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Purpose: This study aims to determine the ink removal efficiency of papers with different recycling numbers and to examine some electrophotographic printing properties. Design/methodology/approach: The base papers prepared according to the INGEDE 11p standard are subjected to six recycling stages (RS) under equal conditions. The physical-optical properties of the papers obtained at the end of each RS are measured and CMYK (cyan, magenta, yellow, key) color measurement scales are printed on each paper with electrophotographic printing. Color measurements of the printed papers are measured using the X-Rite eXact spectrophotometer, adhering to the ISO 13655:2017 standard. According to the measurement results of the optical properties, the ink removal efficiency of each recycling step is determined as a percentage (%) using some formulas. Findings: As general, according to DEMLab and IERIC data, it is determined that the ink removal efficiency increased as the recycling repetition increased. In DEMf factor values, the highest deinking efficiency is obtained after the fourth RS. There is no significant difference between the printing properties of the samples. Originality/value: It has been a matter of curiosity that papers lose their properties after how many RS. Many studies have been carried out on this subject and it has been presented by experimental methods that the printability properties of papers increase or decrease after which RS. This study can be a pioneer for future studies. [ABSTRACT FROM AUTHOR]

Traditionally, cellulose nanofiber (CNF) production has primarily relied on virgin cellulose sources. Yet, the shift to using paper mill sludge (PMS) as a source for CNF underscores the significance of reusing and recycling industrial byproducts. PMS contains significant amounts of cellulose that can be extracted as a raw material. The purpose of present study is to provide a sustainable approach to PMS utilization as a paper coating additive in the cellulose nanofibrils (CNFPMS) form via simply scalable wire-wound rod coating method. The effect of CNFPMS additive amounts at two coating layers on microstructure and surface properties of coatings such as porosity, air permeability surface roughness and optical properties such as brightness, gloss and CIE L*a*b* is studied, which they can also provide insight for the eventual print performance. Results indicated that the obtained CNFPMS in paper coating shows 52% decrease in porosity, presenting significant improvement in the coating microstructure. The marginal increase in permeability coefficient and surface roughness, 54% and 10%, respectively, suggests improving color reproduction and preventing color density losses. Optical analysis showed slight decrease in brightness and gloss, as was expected. Notably, the lightness was improved, which also indicates increasing color gamut volume in printing applications. As a result, the current work offers a sustainable approach to manage PMS for use in paper coatings as a high-value-added material. [ABSTRACT FROM AUTHOR]

Mineral paper, a synthetic paper‐like material primarily composed of ground calcium carbonate (CaCO3) and a small amount of high‐density polyethylene (HDPE), has emerged as an important alternative to traditional paper and board due to the increasing demand for pulp and paper and the shortage of trees and fibrous material in many regions worldwide. This study aimed to investigate the impact of accelerated weathering and aerobic biodegradation on three different types of mineral papers. The specimens underwent 1000 h of accelerated weathering using a Gardner weathering device and were also buried in soil at a depth of 5 cm for 3 months with regular watering conditions for biodegradability testing. Physico‐chemical characterizations such as optical (whiteness), surface (roughness, contact angle, and paper topography), and chemical properties of the samples were studied before and after the artificial weathering and biodegradation tests. The results revealed a visible color change (darkening) in mineral papers, with an increase in HDPE content leading to a darker color after weathering and biological degradation. However, there were no significant differences in the color change between weathering and soil‐burial tests. The biodegradability test resulted in a decrease in ash content due to the demineralization process. All samples' surface roughness was reduced after weathering and biodegradation tests. The FT‐IR and EDS analyses confirmed the presence of calcium, carbon, and oxygen elements in all three samples, indicating a large amount of calcium carbonate in the mineral papers. The scanning electron microscopy (SEM) images showed the creation of micro holes and cracks on the surface of the samples after weathering and biodegradation. Overall, the soil‐burial test showed more degradation than the weathering test. Highlights: The influence of weathering and biodegradation of mineral papers were studiedAfter soil‐burial test, the ash content decreased due to the demineralizationAfter weathering, micro cracks were created on the surface of the samplesThe degradation of the soil‐burial test was more than the weathering testMineral papers most likely contain carbonate calcium and HDPE [ABSTRACT FROM AUTHOR]

