Search

Magnesium cement product is an excellent fire-retardant material that has been extensively used in the building materials industry. But their strength and ability to withstand humid conditions still yet to be improved. The silicone-acrylate emulsion was utilized in this study to improve the water resistance and mechanical strength of the straw-magnesium cement (SMC) composites. The properties improvement mechanism and fire-retardant performances was also analyzed. For the SMC composites containing 6% silicone-acrylate emulsion, the modulus of rupture, internal bond strength and the strength retention coefficient after immersion have all increased significantly. In contrast, the thickness swelling, water absorption decreased dramatically. The analysis results showed that an organic-inorganic network structure was formed in the novel magnesium cement, which enhanced the integrity of the material and played a role in protecting the crystals against hydrolysis. With the enhanced water resistance and mechanical strength, the novel SMC composites broadened the use in humid environments and increased the service life. Their excellent fire-resistant properties make the novel SMC composites an ideal candidate for use in public venues.

Although hydrogel electrolytes have attracted considerable attentions due to high water retention and low leakage, their vulnerability and low conductivity still pose challenges in large-scale applications. In this work, a mechanically strong and highly conductive poly (acrylic acid) (PAA) electrolyte reinforced by cellulose nanofibrils (CNFs) is developed via versatile blending followed by polymerization. As a result of physical entanglement and hydrogen bonding, the mechanical strength of the PAA electrolyte is enhanced from 0.656 to 1.875 MPa at a CNF loading of 3 wt%, and the dimensional swelling is suppressed to half of its original level. The ionic conductivity of the composite electrolyte is improved by 100% due to excellent ion-transfer paths created by the hydroxyl groups exposed on the surfaces of CNFs. Furthermore, the CNF/PAAs exhibit preferable elasticity and flexibility with the maximum elongation at break reaching greater than 600%. These electrolytes are able to maintain the initial ionic conductivity even after being stretched to 100% elongation for 500 circles. After assembling with an air cathode and an aluminum anode, the as-prepared Al−air battery show good discharging performance, demonstrating promises for applications in portable and flexible electronic devices.

Lignin nanospheres/poly(vinyl alcohol) (LNS/PVA) nanocomposite films were prepared through solvent casting approach. Compared with lignin/PVA blend film, LNS could be evenly dispersed in PVA matrix, and the nanocomposite films did not generate macroscopic phase separation. Maximum decomposition temperature (Tmax) and glass transition temperature (Tg) of pure PVA film were 264.7 and 104.2 °C, while the Tmax and Tg of the nanocomposite film containing 1 wt % LNS increased to 272.1 and 116.8 °C, respectively. Moreover, with increasing of LNS content in PVA matrix, the Tmax and Tg of the nanocomposite films gradually increased. Adding a certain amount of LNS in PVA could improve mechanical strength of the films under the condition of elongation at break in a small amount of loss. The nanocomposite films outperformed the lignin/PVA blend film in UV-absorbing and transparency, which are a promising candidate for medicine bottles and food packaging.

To fully exploit the abundant bioresource crop straw, a straw-based composite with excellent fire retardant, high strength and dimensional stability was successfully prepared for use in building ap...

Fe3O4 is a negative electrode material with great development potential, but it remains a challenge for Fe3O4-based negative electrodes to attain excellent electrochemical performance and stability simultaneously with good flexibility, which limits their practical applications in high-performance flexible asymmetric supercapacitors (ASCs). In this study, a simple and scalable bottom-up strategy is presented to prepare three-dimensional (3D) porous CNF/MWCNT/GO-hybrid aerogels (HAs) based on one-dimensional (1D) cellulose nanofibers (CNFs) and multiwalled carbon nanotubes (MWCNTs) and two-dimensional (2D) graphene oxide (GO). After in situ embedding of Fe3O4 nanoparticles (∼200 nm) into the HA substrate, a high-performance flexible CNF/MWCNT/reduced-GO (RGO)/Fe3O4 electrode with a large capacitance of 1193 mF cm−2 and excellent rate capability as well as high durability has been synthesized. Moreover, when using this CNF/MWCNT/RGO/Fe3O4 as a negative electrode, the as-fabricated flexible ASC device exhibited a significant capacitance and energy density of 5.82 F cm−3 and 2.35 mW h cm−3, respectively. In addition, the flexible ASC device retained more than 94.7% of its initial capacitance after 5000 charge–discharge cycles. These results indicate that the proposed strategy can provide new opportunities for researchers to rationally design and prepare flexible ASC negative electrode materials with excellent capacitive properties, which will extend the application of such materials to the domain of portable and wearable electronics.

Although polymeric graphitic carbon nitride (CN) is considered an appealing metal-free photocatalyst for energy conversion and environmental remediation, its application still faces challenges owing to its limited photocatalytic activity under visible light irradiation. Herein, we prepared an efficient doped CN photocatalyst using sustainable cellulose nanofibrils (CNFs) to anchor Ag onto CN. The carbon originating from CNFs was doped successfully, which in consequence enhanced the visible light absorption of CN significantly. Furthermore, the carboxyls and hydroxyls exposed on the CNF surface, as well as the intrinsic entangled network of CNFs, provided more Ag chemically and physically anchored on the resultant CN framework. The Ag amount of Ag/CCN-4 (doped with CNF and 0.04 g of AgNO3) increased significantly, which was about 2 times higher than that of Ag/CN (doped with only AgNO3), and the band gap was narrowed to 2.30 eV. As a result, rhodamine B (RhB) and tetracycline (TC) were efficiently degraded under visible light, and the photodegradation rate constant of RhB reached 0.12695 min−1, whereas that of Ag/CN and CN was 0.06956 and 0.04892 min−1, respectively. The possible mechanism was summarized. Benefiting from the relatively higher specific surface area, carbon doping and Ag anchoring, Ag/CCN-4 exhibited excellent photocatalytic activity, and this work provides a simple and efficient strategy for fabricating high-performance CN photocatalysts for the removal of pollutants.

