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Cu2+ contamination and food spoilage raise food and drinking water safety issues, posing a serious threat to human health. Besides, Cu2+ and H 2 S levels indicate excess Cu2+-caused diseases and protein-containing food spoilage. Herein, a coumarin-containing bifunctional paper-based fluorescent platform integrated with a straightforward smartphone color recognition app is developed by an all-in-one strategy. The proposed fluorescent materials can simultaneously detect Cu2+ and H 2 S for on-demand food and drinking water safety monitoring at home. Specifically, a coumarin-derived fluorescence sensor (referred to as CMIA) with a low detection limit (0.430 μM) and high-selectivity/-sensitivity for Cu2+ is synthesized through a simple one-step route and then loaded onto commercially used cellulose fiber filter paper to engineer a biomass-based fluorescent material (CMIA-FP). The CMIA-FP offers user-friendly, high-precision, fast-responsive, and real-time visual monitoring of Cu2+. Moreover, CMIA forms a chemically stable complex with Cu2+, loaded onto filter paper to prepare another biomass-based fluorescent platform (CMIA-CU-FP) for visual real-time monitoring of H 2 S. Based on the exquisite composition design, the proposed dual-function paper-based fluorescent materials equipped with a smartphone color recognition program concurrently realize fast, accurate, and easy real-time monitoring of Cu2+ in drinking water and H 2 S in chicken breast-/shrimp-spoilage, demonstrating an effective detection strategy for the Cu2+ and H 2 S monitoring and presenting the new type of biomass-based platforms for concentrated reflection of drinking water and food safety. [Display omitted] • On-demand platform enabling simultaneously home-detecting Cu2+/H 2 S was proposed. • The platform realizes user-friendly, low-cost, fast-response detecting of Cu2+/H 2 S. • The platform achieves real-time monitoring of drinking-water and meat-storage safety. • The study provides effective tactics for the integrated Cu2+ and H 2 S home-detecting. [ABSTRACT FROM AUTHOR]

Liquid penetration in porous cellulosic materials is crucial in many technological fields. The complex geometry, small pore size, and often fast timescale of liquid uptake makes the process hard to capture. Effects such as swelling, vapor transport, film flow and water transport within cellulosic material makes transport deviate from well-known relations such as Lucas-Washburn and Darcy's Law. In this work it is demonstrated how Ultra-Fast Imaging NMR can be used to simultaneously monitor the liquid distribution and swelling during capillary uptake of water with a temporal- and spatial resolution of 10 ms and 14.5–18 μm respectively. The measurements show that in a cellulose fiber sheet, within the first 65 ms, liquid first penetrates the whole sheet before swelling takes place for another 30 s. Furthermore, it was observed that the liquid front traps 15 v% of air which is slowly replaced by water during the final stage of liquid uptake. Our method makes it possible to simultaneously quantify the concentration of all three phases (solid, liquid and air) within porous materials during processes exceeding 50 ms (5 times the temporal resolution). We hence believe that the proposed method should also be useful to study liquid penetration, or water diffusion, into other porous cellulosic materials like foams, membranes, nonwovens, textiles and films. [Display omitted] [ABSTRACT FROM AUTHOR]

• Preparation of dual functional humidity humidity-sensitive paper using sustainable nanoclay and beeswax. • Increment of actuation degree up to 110° (30 %RH) from 40° (90 %RH). • Able to detect humidity from changes in electrical resistances (150-700kΩ). A highly humidity-responsive paper can detect moisture or OH-attached molecules at the sub-micron or nano level range. Applying hydrophilic nanoclay as an active material for water sensing would reduce the fabrication cost while remaining environmentally friendly. In this communication, we report the preparation of a nanoclay-inspired dual-responsive smart film that can signal humidity levels from mechanical and electrical responses. The paper will bend as the nanoclay layer swells whereas the resulting bending strain will trigger the electrical resistance changes in the hydrophobic electrically conductive graphite-beeswax layer. [ABSTRACT FROM AUTHOR]