The effect of bamboo virgin pulp addition to the recycled pulp in enhancing the recycled paper's mechanical properties was evaluated. Malaysian bamboo virgin pulp used in this research were Bambusa vulgaris (Aur bamboo), Gigantochloa levis (Beting bamboo), and Gigantochloa scortechinii (Semantan bamboo). The addition of 2.5, 5, 7.5, and 10 wt% of bamboo virgin pulp improved the burst index, folding endurance, tearing index, and tensile index of the recycled paper from 2.27 to 3.17 kPa.m2/g, 7 to 15 double folds, 5.98 to 8.27 mN.m2/g, and 24.86 to 32.40 Nm/g, respectively. These were equivalent to the increment percentage for burst index, folding endurance, tearing index, and tensile index at the range of 6.61 to 39.65%, 28.57 to 114.29%, 15.72 to 38.59%, and 10.50 to 33.87%, respectively. The application of bamboo virgin pulp is very promising in improving the recycled paper's mechanical properties and this could be further extended in enhancing the other properties such as physical and optical paper properties. [ABSTRACT FROM AUTHOR]

Simultaneous effects of using cellulose nanocellulose and chemical pulp in paper money were studied with bottom combers cotton pulp. The bottom combers pulp and chemical pulp were prepared in a factory that produced durable paper, and their products were transferred to the laboratory. The nanocellulose was prepared by Nano Novin Polymer Co. and was consumed at 4 levels, i.e., 0%, 0.3%, 0.6%, and 0.9%. After commixing the pulp with the nanocellulose at the identified percentages, handsheets of 90 g∙m-2 papers were produced. The results showed that by increasing the amount of nanocellulose, up to 0.9%, the tensile strength index, burst strength index, tear strength index, and folding endurance increased 22.7%, 38.9%, 7.7%, and 348%, respectively, when compared with the control sample. Enhancement via nanocellulose up to 0.9% increased the surface smoothness up to 7.9% compared with the control sample, while the air resistance and Cobb decreased 69% and 7.9% in comparison with control sample, respectively. By increasing the nanocellulose content up to 0.9% the opacity increased 0.7%; moreover, the brightness and whitening decreased 3.5% and 10.6, respectively. The scanning electron microscopy results indicated that enhancement via nanocellulose decreased the air resistance. [ABSTRACT FROM AUTHOR]

In this study, electrophotographic printing and inkjet printing systems were applied to some commercial A4 office papers and their effects on print quality were determined. It is to evaluate the print quality by determining the test parameters that measure the print quality by applying electrophotographic printing and inkjet printing systems to some commercial office papers that have determined the surface properties and optical properties supplied from the market. Print quality was measured by testing with parameters such as delta gloss 60°, print lightness, print chroma, print density. As a result of the tests determined for print quality; print density values were low in A4 office papers with high roughness and porosity values, and the specular gloss values of the samples decreased in both printing applications. In electrophotographic printing; it was determined that darker colors formed with print lightness parameter, and the color scale increases in two-sided printing with print chroma values. It was determined that the color scale of print chroma values increased in two-sided prints. It was determined that mostly some commercial office papers were positively affected by printing on one side in inkjet printing and by printing on two-sided in electrophotographic printing. [ABSTRACT FROM AUTHOR]

A novel paper multifunctional protective solution was prepared by mixing berberine modified trimethoprimed carboxymethyl cellulose (TMP-DCMC-BBR), KH-791 modified nano-SiO2 (KH791-SiO2) and hydroxypropyl starch phosphate (HPDSP), and the mechanical properties, optical properties, antibacterial properties, aging resistance, acid and alkali resistance of the paper coated with the protective solution were investigated. It is shown that the paper coated with the multifunctional protective liquid showed good mechanical properties, and has little influence on optical properties of the paper. At the same time, it had good antibacterial properties, aging resistance and acid and alkali corrosion resistance, and there is no obvious change in paper appearance, no decolorization and ink diffusion, which is in line with the principle of "repairing the old as the old and keeping the original appearance". Moreover, the compound solution has certain reversibility and can absorb a certain degree of ultraviolet rays, so as to weaken the damage of ultraviolet rays to the paper. It is an ideal multifunctional protective liquid for paper and has broad application prospects in paper protection. [ABSTRACT FROM AUTHOR]