Structural colored nanocomposites with photonic liquid crystal structures are desirable owing to their excellent optical performances, unique structural features and intelligent responsive behaviors. Herein, a series of cellulose nanocrystal (CNC)-based nanocomposite materials that mimic the cholesteric structural colored creatures in nature were prepared and their functional applications investigated. Multicolored, flexible and intelligent responsive iridescent films were constructed by mixing cellulose nanocrystals (CNCs) and glycerol (Gly) in different ratios. Consequently, redshifted structural colors were obtained from the increase in the helical pitch of the chiral nematic structures according to the microstructure analysis. In addition to improving the mechanical properties of the composite films, glycerol also promoted the crystallinity of the films to different degrees. The CNC/Gly20 films exhibited reversible reflection colors at different relative humidity because of the strong water absorption capability of glycerol. Furthermore, CNC/Gly composite suspensions were used as photonic inks to obtain photonic writing with unique fingerprint textures. Moreover, the CNC/Gly nanocomposites were also used to make iridescent coatings on different substrates. The incorporation of glycerol improved the compatibility between the interfaces. Thus, photonic nanocomposites from cellulose nanocrystals can potentially be developed as optical sensors, security markings and functional coatings.

The efficient utilization of cellulose is very important for environmental protection and sustainability of resources. A cellulose derivative, cellulose nanofiber film, is a highly promising candidate for use in tissue engineering, electronics, and green packaging materials; however, water adsorption seriously impairs the properties of cellulose nanofiber film. In order to efficiently utilize this cellulose derivative, we need to qualitatively and quantitatively characterize its water adsorption. In situ micro-FTIR spectra of the cellulose nanofiber film were collected within a relative humidity (RH) range of 0–94%. The spectral information indicated effective adsorption sites for adsorbed water and identified three spectral regions closely associated with water absorption. Meanwhile, moisture contents of the cellulose nanofiber film were measured by dynamic vapor sorption as reference values. Using a partial least squares regression (PLS-R) method, the identified spectral regions closely associated with water absorption were used to construct a multivariate quantitative model to predict moisture contents of cellulose nanofiber film over the entire RH range. The predicted sorption isotherm confirmed the effectiveness of the micro-FTIR spectroscopy in quantitatively characterizing water adsorption of the cellulose nanofiber film at room temperature of 25 °C.

Disturbances among the receivers caused by irrelevant circuit topology and inductive cross couplings among the receiving coils are particularly problematic aspects of multi-receiver wireless power transfer (WPT) systems. This paper proposes an effective and convenient scheme in which a K-inverter is inserted between an approximately $0~\Omega $ output impedance voltage source and a transmitting resonator in order to isolate the receivers from each other, where the voltage and power distributed to each load are independent of other loads. The load-isolation principle is illustrated in detail. The indirect cross coupling aggravating the cross interferences is also investigated, and some practical criterions are derived to eliminate them. A three-receiver WPT experimental platform was established and tested to verify the theory; measured results were in close agreement with the theoretical values.

A wood-derived nanocellulose hydrogel (WNH) with gold nanoclusters (Au NCs) was prepared by in situ multistep reactions, which was used as an effective adsorbent for the adsorption of mercury ion (Hg2+) and a solid-state fluorescent probe for detecting Hg2+. The WNH’s morphology, chemical structure and optical properties were investigated. The adsorption performance of WNH towards the Hg2+ ion was studied, indicating that the sorption data were well fitted by Langmuir and pseudo-second-order models with a maximum sorption capacity of 234.4 mg/g. The detection performance of WNH towards the Hg2+ ion was also investigated, showing excellent selectivity and sensitivity to Hg2+ with a detection limit of 0.09 μg/L. The 3D porous structure created by wood-derived nanocellulose increased adsorption and detection, according to the mechanism analysis. Furthermore, a cost analysis was performed for WNH and commercial activated carbon, and the results showed that WNH was the economically viable option for Hg2+ sorption. This research could pave the way for a low-cost, multi-functional and environmentally friendly mercury adsorbent.

Although there is a growing interest in utilizing nanocellulose fibres (NCFs) based composites for achieving a higher sustainability, mechanical performance of these composites is limited due to the poor compatibility between fibre reinforcement and polymer matrices. Here we developed a bio-nanocomposite with an enhanced fibre/resin interface using a hybrid-toughened epoxy. A strong reinforcing effect of NCFs was achieved, demonstrating an increase up to 88% in tensile strength and 298% in tensile modulus as compared to neat petro-based P-epoxy. The toughness of neat P-epoxy was improved by 84% with the addition of 10wt% bio-based E-epoxy monomers, which also mitigated the amount of usage of bisphenol A (BPA). The morphological analyses showed that the hybrid epoxy improved the resin penetration and fibre distribution significantly in the resulting composites. Thus, our findings demonstrated the promise of developing sustainable and high performance epoxy composites combing NCFs with a hybrid petro-based and bio-based epoxy resin system.