Polyurethane elastomer (PUE) composites were synthesized with a low additive content of waste natural cellulosic fibers from office paper. A new technology combining prepolymer method with physical blending and modification was adopted. The results showed that cellulosic fibers were covalently bonded to polyurethane molecular chains and served as a cross-linking agent making the degree of phase separation decrease. Even so, the lowest additive content of cellulosic fibers (1 wt%) in this work could make polyurethane still hold a certain degree of phase separation. Besides, thermal stability of polyurethane was improved from 288 to around 300 °C even at the low cellulosic fibers content. PUE with 3% cellulosic fibers had the better interfacial compatibility between cellulosic fibers and polyurethane causing the greater thermal reinforcement. PUE with 4% and 5% cellulosic fibers had the worse interfacial compatibility generating the better damping capacity indicating that cellulosic fibers could improve damping performance of polyurethane, especially polyurethane with 5 wt% fibers. It meant that cellulosic fibers had a potential application in damping materials. [ABSTRACT FROM AUTHOR]

Herein, we report on the preparation of novel cellulose-PEG biohybrid papers with wet strength properties. The biohybrid paper sheets are obtained using a two-step procedure where ω- or α, ω-azide functionalized PEG chains are anchored onto alkyne-functionalized wood fibers through CuAAC ligation in mild and aqueous conditions. The incorporation of the PEG grafts mostly occurs at the periphery of the cellulose fibers and degrees of substitution up to 0.028 are obtained. The presence of PEG grafts significantly increases the tensile, burst and tear strength properties in the wet state, the reinforcement being more pronounced for fibers grafted with α,ω-azide PEG. This reinforcement is consistent with a relatively sparse hetero-crosslink reaction creating inter-fiber covalent bonds and forming a cellulose network within the cell wall. [ABSTRACT FROM AUTHOR]

The fracture process in two fiber network materials, a low- and a high-density paper, is analyzed experimentally and numerically. The high-density paper is able to localize continued fracture to very small defects while a rather large defect is required in the low-density paper. Whereas the high-density paper has a homogeneous and limited variation in local mass density, the low-density paper is substantially more heterogeneous and has a higher local mass density variation. It is hypothesized that these fairly large regions of lower mass density govern the fracture process in paper and similar fiber network materials. A nonlocal fracture model is applied to describe and capture this length scale phenomenon and intents to simulate forces bridged over distant regions in the material via connected fibers. The suggested fracture hypothesis is consistent with experiments and hence offers an explanation to why network materials with different mass density variation may fracture differently. [ABSTRACT FROM AUTHOR]

During the last two decades, cellulose nanofibres (CNF) have emerged as a promising, sustainable reinforcement with outstanding potential in material sciences. Though application of CNF in papermaking is recent, it is expected to find implementation in the near future to give a broader commercial market to this type of cellulose. The present review highlights recent progress in the field of the application of cellulose nanofibres as additives in papermaking. The effect of CNF addition on the wet end process is analysed according to the type of pulp used for papermaking. According to the literature consulted, improvement in paper’s overall properties after CNF addition depended not only on the type and amount of CNF applied, but also in the pulp’s origin and treatment. Bulk and surface application of CNF also presented significant differences regarding paper’s final properties. This review also revises the mechanisms behind CNF reinforcing effect on paper and the effect of chemically modified CNF as additives. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO)/cellulose paper was prepared by adding aqueous dispersion of GO into cellulose fiber pulp in a traditional papermaking procedure. Cationic polyacrylamide (CPAM) was added as a mordant to induce the self-assembly of GO layers on the fiber surfaces. The surface morphology, mechanical properties and gas permeability of GO/cellulose paper with varying GO contents were investigated by scanning electron microscopy (SEM), tensile test, burst test, tear test and densometer. It was found that CPAM could prevent the self-aggregation of GO in fiber matrix and increase the loading efficiency of GO to up to 16 wt% without sacrificing the mechanical performances of the paper. This finding permitted the large scale preparation of GO/cellulose paper with high doping amount of GO, which exhibited dense and compact geometry and low gas permeability ideal for potential packaging applications. [ABSTRACT FROM AUTHOR]