The manufacturing of paper with new functional properties is a current problem today. A method of modifying the surface layer of paper by the partial dissolution of cellulose on its surface is proposed. N-Methylmorpholine-N-oxide (NMMO) is proposed for use as a solvent, the regeneration of which provides an environmentally friendly process. It was shown that among the possible hydrate forms of the solvent, the monohydrate and higher-melting forms are optimal for modifying the paper surface. The temperature–time modes of processing were revealed and the weight gain and density increase in the course of modification were estimated. The structural and morphological features of the original and modified paper were studied by X-ray imaging and scanning microscopy. The NMMO surface treatment makes it possible to vary the air permeability of the paper, making it practically non-permeable. The capillary and pore system were radically transformed after the partial dissolution of cellulose and its coagulation, as the formed cellulose film isolates them, which leads to a decrease in surface absorbency. The processing conditions allowing for the optimization of the optical and strength properties of the modified paper samples are revealed. The resulting paper with a modified N-methylmorpholine-N-oxide surface layer can be used for printing valuable documents. [ABSTRACT FROM AUTHOR]

The aim of this study is to compare laserjet printing and inkjet printing properties on recycled papers. In the study, we recycled reference papers prepared in accordance with the INGEDE 11p standard. After recycling the papers, we produced test papers in the laboratory environment and examined the physical and optical properties of the obtained papers. We applied calendering process at 100 oC temperature and 20 bar pressure on the obtained test papers. After this process, we printed trigromy color measurement scales with inkjet and laserjet printers on the test papers obtaine Finally, using the spectrophotometer, we determined the printing properties of both print types. When we examined the results, we determined that in most of the printability parameters, laserjet had a superior performance and was a more usable printing system. For example, while the inkjet cyan density value is 0.94, the laserjet is 1.05. While M + Y trapping value was 28.23 in inkjet, it was 92.20 in laserjet. For example, we found the Gloss value as 2.53 in inkjet and 4.23 in laserjet. While inkjet cyan print chroma value is 44.03, it is 48.09 in laserjet. In addition, we determined that laserjet printing reached a wider area as a color gamut. Based on the color measurement results of both printing types, we have determined that the printability of recycled papers is reasonable. We have determined with experimental results that laserjet printing produces better quality prints in a short time, especially in the office environment. [ABSTRACT FROM AUTHOR]

The effects of nanoclay were studied relative to the physical, mechanical, optical, and morphological properties of chemimechanical pulping papers. Nanoclay was incorporated at 0%, 2%, 4%, 6%, 8%, or 10%. To increase the retention, 1% cationic starch was used in all test papers. Handsheets (60 g/m2 in weight) were tested to determine their physical, mechanical, optical, and morphological properties. Up to 2% nanoclay increased the tensile strength; at values greater than 2%, the tensile strength decreased. The addition of up to 4% nanoclay increased roughness; between 4% and 10% nanoclay, roughness decreased. With 10% nanoclay, the tear strength, burst strength, and brightness decreased, but the air resistance, opacity, and yellowness increased. Scanning electron microscopy showed that the nanoclay filled the pore spaces between fibers, thus increasing air resistance. X-ray diffraction patterns indicated an intercalated structure. [ABSTRACT FROM AUTHOR]

This research aimed to investigate the efficiency of crude xylanase–pectinase in pulping of sugarcane bagasse. Optimum biopulping was obtained, using xylanase–pectinase dose 200–60 IU/g, bagasse/liquid ratio 1:10 and 1.0% Tween 80 concentration at 55 °C temperature, pH 8.5 and period of treatment 180 min. Treatment of sugarcane bagasse samples with these enzymes generated pulp with lower rejections (58.76%), total solids (12.64%), kappa number (47.77%), higher screened pulp yield (10.66%), along with enhanced optical and physical properties, in comparison with a chemical pulp. Bagasse biopulping resulted in a 13% decrease in alkali dose to obtain the optical and physical properties similar to those achieved under the 100% alkali dose. The breaking length, burst factor, tear index, double fold, gurley porosity and viscosity were improved by 15.19, 37.64, 2.47, 37.77, 35 and 23.17%, respectively, after bleaching treatment of biopulped samples. Thus, enzymatic pulping is an eco-friendly environmentally sustainable approach, since it reduces the use of pulping chemicals and simultaneously improves the paper quality. This is the first report, showing pulping of sugarcane bagasse, with crude xylanase–pectinase, produced by an isolate. [ABSTRACT FROM AUTHOR]