Bonding strength in the structure of engineered wood products and composites is one of the vital properties for their application. Up to now, numerous research efforts have been made on improving durability, wettability, and strength of resins or adhesives. However, there are only a few reports on how to improve bond line strength according to wood feature itself. In this study, a new conceptual bonding design based on wood radial section feature was reported. In this design, finger-joint like bonding interfaces were generated by hot pressing two resin coated wood radial sections together at optimized pressure of 300 lb per square inch (psi). By this design, the wet bonding strength of the bond line has potential to be higher than dry bonding strength. Meanwhile, with a compression ratio of 7.3% of wood strips, the obtained dry bonding or shear strength has been significantly increased up to 33.9%, as compared to end matched tangential controls. Wood specific gravity played an important role in this design. A proper compression ratio explored here in the radial section was about 17%. This work has provided a new route to improve wood bonding strength in an environmentally friendly way. Its impact on bending strength and dimensional stability of bonded wood structures needs to be further investigated.

Lignin is the most abundant renewable aromatic polymer in the world, but its complex structure makes it difficult for efficient utilization. In this study, lignin-based porous carbon (LPC) was prepared through hydrothermal treatment and KOH activation and then used as an adsorbent for the adsorption of methylene blue (MB). The influence of contact time, initial MB concentration, solution pH and adsorption selectivity on adsorption performance was explored. Hierarchical LPC showed a high specific surface area up to 3382.32 m2/g and a large number of active sites. The maximum adsorption capacity of MB was as high as 1119.18 mg/g. The adsorption kinetic was in well agreement with pseudo-second-order model. Langmuir isotherm model fitted well to the adsorption experimental data. The maximum adsorption capacity calculated from Langmuir isotherm model (1119.65 mg/g) approached the experimental result. Moreover, the LPC exhibited the outstanding selective adsorption property to cationic dyes, where the adsorption capacities of malachite green and rhodamine B were 2467.30 mg/g and 1657.82 mg/g, respectively. In addition to electrostatic interaction due to the negatively charged surface of LPC, hydrogen bonding and π - π stacking interactions were responsibility for the adsorption mechanism. On account of low-cost, excellent adsorption properties and favorable reusability, the LPC has the promising potential as a lignin-based absorbent for removing cationic dyes in wastewater treatment.

Wood fibers are used as raw materials for construction and furniture owing to their specific mechanical performance, cost, and availability. However, the unsatisfactory flame retardancy and antibacterial properties of wood fibers have limited their application. In this study, the flame-retardant and antibacterial wood fibers were synthesized via metal phenolic networks (MPNs). Successive immersion of tannic acid (TA) and ferrous salt was conducted to modify wood fiber with the fabrication of a TA-Fe-wood complex, which was then superficially coated with a layer of silver nanoparticles (AgNPs) to fabricate TA/Fe/AgNPs@wood fibers via a redox reaction. Compared with untreated wood fibers, the TA/Fe/AgNPs@wood fibers demonstrate a 71.5 % reduction in peak heat release rate and a 56.5 % reduction in peak smoke production rate as well as increased char formation, indicating a significant improvement in fire resistance. The modified fibers also exhibit excellent antibacterial activity against two common pathogenic bacteria, E. coli and S. aureus. The exterior color of the modified wood fibers was modified by double pulse TA impregnation, solving the problem that MPNs darken the substrate. These fibers can be widely used in the fields of adsorption, construction, paving and greening.

Structural design is the fundamental approach to improve the catalytic properties for oxygen evolution reaction (OER). Herein, an ingenious three-dimensional hierarchical porous heterostructure that well-aligned NiFe layered double hydroxide nanosheets deposited on NiFe nanoparticles and rooted tightly into carbonized wood framework (NiFe-LDHs@NiFe/CW) is developed, and the resultant electrocatalysts perfectly retains the characteristic structure of wood and forms a heterostructure. Benefitting from the abundant hetero-interfaces, optimized electronic configuration, and hierarchical pores, the NiFe-LDHs@NiFe/CW has remarkable electrocatalytic activity and stability toward OER, which possesses a low overpotential of 212 mV at 50 mA cm−2 and insignificant potential increase (≈4.0%) at 50 mA cm−2 for 100 h. Density functional theory (DFT) calculations further reveal that the heterostructures can optimize the electronic structure and have the lowest adsorption energy, thus accelerating the catalytic kinetics. The strategy reported may benefit particularly to utilizing natural and renewable resources to design high-performance electrocatalysts.

Although lignocellulosic biomass has promising applications in biodegradable cellulose-based composite materials due to its high specific surface area and high rigid intensity, lignocellulosic fiber with multiple surface reactive sites and intact spatial structure is still a great challenge as a versatile carrier for composite materials. Herein, a feasible strategy that combined alkaline hydrogen peroxide (AHP) impregnation and two-step mechanical refining was presented to treat the pondcypress (taxodium ascendens) for enhancing cellulose accessibility and specific surface area. Additionally, the prepared pondcypress fiber kept the intact spatial structure. First, the destruction of molecular structure barrier was synergistically realized by the NaOH and H2O2, that improved the efficiency of 2nd mechanical refining. Subsequently, the fibers exhibited an excellent dissociated result under the effect of shear stress and friction at low energy consumption (1637 kW h/t). As a result, the fibers achieved ultrahigh cellulose accessibility of 77.07 % and high surface active hydroxyl content of 2.164 × 10−3 mol/g due to the exposure of S2 cell wall at the 16 % H2O2 and 17.5 % NaOH. Moreover, despite the fibers were fibrillated after treatments, the intact spatial structure of fiber was observed by SEM. These results confirm that AHP impregnation and two-step mechanical refining are an effective method to dissociate the fiber, and this work opens up more avenues to use the lignocellulosic fiber in cellulose-based composite materials.