Paper, a readily available renewable resource, comprises of interwoven cellulosic fibers, which can be functionalized to develop interesting low-cost adsorbent material for water purification. In this study, polyethyleneimine (PEI)-functionalized paper was used for the removal of hazardous pollutants such as Au and Ag nanoparticles, Cr(VI) anions, Ni 2+ , Cd 2+ , and Cu 2+ cations from spiked water samples. Compared to untreated paper, the PEI-coated paper showed significant improvement in adsorption capacities toward the pollutants investigated in this study. Kinetics, isotherm models, pH, and desorption studies were carried out to study the adsorption mechanism of pollutants on the adsorbent surface. Adsorption of pollutants was better described by pseudo-second order kinetics and Langmuir isotherm model. Maximum adsorption of anionic pollutants was achieved at pH 5 while that of cations was at pH > 6. Overall, the PEI-functionalized paper showed interesting Langmuir adsorption capacities for heavy metal ions such as Cr(VI) (68 mg/g), Ni 2+ (208 mg/g), Cd 2+ (370 mg/g), and Cu 2+ (435 mg/g) ions at neutral pH. In addition, the modified paper was also used to remove Ag-citrate (79 mg/g), Ag-PVP (46 mg/g), Au-citrate (30 mg/g), Au-PVP (17 mg/g) nanoparticles from water. Desorption of NPs from the adsorbent was done by washing with 2 M HCl or thiourea solution, while heavy metal ions were desorbed using 1 M NaOH or HNO 3 solution. The modified paper retained its extraction efficiencies upon desorption of pollutants. [ABSTRACT FROM AUTHOR]

Abstract: A new composite paper with high photocatalytic performance has been successfully manufactured by introducing titania-anchored porous silica into cellulose fibres. The silica particles with an average size of 700nm were synthesized via CaCO3 templating and further employed as support to grow titania nanoparticles (5.2nm) by sol–gel synthesis with variable weight ratios. The photocatalytic materials have been characterized using various techniques including BET, XRD, Raman spectroscopy, SEM and TEM+EDX+ED microscopies. The composite TiO2/SiO2 particles have been further introduced in bulk paper to generate highly active photocatalytic TiO2-loaded papers. The activity of the papers has been demonstrated in the room-temperature degradation of ethanol (50–200ppm) under UV irradiation, showing a comparable activity to that of commercial TiO2-coated papers. The effect of the main textural variables during papermaking on the photocatalytic performance are discussed in detail. [Copyright &y& Elsevier]

Highlights: [•] No external catalyst is required for citric acid crosslinking of cellulosic fibres. [•] We propose a mechanism for self-catalysed esterification of cellulosic fibres. [•] Crosslinking is facilitated by high curing temperature and citric acid dose. [•] Crosslinking increases linerboard compressive strength at high humidity. [•] Crosslinking extends lifetime of corrugated boxes under cycling high humidity. [ABSTRACT FROM AUTHOR]

Highlights: [•] CNFs-based flexible transparent conductive paper was successfully prepared. [•] Optoelectronic properties of paper can be controlled by the times of LbL assembly. [•] Transparent conductive paper has good optoelectronic properties. [•] Transparent conductive paper has excellent flexibility and mechanical properties. [ABSTRACT FROM AUTHOR]

Abstract: Cellulose fiber has been modified by mechanical and chemical means in order to improve paper properties, which respond to moisture and temperature. When the cellulose is first refined and then etherified using hydroxypropylation under dry conditions, the paper sheets prepared from the hydroxypropylated cellulose show improved elongation. When the level of hydroxypropylation is high enough, the paper sheets also become transparent. Additionally, the effect of cellulose activation using different mechanical methods has been compared by esterification reactions. It is shown that removal of water is the most crucial step for the esterification reactions while other methods have a lesser impact. The paper sheets prepared from the esterified cellulose fibers show an increase in contact angles and high hydrophobicity. [Copyright &y& Elsevier]