This study was aimed to examine the effects of basic properties, fiber morphological properties, strength properties, wettability and optical properties on offset printing of office papers. Widely used office papers with different brands were obtained from Istanbul-Turkey. Technical characteristics of papers; basic properties, strength properties including tensile, burst, tear, and Z direction tensile strength and optical properties such as gloss, whiteness, opacity, and wettability tests were determined according to TAPPI and ISO standards. The results obtained by the tests are as follows; i) there is a great difference in water resistance between the top and the lowest values (207 %), ii) there is little difference between the highest and the lowest brightness value (3.8 %), other papers values have close to each other, iii) in the printing process there is a little difference between the highest, and the lowest gloss values (36.7 %), although the others are close iv) the highest and lowest values in CIE C* showed that it ranged from the narrowest color gamut to the widest color gamut. By applying the widely used offset printing process to commercially produced office papers, the quality levels were evaluated to raise awareness of consumers and sellers. [ABSTRACT FROM AUTHOR]

This study elaborates the application of composite films based on nanofibrillated cellulose obtained from cotton linters oxidized in the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)/NaBr/NaClO system, with the use of CaCО3 and/or Al(OH)3 as fillers, and glycols as plasticizers, to improve the mechanical, optical, and sorption properties of paper. The paper coating with nanofibrillated cellulose-based films, without additional adhesive, depending on the concentration of nanofibrillated cellulose in the dispersion and the type of filler, improves the mechanical properties of paper, and decreases sorption properties, while no significant changes were observed in optical properties compared to the initial papers. [ABSTRACT FROM AUTHOR]

Layered metal chalcogenide materials are exceptionally appealing in optoelectronic devices thanks to their extraordinary optical properties. Recently, their application as flexible and wearable photodetectors have received a lot of attention. Herein, broadband and high-performance paper-based PDs were established in a very facile and inexpensive method by rubbing molybdenum disulfide and titanium trisulfide crystals on papers. Transferred layers were characterized by SEM, EDX mapping, and Raman analyses, and their optoelectronic properties were evaluated in a wavelength range of 405–810 nm. Although the highest and lowest photoresponsivities were respectively measured for TiS3 (1.50 mA/W) and MoS2 (1.13 μA/W) PDs, the TiS3–MoS2 heterostructure not only had a significant photoresponsivity but also showed the highest on/off ratio (1.82) and fast response time (0.96 s) compared with two other PDs. This advantage is due to the band offset formation at the heterojunction, which efficiently separates the photogenerated electron–hole pairs within the heterostructure. Numerical simulation of the introduced PDs also confirmed the superiority of TiS3–MoS2 heterostructure over the other two PDs and exhibited a good agreement with the experimental results. Finally, MoS2 PD demonstrated very high flexibility under applied strain, but TiS3 based PDs suffered from its fragility and experience a remarkable drain current reduction at strain larger than ± 0.33%. However, at lower strains, all PDs displayed acceptable performances. [ABSTRACT FROM AUTHOR]

In this study, investigates recycling possibilities of office paper in archive form (stored for at least 5 years). These papers are mostly made by burning. This is to destroy tons of paper raw materials. These papers may be presented with a simple pulping or recycling with small fractionation. This will contribute greatly to the country's economy. The study will also look at the physical and optical properties of these papers. These papers are likely to lose fiber resistance and brightness due to the physical conditions (humidity, temperature) and the mushrooms and insects. In addition, loss of the shine and resistance of the fibers will come to the fore when the ink is removed from these papers. How much of these losses are in the study will be investigated. This will be done in conjunction with a number of applications to compensate for losses. With these operations, tons of waste paper raw materials will be obtained and new waste white office paper will be produced with the desired quality. [ABSTRACT FROM AUTHOR]