Heavy metal pollution is one of the primary challenges of water pollution, and the fabrication of highly effective, green and non-toxic adsorbents for heavy metals is urgently required on the basis of environmental and sustainable development strategies. Here, we report a novel fluorescent wood (FW) with effective adsorption ability (maximum theoretical adsorption capacity of 98.14 mg/g for hexavalent chromium [Cr(VI)]), good fluorescence properties (absolute quantum yield of 12.8%), non-cytotoxicity (cell viability of >90%) and high detection sensitivity and selectivity for Cr(VI). The FW was formed using a process involving delignification, infiltration with carbon dots, and free-radical polymerization with acrylic acid. Mechanistic analysis confirmed that the reconstructed 3D porous structure of the FW provided many effective sorption sites, such as amino, hydroxyl and carboxyl groups. This improved the adsorption ability and stabilized the fluorescence signal, which enhanced the detection ability. These factors give the novel FW considerable potential for use in the removal of Cr(VI) ions from wastewater.

Island-like structure induced by hydroxyl groups has been demonstrated to pose significant influence on tuning surface morphology and wettability. Herein, with an intention to better understand this structural transformation, hydroxyl groups both from nanoparticles and substrates were controlled during the thermally-driven deposition procedure. The results show that hydroxyl groups originated from nanoparticles facilitate the fabrication of island-like structure, while these groups from substrates confine. Representatively, hydroxyl-rich TiO2 nanoparticles prefer to generate island-structure and lead to a higher water contact angle, yet hydroxyl-poor copper substrates enable the fabrication of such structure. Morphology observation convinces that nanoparticles abounded with hydroxyl groups were preliminarily grown into larger-size clusters in starting emulsion due to strong intermolecular forces, which contributes to the structural transformation from incompact layer-like to island-like. Meanwhile, the hydroxyl groups in substrates promote the uniform distribution of nanoparticles due to strong hydrogen bonding, which results in a dense and continuous layer-like surface structure. As the island-like structure improves the superhydrophobicity and bonding strength between interfaces, the surfaces with this morphology present high performances. Differing from previous findings, this work will open a new insight into the transformation of island-like structure driven by hydroxyl groups, and afford an alternative strategy to optimize the design of high-performance superhydrophobic surfaces.

β particles were used to dissociate the Bi − O bond in layered microsphere-like Bi2WO6 to obtain Bix@Bi2-xWOn with oxygen defects. Bi0.32@Bi1.68WO5.80 with Bi0 treated at 4.50 × 1015 MeV can realize the completely removal of oxytetracycline (OTC) within 20 min. Free radical scavenging experiments showed that the removal rate of OTC for Bi0.32@Bi1.68WO5.80 dropped to 11.39% after removing ∙OH radicals. Additionally, the LC-MS results revealed that the ∙OH radicals first oxidized the unsaturated C = C double bond and opened the hexatomic ring, making OTC easier to degrade. The DFT results confirm that the electron cloud density at the oxygen defect site has expand, thereby promoting the photocatalytic reaction. Bi0.32@Bi1.68WO5.80 with lowest O negative polarization rate verified that lattice oxygen defects produced by β particles enhance the generation of ·OH free radicals that activate SO42− to produce ∙SO4− radicals. It is be confirmed that ∙OH radicals can activate SO42− to form ∙SO4−.This work provides a new strategy for forming oxygen defects in photocatalytic. This work provided a new strategy for the efficient utilization of ∙OH radicals by β-rays in the field of catalytic oxidation.

There are significant challenges related to practical applications of superhydrophobic materials due to their limited durability, difficult processing conditions, and complicated synthesis procedures. In this study, a facile and novel emulsion composed of nanopartilcles (i.e. SiO 2 or TiO 2 ) and epoxy resin was synthesized to produce superhydrophobic surfaces using spraying, dipping and brushing methods, mimicking ordinary household paints. The obtained superhydrophobic materials had a water contact angle (CA) of ∼152° and a sliding angle (SA) of ∼6° at the room temperature. Interestingly, the emulsion demonstrated a great versatility for application in type of materials and application methods. The hierarchical surface structure fabricated by the emulsion was found to be independent of the substrate type and processing method, resulting in similar water repellent performance among all surfaces obtained. The superhydrophobic surfaces also exhibited excellent durability even after sustaining a series of mechanical damages including finger wiping, tape peeling and sandpaper abrasion. Moreover, they were able to maintain their superhydrophobic performance after immersion in aqueous solutions of pH ranging from 1 to 13 and boiling in water at 100 °C. This study shows that the novel emulsion can be used to fabrication of superhydrophobic surfaces using a one-step method that is green, versatile, scalable and independent of operator skill, special equipment, and the type of substrate. It has an excellent promise for real life applications.

Reusable and porous aerogel was fabricated using natural cellulose nanofibrils (CNFs) cross-linked with acrylic acid (AA) for the removal of heavy metal ions. CNFs with diameters of 5–50 nm were obtained and the cross-linking mechanism of CNFs with AA (CA aerogel) was analyzed. The CNFs based aerogel formed highly porous networks after cross-linking with AA and carboxyl groups were introduced onto the molecular chain of CNFs. The maximum adsorption capacities of CA aerogel for Cu(II) and Pb(II) were 40.01 and 130.36 mg/g and the adsorption closely followed the pseudo-second-order kinetic and Langmuir isothermal model for both Cu(II) and Pb(II). Chemical adsorption combined with porous physical adsorption endowed CA aerogel excellent adsorption properties. The prepared CA aerogel showed desirable reusability and could remove various heavy metal ions in industrial sewage. This resulted CA aerogel was considered to be promising alternative for conventional adsorbents in fields of sewage recovery, water purification, and soil remediation. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

First, ethyl cellulose-g-poly(2-(dimethylamino) ethyl methacrylate) (EC-g-PDMAEMA) was synthesized through atom transfer radical polymerization. Second, the polymer was used to prepare self-support...

