during time on stream operation exhibited by Ni/SBA-15 catalyst is due to the hydrophobic nature of this catalyst (resistant to water generated during the reaction) and the effect of coking is not significant. [Copyright &y& Elsevier]

Herein, a full spectrum-induced hybrid structure consisting of one-dimensional nickel titanate (NiTiO 3 ) nanofibers (NFs) decorated by petal-like molybdenum disulfide (MoS 2 ) particles was designed through a facile hydrothermal method. The key parameters for tailoring the morphology and chemical, surface, and interfacial properties of the heterostructure were identified for efficient and selective conversion of CO 2 into valuable chemicals. Introducing MoS 2 layers onto NiTiO 3 NFs provided superior CO 2 conversion with significantly higher yields. The optimized hybrid structure produced CO and CH 4 yields of 130 and 55 μmol g -1 h -1 , respectively, which are 3.8- and 3.6-times higher than those from pristine NiTiO 3 nanofibers (34 and 15 μmol g -1 h -1 , respectively) and 3.6- and 5.5-times higher than those from pristine MoS 2 (37 and 10 μmol g -1 h -1 , respectively). This improved performance was attributed to efficient absorption of a wider spectrum of light and efficient transfer of electrons across the heterojunction. Effective charge separation and reduced charge carrier recombination were confirmed by photoluminescence and impedance measurements. The performance may also be partly due to enhanced hydrophobicity of the hierarchical surfaces due to MoS 2 growth. This strategy contributes to the rational design of perovskite-based photocatalysts for CO 2 reduction., Competing Interests: Author SK was employed by Pohang Iron and Steel Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Khan, Kang, Charles and Lee.)

Longevity has been a long-standing challenge for perovskite photovoltaics. In general, Li-TFSI/ t -BP are the state-of-the-art bi-dopants for the hole-transporting layer (HTL) in perovskite solar cells (PSCs), although such dopants significantly diminish the stability of devices. Here, we reported a novel dopant of fluorinated iron(III) porphine (Fe(III)-PP) as a potential alternative to the Li-TFSI/ t -BP. The optimized PSCs exhibit a champion power conversion efficiency (PCE) of 21.73%, which outperforms the standard bi-dopants Li-TFSI/ t -BP (21.07%). The high migration barrier together with the hydrophobic nature of the Fe(III)-PP, which in turn suppress intrinsic ion migration and alleviate extrinsic moisture-induced degradation, resulting in prominent improvement of long-term stability of PSCs up to 1200 h under air exposure without encapsulation. [Display omitted] • A novel dopant fluorinated iron(III) porphine (Fe(III)-PP) has been developed for PTAA in PSCs. • Fe(III)-PP has excellent doping performance, high migration barrier and hydrophobic nature. • PSCs based on Fe(III)-PP doped PTAA show a champion efficiency as high as 21.73%. • PSCs exhibit superior long-term stability up to 1200 h under air exposure without encapsulation. [ABSTRACT FROM AUTHOR]

• Maple leaf-derived biochars were prepared at the different pyrolytic temperature. • Biochar produced at 750 °C showed BET surface area of 191.1 m2/g. • Selected biochar presented maximum adsorption capacity of 361 mg/g. • Adsorption of tetracycline followed pseudo-second-order and Freundlich models. The present study evaluates the physicochemical properties of maple leaf-derived biochars (M-BCs) produced at different pyrolytic temperatures (i.e., 350, 550, and 750 °C) and their adsorptive properties for tetracycline onto M-BCs. The increase in pyrolysis temperature to produce M-BCs led to a significant increase in the biochar's hydrophobicity, surface area, and calcite (CaCO 3) crystallization. The M-BC750 produced without functionalization or activation possessed a high calcite composition and a hydrophobic nature with lower O/C and H/C, hydroxyl groups (–OH) on the surface, and functional groups (i.e., O-containing) as H-bond acceptors. Among M-BCs, the M-BC750 present a highest TC adsorption capacity owing to possible mechanisms such as metal complexation, H-bonding, and hydrophobic interactions. The isotherm and kinetic models for TC adsorption followed the Freundlich models and pseudo-second-order models, respectively. M-BCs produced from the waste fallen maple leaves could be applied as low-cost environmental adsorbents for TC removal. [ABSTRACT FROM AUTHOR]