Unprinting of paper can reduce multiple life-cycle stages in the recycling of paper to yield significant environmental impact. Laser-unprinting has been demonstrated for uncoated paper but causes significant damage to coated paper. This work explores a scalable optical (non-laser) process for unprinting coated paper. Printed coated paper is exposed to pulsed broad-spectrum Intense Pulsed Light (IPL) from a xenon lamp and the toner is then removed by dabbing gently with an ethanol wipe. While black toner is easily unprinted, unprinting of colored prints (red, blue, green) is best realized by incorporating an initial overprint of black toner. An unprinting throughput on the order of mm2/s is achieved. Three distinct regimes of unprinting are identified based on the extent of toner removal and damage of the paper. The optical properties of the unprinted paper, characterized via UV–Visible spectrophotometry, are correlated to these regimes to understand the potential for in-situ optical process monitoring. Scanning Electron Micrography and Fourier-Transform Infrared Spectroscopy are performed to understand the underlying mechanisms that govern the occurrence of the different unprinting regimes. Further, the potential impact of the developed approach on recycling of paper is discussed in the context of the capabilities of current optical unprinting approaches and the potential elimination of life-cycle stages in conventional paper recycling. • Intense Pulsed Light can scalably unprint toner from coated paper with minimal chemical usage. • Our overprinting approach enables colored prints to be removed as well. • Unprinting throughput of mm2/s is achieved. • Three distinct unprinting regimes exist, depending on process parameters and toner types. • Thermal weakening of toner-coating bonds and cracking are the primary governing mechanisms. [ABSTRACT FROM AUTHOR]

To enhance the strength of paper cultural relics and prolong the life of paper cultural relics, it is an urgent need to prepare new material for preservation and protection of paper. In this paper, chitosan quaternary ammonium salt/HEC-acrylate was synthesized with O-hydroxypropyl trimethyl quaternary ammonium salt chitosan (O-HACC) and Hydroxyethyl Cellulose (HEC)-acrylate emulsion, the synthesized materials has multiple functions, such as deacidification, reinforcement, anti-mildew and antibacterial etc. The synthesized new materials were applied on paper, and their protective effect was evaluated by testing the mechanical and optical properties and antibacterial properties of the paper. The results showed that when the mass concentration of O-HACC was 0.6 %, the tensile strength, folding times and tearing strength of the paper coated with protective solution were improved to a certain extent, while the optical properties and appearance of the paper remained basically unchanged. Meanwhile, the paper also had certain anti-mildew and bacterial resistance. [ABSTRACT FROM AUTHOR]

Mending tears in translucent papers is a challenging task that requires mending materials with specific mechanical and optical properties. Recently, translucent films from microfibrillated cellulose have been suggested as an attractive alternative to traditional repair materials. We prepared custom films from a commercial microfibrillated cellulose suspension and compared their mechanical and optical properties as mending supports with commercially manufactured microfibrillated cellulose films and Japanese tissue. Tear mending of modern and historic translucent paper samples using the custom-made films and Klucel G or isinglass as adhesives showed satisfactory strength and resilience, and accelerated ageing tests yielded acceptable visual results. A case study on a translucent paper document from the collection of The National Archives, UK, is detailed. We conclude that custom-made tear mending materials from commercially available microfibrillated cellulose suspensions present a cost-effective and attractive approach for the mending of translucent papers. [ABSTRACT FROM AUTHOR]

Despite changes in optical and printing properties, the applied coating components on the paper surface have a significant impact on the surface chemistry of office paper. Depending on the use, such as ink penetration for printing and writing papers, an optimal hydrophobic and hydrophilic balance may be beneficial. In this study, several coating components including starch betainate, Pluronics, and precipitated calcium carbonate were employed to coat base paper (paper without any surface treatment). The influence of these components on water penetration was investigated using dynamic penetration. When compared to native starch coated papers, paper coated with starch betainate (a cationic starch ester) showed reduction in hydrophobicity and increased water penetration. Moreover, this effect was further enhanced with the use of Pluronics. Likewise, hydrophobicity decreased as the concentration of starch betainate, precipitated calcium carbonate and Pluronics increased. Furthermore, water penetrated even more quickly when the combination of these components compared with the individual component coatings. [ABSTRACT FROM AUTHOR]

Xylan is the primary hemicellulose in most hardwood species, especially in birch. Research has highlighted the exploitation of xylans as a strengthenhancing additive to paper due to the current trend for the effective utilization of biomass. In this paper, a new pulping process was proposed, which involved the extraction of xylan prior to pulping, followed by the readsorption of the pulp after the final stage in the digester, followed by a suitable bleaching process. The aim of this work was to bleach hardwood kraft pulp (brown pulp) with adsorbed birch xylan via hydrogen peroxide and study the effect of the bleaching parameters on the paper properties. The results showed that the optical properties of paper decreased; however, the mechanical properties increased after the brown pulp adsorbed birch xylan. During the bleaching process, better mechanical properties were obtained with shorter bleaching times and lower bleaching temperatures, initial pHs, and MgSO4 dosages. However, the optical properties were improved as the bleaching time, temperature, initial pH, and MgSO4 dosage were increased. The adsorption of birch xylan could effectively modify the mechanical properties of paper made from brown pulp under various phases. [ABSTRACT FROM AUTHOR]