Engineering porous heteroatom-doped carbon nanomaterials with remarkable capacitive performance is highly attractive. Herein, a simple and smart method has been developed to synthesize phosphorus (P) doped carbon with hierarchical porous structure derived from lignocellulose. Hierarchically porous P doped carbon is readily obtained by the pyrolysis of lignocellulose immersed in ZnCl2/NaH2PO4 aqueous solution, and exhibits excellent capacitive properties. The as-obtained P doped porous carbon delivers a significant capacitance of 133 F g−1 (146 mF cm−2) at a high current density of 10 A g−1 with outstanding rate performance. Furthermore, the P doped carbon electrode yields a long-term cycling durability with more than 97.9% capacitance retention after 10000 cycles as well. A symmetric supercapacitor with a maximum energy density of 4.7 Wh kg−1 is also demonstrated based on these P doped carbon electrodes.

In situ micro-Fourier transform infrared (FTIR) spectra of a typical cellulose nanofiber (CNF) film (i.e., CNF with cellulose I structure) were collected within the full relative humidity (RH) range from 0% to 90%. Red shifts of two peaks at 1036 and 1204 cm−1 and the variation of different spectra indicated the chemical adsorption sites for adsorbed water. From component band analysis of the spectral range of 2900–3700 cm−1, three component peaks at 3293, 3397, and 3543 cm−1 were due to strongly, moderately, and weakly hydrogen-bonded water. The signatures of these three types of hydrogen-bonded water were then observed to rise with an increase in RH. Based on growth regularities of these three types of hydrogen-bonded water, the water adsorption process of CNF film was divided into three stages; most of the water absorbed in these three stages was demonstrated to be CNF⋅⋅⋅HOH⋅⋅⋅CNF, WATER⋅⋅⋅⋅HOH⋅⋅⋅⋅WATER, and five-molecule tetrahedral structure, respectively.

In this article, the low-field nuclear magnetic resonance was used to measure the moisture content (MC) and MC profiles in poplar wood during real-time drying. The T2 distribution curve at each drying stage measured using the Carr–Purcell–Meiboom–Gill pulse sequence provided detailed information in the dynamic change of free water as well as bound water of the whole wood sample. In addition, a new developed SE-SPI pulse sequence was first used to evaluate the spatially resolved T2 distribution of the successive nondestructive sliced layer of wood. Combined with the area integration method, the moisture content in each layer was calculated, and the change of MC profiles within wood at the MC above and below fiber saturation point was well reflected.

The adsorbed water influences significantly, the physical and mechanical properties of wood. In the present paper, the spatial distribution of adsorbed water in wood cell walls has been studied by μ-Fourier transform infrared (μ-FTIR) and confocal Raman spectroscopy. In situ μ-FTIR spectra were collected from three randomly selected areas in different cell wall regions, which were exposed to an environment with 0% to 96% relative humidity (RH). The water adsorption sites were easily detectable based on OH, C=O, and C-O group vibrations and it was shown that the adsorbed water concentration was not uniform in different regions. Confocal Raman spectroscopy images were collected from the cell corner (CC) and middle layer of the secondary wall (S2) and the non-uniformity of water distribution could also be confirmed by this approach. It was demonstrated that both μ-FTIR and confocal Raman spectroscopy provide valuable information about the spatial distribution of adsorbed water in morphologically distinct cell wall regions.

The main objective of this work was to study a new inorganic adhesive used for wood-based panel. Inorganic adhesive and its poplar plywood were prepared to investigate their properties. Thermo-gravimetric analysis tests revealed that the total mass loss of inorganic adhesive was 76.24%, which was higher than that of phenol-formaldehyde resin (64.97%). The results showed better thermal stability of inorganic adhesive. For inorganic adhesive plywood, approximately 30% decrease in peak of heat release rate, 62% in total smoke production and 20% in mean CO2 yield, respectively, were seen compared to the control by cone calorimeter analysis. Scanning electron microscopy imaged wider glue line of inorganic adhesives plywood, which was related to the bonding strength of plywood. Thus the inorganic adhesive of fireproofing made in lab could be better used for plywood processing.

The application of superhydrophobic wood is majorly limited by its durability when subjected to natural conditions. Herein, the stability of two representative superhydrophobic woods (i.e., Poplar (Populus tomentosa) and Chinese fir (Cunninghamia lanceolata)), were prepared via a one-step hydrothermal process using tetrabutyltitanate (Ti(OC4H9)4, TBOT) and vinyltriethoxysilane (CH2CHSi(OC2H5)3, VTES) as a co-precursor and sequentially tested under different humidity and temperature conditions. The variables including morphology, water contact angle (WCA), color parameter, chemical components of the surface, and moisture absorption property were characterized using a scanning electron microscope (SEM), WCA measurement, a colorimeter, a Fourier transform infrared (FTIR) spectroscopy, and a moisture absorption test, respectively. It was found that initial static WCAs of superhydrophobic wood were larger than 150°. Micron-sized cracks were formed on the coatings after the alternating humidity and temperature aging cycles. This lowered the water repellency, but the WCA was still greater than 140°. There was nearly no chemical change of wood after the aging test; the color change between the same species of untreated and superhydrophobic wood was very small, only with a difference of 0.42 and 4.05 in overall color change ΔE∗ values for Chinese fir and poplar, respectively. The superhydrophobic coatings had a trivial influence on wood moisture absorption property, which only lowered 3% in poplar and 2% in Chinese fir, respectively. Keywords: Superhydrophobic wood, Accelerated aging, Water resistance, Moisture absorption

