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• BC/ZnO nanocomposite strengthens paper and improves aging resistance. • The nanocomposite imparts antifungal properties to paper. • The nanocomposite helps in deacidification of paper. Paper, commonly used as an information carrier, can become acidified and brittle over time. In this study, 0.3 % bacterial cellulose (BC) composite with 1.0% zinc oxide (ZnO) nanoparticles was prepared and used to coat brittle book paper for deacidification and consolidation. The BC/ZnO nanocomposite was characterized using zeta potential, micro morphology, elemental mapping, X-ray photoelectron spectra, Fourier transform infrared, and thermogravimetric analyses. The results indicated that the composite exhibited good stability. ZnO nanoparticles were bonded to the hydroxyl groups on BC, enhancing the thermal stability of BC. The composite was uniformly sprayed on the paper surface, and the mechanical properties, color difference, readability, pH, and micromorphology of the paper samples were examined before and after the treatment. The BC/ZnO nanocomposite exhibited good deacidification and consolidation effects on paper samples with low impact on the original paper appearance. Moreover, the BC/ZnO nanocomposite showed a good inhibitory effect on fungi growth on paper. [ABSTRACT FROM AUTHOR]

Colored paper is an important industrial paper grade that has applications in various industrial sectors. The increase in coloring efficiency is a key in decreasing the use of dyes, thus can be considered as a "green" process concept; the coloring efficiency depends on the dye retention and dispersion. This work explores the use of nanocellulose, specifically, TEMPO-oxidized cellulose nanofibers (TOCNF), on the coloring efficiency of the preparation of colored paper. Two dyes (i.e. direct blue GL and reactive red 195 (RR195)) were used. Thanks to the large specific surface area and abundant active sites of TOCNF, its use largely improves the direct blue GL retention during the process. The coloring difference (∆E* ab) reached 5.334 with the addition of 13.6 wt% TOCNF and 1.8 wt% direct blue GL in the pulp furnish. The functional group in the dye is a vital factor in determining the dye retention when one chooses TOCNF to enhance the coloring efficiency in the production of colored paper. Furthermore, TOCNF significantly improved the strength properties of both direct blue GL and RR 195 dyed papers. This work demonstrates the potential of nanocellulose in the production of colored paper in improving the coloring efficiency, thus decreasing the environmental impact of the manufacturing process. [Display omitted] • Nanocellulose (i.e. TOCNF) adopted for colored paper preparation • Coloring efficiency improved by TOCNF due to the dye retention improvement • -COO− in TOCNF deteriorating its combination with negatively-charged dye [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]

The high demand for flexible electroconductive elements, such as organic coatings, is associated with the development of IoT devices, wearable health monitoring devices, and similar devices. To meet cost and environmental standards, the ideal coating should use the richness of nature, be biodegradable, and be water soluble to avoid the use of harmful organic solvents. All of these criteria are met by the composite coating consisting of sodium lignosulfonate (SLS) and multiwall carbon nanotubes (MWCNTs). Furthermore, the SLS/CNT coating on paper substrates is highly electroconductive, hydrophobic, and resistant to annealing, high humidity, bending, and scratching. The electrical conductivity of the SLS/CNT coating varies depending on the substrate used, but it is highly conductive and resistant on all substrates tested. Most importantly, due to the use of abundant and mass produced and cheap materials, the price of a coating containing 77 wt% SLS and 23 wt% CNT, with a sheet resistance of 113 Ω/sq is estimated to be around 2.05 EUR/m2. This coating can be especially beneficial for large-scale applications, such as heating films. [Display omitted] • SLS is an affordable and readily available stabilizer for CNT dispersion in water. • SLS/CNT creates a highly conductive coating on cellulose substrates. • The SLS/CNT coating on paper has potential applications as cost-effective sensors or heaters. • The conductivity of the coating is influenced by the properties of the substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sonication improves the absorption of metallic salt in the paper. • Ultrasound catalyzes the synthesis of metallic nanoparticles. • A longer sonication time during salt absorption increases the number of nanoparticles obtained. • Nanoparticles obtained by sonochemistry are an easy and reproducible method to modify paper. This work focuses on a systematic method to produce Ag, Cu, and Ag/Cu metallic nanoparticles (MNPs) in situ assisted with ultrasound on cellulose paper. By tuning the concentration of AgNO 3 and CuSO 4 salt precursors and ultrasound time, combined with a fixed concentration of ascorbic acid (AA) as a reducing agent, it was possible to control the size, morphology, and polydispersity of the resulting MNPs on cellulose papers. Notably, high yield and low polydispersity of MNPs and bimetallic nanoparticles are achieved by increasing the sonication time on paper samples pre-treated with salt precursors before reduction with AA. Moreover, mechanical analysis on paper samples presenting well-dispersed and distributed MNPs showed slightly decreasing values of Young's modulus compared to neat papers. The strain at break is substantially improved in papers containing solely Ag or Cu MNPs. The latter suggests that the elastic/plastic transition and deformation of papers are tuned by cellulose and MNPs interfacial interaction, as indicated by mechanical analysis. The proposed method provides insights into each factor affecting the sonochemistry in situ synthesis of MNPs on cellulose papers. In addition, it offers a straightforward alternative to scale up the production of MNPs on paper, ensuring an eco-friendly method. [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]

Gaseous acetic acid is formed under conditions of storage of historic paper objects. Its presence not only promotes hydrolytic cleavage of cellulose, but also causes acetylation of the cellulosic material to very small degree. The acetylation reaction proceeds under ambient conditions and without catalyst. Different analytical methods were used to prove the presence of organic acetates on cellulosic paper matrices. DESI-MS in combination with 2H-isotopic labeling showed the presence of sugar fragments with different acetylation patterns. A method based on Zemplen saponification was applied and worked also in the presence of a large excess of acetic acid and/or inorganic acetates. The acetylation effect was quantified for model papers and original, naturally aged paper samples. While cellulose acetylation was clearly proven to be another general pathway of paper aging, further studies of this acetylation phenomenon are needed with regard to conservational aspects and suitable paper storage conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

• 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]