Abstract: A silver nanoparticle colloid was prepared by a modified Tollens method using d-glucose as the reduction agent. The obtained nanoparticles were used for the modification of pine, linter and recycled cellulose fibers. Although the silver contents were relatively low (0.05–0.13wt.%), the cellulose-sheets prepared from the modified fibers show improved mechanical and viscoelastic properties. The tensile index (strength) increased with up to 30% in comparison to the index of the sheets obtained from the untreated fibers. The influence of the nanoparticles on the viscoelastic properties of the cellulose sheets was investigated by dynamic mechanical analysis (DMA) in the temperature range from −120 to 20°C and with a force frequency of 100Hz. A broad relaxation transition positioned at −80°C was observed in the loss modulus spectrum of all the cellulose sheets, while the Ag-modified sheets exhibited higher storage moduli values in the whole temperature range. The antimicrobial activity tests show that the pine, silver and recycled cellulose fiber sheets with silver nanoparticles can be successfully employed to prevent the viability and growth of the common pathogens Staphylococcus aureus, Escherichia coli and Candida albicans. [Copyright &y& Elsevier]

Abstract: A commercial rice paper (RP) is used for the first time as a separator membrane in lithium-ion batteries. It consists of interpenetrating cellulose fibers with a diameter of about 5–40μm to form a highly porous structure. The RP is found to be electrochemically stable at a potential below 4.5V vs. Li+/Li. Several kinds of electrode materials including graphite, LiFePO4, LiCoO2 and LiMn2O4 are used to test the compatibility of the RP in Li-ion batteries and to compare with a commercial polypropylene/polyethylene/polypropylene separator membrane. The RP separator with the same thickness gives rise to a lower resistance than the commercial separator. Due to the wonderful flexibility, high porosity, low cost and excellent electrochemical performance of the RP membrane, it is promising to partially replace commercial separators in lithium-ion batteries for low power applications. [Copyright &y& Elsevier]

Abstract: The mechanism of the retention of TiO2 filler particles on cellulose fibers has been under discussion for several decades; the diverse models, and the properties of the components relevant to retention, are critically reviewed in the first part of this study. In addition, two new quantitative models of detachment of polyelectrolyte-bonded colloidal particles from the fiber are also examined; one of these is based on DLVO theory for description of the influence of particle charge and polyelectrolyte amount, and should hold true at low shear rates and high bond strengths. The other model applies Kolmogorov''s theory of isotropic turbulence in order to relate the work necessary for particle detachment to the turbulent energy of pulp in paper machines, i.e., under high shear rate and low bond-strength conditions. The second model is based on analysis of fluid dynamics in paper machines, and is formulated here for laboratory tests using the Dynamic Drainage Jar (DDJ). A series of laboratory-prepared TiO2 fillers covering a range of isoelectric points (ieps) from pH 4.4 to pH 7.5, additionally with poly-(aminoamide)-epichlorohydrin (PAE) and polyethyleneimine (PEI) as retention aids, and commercially milled cellulose, were used in the experimental part of the study. The retention-aid demand of fillers and cellulose for surface neutralization was determined using electrokinetic methods. Filler retention on cellulose was measured in the DDJ for various stirrer speeds and amounts of retention aid, with the amount of filler not exceeding that for a monolayer on the fiber. Without retention aids, neutral filler particles are accordingly completely retained on the negative fiber, whereas negatively charged particles are not. The retention of the latter can, however, be steadily improved by increasing polyelectrolyte concentration. Retention of colloidal particles in paper manufacturing is therefore determined by a delicate balance between H-bridging and van der Waals forces, on the one hand, and Coulomb forces, on the other, resolving the long-enduring debate concerning the relative influence of bridging and patch-charge mechanisms. Results obtained using PAE also indicate that polyelectrolytes initially spread over the filler surface are redistributed into the gap between the filler particle and the fiber during filler attachment. [Copyright &y& Elsevier]