Cellulose nanofibers (CNFs) were prepared through acid hydrolysis and used in combination with graphene nano-platelets (GNPs) as modifiers for oil well cement (OWC). The rheology behavior of CNF/GNP-OWC slurries at three temperatures (i.e., 20, 40, and 60 °C) was measured and modeled using four different rheological models. Thermal properties, surface functional groups, morphology, and mechanical performance of the composites were characterized. CNF/GNP-OWC slurry exhibited a typical shear-thinning behavior with reduced shear viscosity at higher shear rates. The use of CNFs and GNPs led to increased yield stresses of fresh CNF/GNP-OWC slurry and temperature significantly influenced the yield stress values. Among these rheology models, the Vom Berg model exhibits the best fitting result of the slurry rheology data (R2 = 0.999). The addition of CNFs and GNPs increased degree of hydration (DOH) value of CNF/GNP-OWC composites. Both flexural and compressive strengths of the CNF/GNP-OWC composites were enhanced with added CNFs and GNPs. The reinforcing mechanism was attributed to the increased DOH, reduced pores, and bridging effect of CNFs and GNPs in the composites. Keywords: Nanocellulose, Graphene nanoparticle, Oil-well cement, Rheology, Curing, Strength

Creation of sustainable, cost-effective, and scalable absorbents with ideal absorption properties is a worldwide challenge because many high-performance absorbents are still restricted in laboratory scope due to several critical defects (like complex and eco-unfriendly synthesis process, high cost, and difficulty in large-scale production). Herein, a facile and scalable top-to-bottom design is proposed to create a kind of novel anisotropic carbon aerogels with low tortuosity of stacked laminated structure, derived from the hierarchical cellular channels of balsa wood. By virtue of this unique structure and favorable oleophilicity, fast passive capillary absorption with low flow resistance is achieved (as demonstrated by the theoretical modeling). As a result, the anisotropic carbon aerogels have quite sensitive selectivity to separate organic pollutants from water, broad-spectrum and high absorption capacity for different organic liquids (13 277–31 597 mg g–1), and superior recyclability (98.7% absorption...

To improve the hydrophobicity and thermoplastic processability of starch, lactic acid esterified starch (LA-e-starch) was prepared by in-situ solid phase esterification with corn starch as the raw material and LA as the esterifying agent. Fourier transform infrared spectroscopy confirmed that the esterification reaction was successful. The optimal esterification efficiency of LA-e-starch was obtained when the LA proportion was 20% by mass, catalyst ratio at 3%, reaction temperature 80 °C and reaction time 2.5 h. LA-e-starch was characterized by scanning electron microscopy (SEM), contact angle (CA) analysis, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) as well as its water absorption rate evaluated. Results showed that in-situ solid phase esterification mainly occurred on starch granule surfaces and did not destroy the starch granularity. LA-e-starch surfaces were covered with a layer of polylactic acid resin, which caused starch granules to stick together. The initial contact angle of LA-e-starch was clearly larger than that of native starch and the water absorption rate lower than native starch in a 168 h test time, which showed that esterification effectively improved the hydrophobicity of starch. This esterification destroyed the crystalline structure of starch to some extent, resulting in a crystallinity reduction to 25.16%. In addition, the gelatinization temperature and enthalpy were lower than those of native starch. XRD and DSC analyses indicated that esterification modification increased starch thermoplasticity. Also, LA-e-starch exhibited better thermal stability than native starch, from which it was inferred that this application of esterification could improve the thermoplastic processability of starch modify the interfacial compatibility between starch and polymer resins.

To compare The effects of organic and inorganic impregnation on the properties of unmodified, phenol formaldehyde oligomer-modified (PFOMCF), and sodium silicate-modified Chinese fir wood (SSMCF) were compared using samples prepared using the respiratory impregnation method. Impregnation and reinforcement effects and water resistance of PFOMCF and SSMCF were compared and the results was showed that the weight percentage gain, density increase rate, bending strength, and compressive strength of SSMCF were clearly higher than those of PFOMCF and had a lower water absorption rate within 60 h. The impregnation and reinforcement effects and dimensional stability of SSMCF were better than those of PFOMCF. FT-IR, XRD, CONE, and TGA examinations were used to test and analyze the chemical structure, crystalline structure, flame retardancy, and heat resistance of these modified woods. The results indicated that SSMCF possessed more hydrogen bonds than PFOMCF and that Si–O–Si chemical bonding with high bond energy was formed. Meanwhile, the weakened degree of the diffraction peak of SSMCF was much less than that of PFOMCF. These results explained that the mechanical properties and water resistance of SSMCF were better than PFOMCF. Compared with PFOMCF, SSMCF had a lower heat release rate (HRR), peak-HRR, mean-HRR, total heat release, smoke production rate, and total smoke production as well as higher thermal decomposition temperature and residual rate. Inorganic sodium silicate was shown to be a better flame retardant, while SSMCF had good smoke suppression effects, thermal stability, and safety performance in the case of fire.

Rice grading has achieved raising attention in recent years for its importance in food security, whereas progress is limited. The difficulty in this topic says that the rice kernels are crowed in the visual field of, say a camera, which makes the detection of a single kernel hard. In this paper, we are based on a newly designed rice streaming system and propose a novel rice grading model. The streaming system snapshots a kernel from three different visual directions, producing three images of a single kernel. The FIST-Model analyses these images by employing a multi-view learning method which minimizes the information loss and generates an intact representation of the rice kernel. Such a representation remains strong discriminability and is effective to determine the grading level of the rice. Finally, we evaluate the performance of the proposed FIST-Model on the FIST-Rice dataset by setting a series of experiments based on different deep learning models. The result indicates that the FIST-Model has a superior performance over previous rice grading model.