Reflective liquid crystal displays are attracting attention as portable information systems because of zero- or extremely low power consumption. In this study, we deal with an electrode-free reflective liquid crystal cell, where image formation is achieved by coating one of the substrates with optically active azo dye thin film. To describe reflective characteristics of the cell, we develop a simulation model based on a continuum theory with the successive solution of the Maxwell equations for light propagating in anisotropic liquid crystal media. Computation of reflective characteristics was carried out by using the 8 × 8 transfer matrix method, which is the solution of Maxwell equations. By changing boundary conditions, we have obtained different reflectance coefficients (from ~0.03 to 0.43), and the corresponding chromatic colours were generated. Our results were obtained by using the modelling and optimisation system MOUSE-LCD. [ABSTRACT FROM AUTHOR]

Highlights • scanner path utilized as a manipulatable variable in paper machine cross-directional control. • faster response to load disturbances. • estimation of process noise and basis weight estimate uncertainty based on web-wide transmittance measurement. • adaptive model between transmittance and basis weight. ABSTRACT The cross-directional (CD) basis weight control on paper machines is improved by optimizing the path of the scanning measurement. The optimal path results from an LQG problem and depends on how the uncertainty of the present estimate of the basis weight and the intensity of process noise vary in CD. These factors are assessed by how accurately the CD basis weight estimate predicts the measured optical transmittance with a linear adaptive model on synchronized basis weight and transmittance data. Simulations on optimized scanner path in disturbance scenarios are presented, and the practical implementation of scanner control is discussed. [ABSTRACT FROM AUTHOR]

Usage of cellulosic nanofibers, starch-nanocellulose, and polyacrylamidenanocellulose hybrid systems were investigated for the replacement of imported long bleached kraft fibers in the production of durable papers. In this study, imported softwood kraft pulp was added to cotton pulp at four levels. Nanofibrillated cellulose (NFC) prepared from chemimechanical pulp was added to cotton pulp at a 5% level with optional 1% cationic starch or 0.1% cationic polyacrylamide. Comparative tests were done without NFC at three levels of either cationic starch or cationic polyacrylamide. For each condition, 80 gm-2 handsheets were made, and the physical, mechanical, and optical properties of the paper were compared. The results showed that increases of NFC yielded higher surface smoothness, tensile strength, resistance to bursting, tearing energy, folding endurance, yellowness, and opacity. It also reduced brightness and porosity whether added singly or in combination with cationic starch or polyacrylamide. Increasing cationic starch also increased surface smoothness, tensile strength, resistance to bursting, and folding endurance, but paper opacity was reduced. The field emissionscanning electron microscopy results showed that increased NFC reduced porosity, the paper surface became smoother, and the pores were relatively filled. Finally, the combined treatment of 5% NFC and 1% cationic starch is introduced as a suitable combination. [ABSTRACT FROM AUTHOR]

• It is shown that the commented paper has severe errors. • The analysis of the diffraction pattern was made without success. • The chemical composition of the studied crystals is unknown. My comments concern the errors in the crystallographic part of the commented paper. Moreover, the true chemical composition of the studied sample is different than BaNaFeWO 6 as proposed by authors. Therefore, the subsequent data on other measurements may have no scientific value. [ABSTRACT FROM AUTHOR]

• It is shown that the commented paper has severe errors. • The analysis of the diffraction pattern was made without success. • The chemical composition of the studied crystals is unknown. My comments concern the errors in the crystallographic part of the commented paper. Moreover, the true chemical composition of the studied sample is different than BaNaFeWO 6 as proposed by authors. Therefore, the subsequent data on other measurements may have no scientific value. [ABSTRACT FROM AUTHOR]