• Bricks made by bottom ashes, cellulose fibers and clay have been successfully made and tested. • Optimum blends are made of 70% of clay, 25% of bottom ashes and 5% of cellulose fibers. • The so made bricks comply mechanical requirements and are 20% lighter. • Lower thermal conductivity and equal specific heat capacity is achieved. • Toxicity analysis abides by standards in force. The paper and pulp industry (PPI) is permanently searching for new ways of managing its residues due to the increasing pressure of new environmental concerns and policies adopted worldwide. In addition, the manufacturing of construction materials such as fired clay bricks (FCBs) is also facing the transformation of its traditional market, which is asking for new materials with a lower environmental footprint but equal or even better technological properties. In considering the large mass flows related to both the PPI and FCB industries, several researchers have pointed out the feasibility of replacing clay by residues produced by PPI. However, these approaches have always considered the replacement of a single residue rather than the addition of several new ones. Conversely, by using both residues at once, the overall FCB performance is improved and the feasibility of this circular economy approach is eased. For instance, the addition of woody fibres increases thermal resistance but reduces mechanical strength. Conversely, the addition of ashes produced by PPI improved the mechanical strength by reducing the thermal resistance due to the increasing content of fluxing agents which improve the fired clay matrix structure. For this reason, this paper explores the technological properties achieved by replacing clay with both ashes and fibres provided by PPI in an integrated approach. By following industrial procedures, the so made fired clay bricks (with 20% of ash and 5% of fibres) meet the standard and show approx. 20% less thermal conductivity, with the same thermal capacity and a density reduction of more than 15%. [ABSTRACT FROM AUTHOR]

Cellulosic nanomaterials are in the focus of academia and industry to realize light-weight biobased materials with remarkable strength. While the effect is well known, the distribution of these nanomaterials are less explored, particularly for paper sheets. Here, we explore the 3D distribution of micro and nanosized cellulosic particles in paper sheets and correlate their extent of fibrillation to the distribution inside the sheets and subsequently to paper properties. To overcome challenges with contrast between the particles and the matrix, we attached probes on the cellulose nano/microparticles, either by covalent attachment of fluorescent dyes or by physical deposition of cobalt ferrite nanoparticles. The increased contrast enabled visualization of the micro and nanosized particles inside the paper matrix using multiphoton microscopy, X-ray microtomography and SEM-EDX. The results indicate that fibrillary fines enrich at pores and fiber-fiber junctions, thereby increasing the relative bonded area between fibers to enhance paper strength while CNF seems to additionally form an inner 3D network. [ABSTRACT FROM AUTHOR]

• Hydrogen bonds formed in the LTTMs enabled the removal of lignin from EFB. • Clear separation of precipitated lignin was observed in EFB strands after washing. • EFB powder showed stronger molecular bonding of pulp than EFB strands. • Paper formed from cactus based LTTMs-delignified EFB had less void space and pores. The aim of this work was to recover the cellulose fibers from EFB using low-transition-temperature-mixtures (LTTMs) as a green delignification approach. The hydrogen bonding of LTTMs observed in 1H NMR tends to disrupt the three-dimensional structure of lignin and further remove the lignin from EFB. Delignification process of EFB strands and EFB powder were performed using standard l -malic acid and cactus malic acid-LTTMs. The recovered cactus malic acid-LTTMs showed higher glucose concentration of 8.07 mg/mL than the recovered l -malic acid LTTMs (4.15 mg/mL). This implies that cactus malic acid-LTTMs had higher delignification efficiency which led to higher amount of cellulose hydrolyzed into glucose. The cactus malic acid-LTTMs-delignified EFB was the most feasible fibers for making paper due to its lowest kappa number of 69.84. The LTTMs-delignified EFB has great potential to be used for making specialty papers in pulp and paper industry. [ABSTRACT FROM AUTHOR]

Abstract: We have developed flexible top emission organic light-emitting devices by using sputtered Ni films on the parylene coated copy paper substrates. The Ni film grew through the coalescence of the Ni islands nucleated on the cellulose fiber patterns. The parylene, acting as a buffer layer for preventing water absorption, affected the morphological and electrical characteristics of the deposited Ni films. The flexible top emission diode device composed of Ni anode and Ca/Ag semitransparent cathode exhibited a luminance of ∼1 cd/m2 at a driving voltage of 14.5 V. [ABSTRACT FROM AUTHOR]