Exploring high-efficiency, stable, and cost-effective bifunctional electrocatalysts for overall water splitting is greatly desirable and challenging. Herein, a newly designed hybrid catalyst with Cr-doped FeNi-P nanoparticles encapsulated into N-doped carbon nanotubes (Cr-doped FeNi-P/NCN) with unprecedented electrocatalytic activity is developed by a simple one-step heating treatment. The as-synthesized Cr-doped FeNi-P/NCN with moderate Cr doping exhibits admirable oxygen evolution reaction and hydrogen evolution reaction activities with overpotentials of 240 and 190 mV to reach a current density of 10 mA cm-2 in 1 m KOH solution. When used in overall water splitting as a bifunctional catalyst, it needs only 1.50 V to give a current density of 10 mA cm-2 , which is superior to its typically integrated Pt/C and RuO2 counterparts (1.54 V @ 10 mA cm-2 ). Density functional theory calculation confirms that Cr doping into a FeNi-host can effectively alter the relative Gibbs adsorption energy and reduces the theoretical overpotential. Additionally, the synergetic effects between Cr-doped FeNi-P nanoparticles and NCNs are regarded as significant contributors to accelerate charge transfer and promote electrocatalytic activity in hybrid catalysts.

Three kinds of hydrophobic groups grafted starches of maleic anhydride grafted starch (MAH-g-starch), lactic acid grafted starch (LA-g-starch), and methyl acrylate grafted starch (MA-g-starch) were prepared by in situ solid phase polymerization. The results of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed successful grafting. The grafting ratios of MAH-g-starch, LA-g-starch, and MA-g-starch were 6.50%, 12.45%, and 0.57%, respectively. Influenced by the grafting ratio, LA-g-starch had the best relative hydrophobicity and the largest molecular weight, and those for MA-g-starch were the worst. The surfaces of grafted starches were covered with graft polymer, with obvious surface roughness and bond degree of MAH-g-starch and LA-g-starch. The crystalline structure of grafted starches showed some damage, with LA-g-starch exhibiting the greatest decrease in crystallinity, and less of a change for MA-g-starch. Overall, the grafting reaction improved thermoplasticity, with LA-g-starch the most improved, followed by MAH-g-starch, and then MA-g-starch.

Moisture sorption has a great impact on the mechanical properties of lignin. To better characterize the moisture sorption of lignin, an approach for in situ qualitative and quantitative analysis of moisture adsorption in nanogram-scaled lignin by using micro-FTIR spectroscopy and partial least squares regression is introduced in this study. Spectra of nanogram-scaled lignin were collected within the relative humidity (RH) of 0%–92%. A qualitative analysis of these measured spectra confirmed the effective water sorption sites and determined spectral ranges related to moisture adsorption. Using these identified spectral ranges, a quantitative forecasting model for the moisture content (MC) of lignin was built and developed according to partial least square regression (R2, 0.9996; RMSECV, 0.408; RMSEP, 0.118). Furthermore, the water sorption isotherm of lignin was acquired using the established forecasting model in which a very positive correlation between the estimated and measured MCs was demonstrated using a dynamic vapor sorption (DVS) setup. The results confirmed the practicability and effectiveness of this in situ qualitative and quantitative analysis approach.

To expand the application of magnesium oxychloride cement (MOC) as a kind of engineering materials in the construction field, organic–inorganic hybrid modifications were performed. Waterborne epoxy resin/magnesium oxychloride composites (WER/MOC) with high-strength and water-resistance were prepared using a simple and green method with MOC as matrix and WER as reinforcement. The effects of WER on the resulting composite’s viscosity, mechanical strength, water resistance, phase composition, thermal stability, and micromorphology were discussed. The results demonstrated that WER reduced the viscosity of the WER/MOC complex system, and the composite water resistance and compressive strength were improved, which were mainly attributed to chemical reactions between WER and MOC to form a crosslinked network structure. Meanwhile, XRD analysis results showed that the intensity of the diffraction peak of the 3-phase decreased and 5-phase increased with WER addition to the composite and no new crystal phase appeared. The compressive strength, water resistance, thermal stability, and porosity of these WER/MOC composites reached the best values when the WER mass proportion was 4.8%. Here, the composite water absorption rate decreased to 8.7%, softening coefficient increased to 17.8%, middle compressive strength (sealed for 7 d) at 48.0 MPa, and dry bulk density increased to 1.34 g/cm3. Thus, these WER/MOC composites were suitable for use as engineering materials in the construction and road industries.

A new type of nanocellulose/poly(vinyl alcohol)/carbon dot (NPC) multifunctional hydrogel was successfully fabricated by an one-step in-situ hydrothermal method. The one-pot strategy led to the formation of a complex hydrogen bonding/dynamic boric acid ester/nitrogen-doped carbon dots network, and endowed the hydrogel with multifunctionality. The hydrogel underwent self-healing at room temperature (25 °C) and exhibited double-emission fluorescence and high mechanical strength (tensile strength of up to 2.98 MPa). An NPC hydrogel-based capacitive sensor exhibited remarkable linear capacitance responsiveness toward pressure, strain, and glucose concentration, and enabled real-time synchronous quantitative pressure/glucose sensing with multiple linear correlations, which was a key performance criteria for biomechanical sensors. The versatility and multiple advantages of the as-prepared hydrogel demonstrate the potential of biological-mechanical sensing materials using natural cellulosic biomass.