An ultrafast and efficient strategy is developed to produce homogeneous GQDs through instantaneous photothermal gasification and recrystallization, revealing the promising potential for large-scale production. [Display omitted] Graphene quantum dots (GQDs) are attractive fluorescent nanoparticles that have wide applicability, are inexpensive, nontoxic, photostable, water-dispersible, biocompatible and environmental-friendly. Various strategies for the synthesis of GQDs have been reported. However, simple and efficient methods of producing GQDs with control over the size of the GQDs, and hence their optical properties, are sorely needed. Herein, an ultra-fast and efficient laser writing technique is presented as a means to produce GQDs with homogeneous size from graphene produced by the instantaneous photothermal gasification and recrystallization mechanism. Controlling the laser scan speed and output power, the yield of GQDs can reach to be about 31.458 mg/s, which shows promising potential for large-scale production. The entire process eliminates the need for chemical solvents or any other reagents. Notably, the prepared laser writing produced GQDs (LWP-GQDs) exhibit blue fluorescence under UV irradiation of 365 nm and the Commission Internationale de L'Eclairage (CIE) chromaticity coordinates is measured at (0.1721, 0.123). Overall, this method exhibits superior advantages over the complex procedures and low yields required by other existing methods, and thus has great potential for the commercial applications. [ABSTRACT FROM AUTHOR]

Nitrogen doped fluorescent carbon dots (N-CDs) with high quantum yield (QY=87. 76%) were synthesized by solvothermal method using diphenylamino-4-benzaldehyde and o-phenylenediamine as raw materials and ethanol as solvent. The optical properties of N-CDs in organic solvents and aqueous solutions were investigated, indicating that N-CDs have good solvent dependence and chemical stability. The addition of water constructed a hydrogen bonding grid in N-CDs, thereby achieving a redshift in emission wavelength, and the N-CDs solution changes from blue to yellow. Furthermore, based on the reversible color change from blue to yellow of N-CDs fluorescent test strips, a portable air humidity visualization detection test strip was prepared. In addition, N-CDs can also be used for fluorescent ink, writing paper, and fluorescent flexible films, which expanding their applications in information transmission, advanced anti-counterfeiting encryption, and solid-state fluorescence. [ABSTRACT FROM AUTHOR]

The use of mineral fillers in the paper industry has attracted much attention due to its low cost and ability to improve optical properties and printability. Besides the filler characteristics, paper properties, such as bulk, tensile, and opacity, are greatly affected by filler distribution in the z-direction. Therefore, optimization of filler distribution is an effective way to maximize the value of fillers. In this work, a filler distribution factor (Fc) was proposed to quantitatively describe the concentrated degree of filler distribution in the z-direction. The reduction in Fc resulted in an increase in paper bulk, porosity, and opacity, due to the generation of more interfaces between fibers and fillers. When filler particles were concentrated in one layer (Fc = 1), the tensile strength of the filled paper increased between 26 to 40% in comparison to the paper with various Fc values. For a given Fc, better tensile and opacity properties were achieved by increasing filler concentration on the surface layer of paper. [ABSTRACT FROM AUTHOR]

In this paper, we study theoretically the electron and spectral properties of Ge 1 − x Sn x systems, including alloys, cubic- and spherical quantum dots. The single-particle electron and hole states are calculated within the s p 3 d 5 s ∗ tight-binding approach and used in further modeling of the optical properties. We systematically study the interplay of Sn-driven indirect–direct bandgap transition and the quantum confinement effect in systems of reduced dimensionality. We demonstrate the regime of sizes and compositions, where the ground state in Ge 1 − x Sn x quantum dots is optically active. Finally, we calculate absorbance spectra in experimentally relevant colloidal quantum dots and demonstrate satisfactory agreement with experimental data. [ABSTRACT FROM AUTHOR]

The development of sensitive, cheap, and portable methods for detecting nitroaromatics explosives has a profound significance and value for public health and environmental protection. For this purpose, a new D-π-A barbituric acid derivative CB-CYH with aggregation-induced emission (AIE) behavior was synthesized, which can interact with picric acid through photoinduced electron transfer (PET). Scanning electron microscopy (SEM) and dynamic light scattering (DLS) indicate that the enhanced emission of the compounds is related to the formation of nano-aggregates. It is well known that an important source of mechanochromic fluorescence (MCF) characteristic materials is the compound with AIE characteristics. The chemosensing test paper prepared by aggregated nanoparticles based on AIE properties is often subjected to external friction or squeeze during transportation or storage, resulting in changes of their optical properties, and destruction of test paper followed. Therefore, the development of compounds with AIE properties and stable optical properties in the presence of external stimuli is particularly important for chemosensing test paper. Molecular dynamics simulation (MDS) shows that the presence of hydrophobic cycloalkyl group in CB-CYH, which caused the molecules to be closely interspersed with each other; hence, it is difficult to change the microstructure and stacking mode of molecules by external stimulation simultaneously; the optical properties are not changed by external stimuli. Therefore, the test paper based on the AIE effect of CB-CYH was developed as chemosensing test paper for the detection of nitroaromatics. [ABSTRACT FROM AUTHOR]