To solve the problem of agricultural waste, modified straw/magnesium oxychloride lightweight composites (M−SMOCL) with light-weight and high strength were prepared using magnesium oxychloride cementitious material (MOC) as the matrix, modified straw as reinforcing material and other reagents as additives. The effects of coupling agents, including KH-550, KH-560, KBM-603, HY-201, on straw groups and water absorption, as well as the mechanical strength and water resistance of the composites, were examined and discussed. The results showed that coupling agents reduced straw hydrophilicity and water absorption, improved composite performance. KBM-603 in particular possessed the best modification effects, with water absorption of straw treated with KBM-603 decreased to 27%, and the composite compressive and bending strengths of reached the maximum values of 12.93 MPa and 4.78 MPa, respectively. FT-IR and SEM showed that straw treated with KBM-603 bonded more closely to the matrix, creating the best interface results.

Engineering nanostructured electrodes with elaborately interfacial compatibility is highly desirable for high-performance electrochemical devices. Herein, inspired by the porous structure of wood, a robust hierarchical architecture is constructed by coupling nickel materials with partially delignified (treated) wood through chemical bonding. After calcination and oxidation, a free-standing electrode (Ni–NiO/CTW) with an inherited hierarchical structure that integrates the nanostructured Ni–NiO with carbonized treated-wood (CTW) is developed. The obtained electrode exhibits a high capacity (7.40 F/cm2 at 10 mA/cm2) and good conductivity (7 Ω). Upon coupling the Ni–NiO/CTW cathode with a CTW anode, the as-prepared Ni–NiO/CTW//CTW supercapacitor delivers a high energy density of 1.44 mWh/cm3 (52.94 mW/cm3) and good cycling stability (97.8% capacity retention after 4000 cycles). Furthermore, a Ni–Zn battery is assembled by utilizing Ni–NiO/CTW as the cathode and a zinc plate as the anode. The fabricated Ni–NiO/CTW//Zn battery also displays excellent performance with a high areal capacity of 1.4 mA h/cm2 at 10 mA/cm2. In addition, the maximum energy density of the battery is 16.97 mWh/cm3 (121.60 mW/cm3) and the peak power density is 353.57 mW/cm3 (13.65 mWh/cm3). Due to these advantageous features, the free-standing Ni–NiO/CTW electrode is promising for widespread application in high-performance energy storage systems.

Traditional waterproofing strategies (e.g. plastic seals, superhydrophobic coatings) of strain sensors greatly limit their sensing performance (e.g., sensitivity, working-range, and working-life). Here a unique ultra-stretchable, coating-free superhydrophobic material is developed for high-performence strain sensing in harsh environments. This material integrates high sensitivity (GF of 2.1 to 214), wide sensing range (up to 447% strain), low resolution (

To deal with heavy metal pollution, a novel fluorescent chitosan-based hydrogel incorporating titanate and cellulose nanofibers modified with carbon dots was prepared to effectively detect and remove Cr(VI). The composition and structure of this chitosan-based hydrogel were analyzed. The performance of the fluorescent chitosan-based hydrogel in Cr(VI) adsorption was evaluated through a contrast experiment with the normal chitosan hydrogel without carbon dots. The results showed that the fluorescent chitosan-based hydrogel had a higher adsorption ability of Cr(VI) (maximum adsorption capacity, 228.2 mg g−1). The effect of the initial concentration of Cr(VI) and the contact time were also evaluated. The results confirmed that the adsorption isotherm was according to the Langmuir model, and the adsorption kinetics followed the pseudo-second-order model. Furthermore, as a fluorescent sensor for Cr(VI), the detection sensitivity and selectivity were examined. The quantitative detection of Cr(VI) was achieved in the linear range of 10–80 mg L−1. Furthermore, for this fluorescent chitosan-based hydrogel, the mechanism for highly efficient adsorption and detection of Cr(VI) was analyzed via FTIR and XPS. These results showed that the excellent sorption and sensing abilities of Cr(VI) may be mainly attributed to the porous structures and the additional titanate and cellulose nanofibers modified with carbon dots improving sorption ability of Cr(VI) and providing a rapid visual response to Cr(VI).

To effectively detect and remove environmentally hazardous Cr(VI), a novel 3D porous fluorescent hydrogel was synthesised using amino-modified carbon dots and cellulose nanofibers. The synthesised fluorescent hydrogel was characterized to determine its morphology, crystalline structure, chemical composition and optical property using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV-vis absorption spectroscopy and photoluminescence spectroscopy. The sorption properties of the synthesised fluorescent hydrogel were further analyzed. The maximum sorption capacity for Cr(VI) reached 534.4 mg/g, the adsorption isotherm was well fitted using Langmuir model, and the adsorption kinetics were well fitted using a pseudo-second-order model. The sensing ability of the synthesized hydrogel for Cr(VI) was also determined. Furthermore, the mechanism of Cr(VI) sorption and sensing was determined. Accordingly, this novel 3D porous fluorescent hydrogel was identified to be a promising sorbent with advantages of excellent sorption and sensing abilities for environmentally hazardous Cr(VI).

In this study, an efficient, facile method has been developed for fabricating superhydrophobic surfaces on wood substrates using silica nanoparticles modified by VTES. The as-prepared superhydrophobic wood surface had a water contact angle of 154° and water slide angle close to 0°. Simultaneously, this superhydrophobic wood showed highly durable and robust wear resistance when having undergone a long period of sandpaper abrasion or being scratched by a knife. Even under extreme conditions of boiling water, the superhydrophobicity of the as-prepared wood composite was preserved. Characterizations by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy showed that a typical and tough hierarchical micro/nanostructure was created on the wood substrate and vinyltriethoxysilane contributed to preventing the agglomeration of silica nanoparticles and serving as low-surface-free-energy substances. This superhydrophobic wood was easy to fabricate, mechanically resistant and exhibited long-term stability. Therefore, it is considered to be of significant importance in the industrial production of functional wood, especially for outdoor applications.