Paper money passes through various environments during its life span, causing its physical, chemical, and optical properties to change. More than 90% of paper money worldwide is composed of natural cotton fiber. The present study examined the properties of paper money made of bleached softwood kraft fibers or its blends with cotton fibers, where nanofibrilled cellulose was employed as a strengthening agent. Nano-cellulose was added at 4 levels: 0, 0.3, 0.6, and 0.9%. Handsheets with a basis weight of 90 g·m-1 were made by mixing the pulp furnish with nano-cellulose in the identified percentages, and the physical and mechanical properties of the handsheets were tested. By increasing the amount of nano-cellulose up to 0.9% in cotton pulp, the tensile strength, bursting resistance, tear resistance, and resistance to folding endurance were increased by 33, 33.5, 6.6, and 63.2%, respectively, compared with the control sample. The addition of nano-cellulose up to 0.9% in cotton pulp increased the surface smoothness by up to 13.5% compared with the control sample, and porosity and water absorbance decreased by 16.6 and 4%, respectively, in comparison with the control sample. By increasing nano-cellulose up to 0.9% in cotton pulp, the opacity, brightness, and whiteness were decreased by 0.1, 1, and 4%, respectively. The SEM results indicated that the increased nano-cellulose percentage led to decreased porosity. [ABSTRACT FROM AUTHOR]

Predicting paper properties based on a limited number of measured variables can be an important tool for the industry. Mathematical models were developed to predict mechanical and optical properties from the corresponding paper density for some softwood papers using support vector machine regression with the Radial Basis Function Kernel. A dataset of different properties of paper handsheets produced from pulps of pine (Pinus pinaster and P. sylvestris) and cypress species (Cupressus lusitanica, C. sempervirens, and C. arizonica) beaten at 1000, 4000, and 7000 revolutions was used. The results show that it is possible to obtain good models (with high coefficient of determination) with two variables: the numerical variable density and the categorical variable species. [ABSTRACT FROM AUTHOR]

Bacterial cellulose is a biological macromolecule synthesized by bacteria of high purity and crystallinity. Bacterial cellulose nanofibers (BCNF) have been produced by soft homogenization and added to a recycled pulp to improve its quality. The benefits of BCNF on mechanical, physical and optical paper properties have been quantified and the retention mechanism of the BCNF in the paper network has been proposed. The use of BC to improve paper strength is usually limited by the decrease of tear index. The novelty of this work is that these two effects are decoupled by the addition of BCNF of low fibrillation (35.2%). In this way, some BCNF clusters are produced together with the individual nanofibers. Thus, with the addition of 3% BCNF, tensile and tear indexes as well as strain at break were improved by 11.1, 7.6, and 66.8%, respectively. Furthermore, the clusters were retained in the fiber network not only by hydrogen bonding, but also by physical retention within the gaps. Therefore, the addition of BCNF not only increases the mechanical properties of paper but also makes the handsheets more flexible and facilitates filler retention. [ABSTRACT FROM AUTHOR]

A phenomenological kinetic equation is obtained for the change in color difference and brightness of banknote paper during aging. A solution is obtained for the kinetic equation. The coefficients of the kinetic function are determined from experimental data. Kinetic functions are constructed for three samples of the banknote paper. By analysis of the coefficients of the kinetic function it is possible to compare the paper according to its resistance towards the aging process. [ABSTRACT FROM AUTHOR]

The effect of changing the sequence of refining and enzymatic treatment on the properties of deinked pulp from mixed office waste paper (MOW) was investigated. The sequences included refining before and after enzymatic treatment. Refining was applied for 700 and 1500 revolutions, and the consistency of pulps during enzymatic treatment was 5, 8, and 13%. Enzymatic treatment was applied for 20, 40, and 60 min. After each of the sequences, the deinking stage was the same. When refining was applied after the enzymatic treatment, the freeness of pulp was greater than that of the pulp on which refining was conducted before the enzymatic treatment, at a constant refining speed. Better strength properties were produced when refining was carried out before the enzymatic treatment. Also, the results of testing the optical properties of deinked pulp showed that brightness and ERIC improved when refining was carried out before the enzymatic treatment. [ABSTRACT FROM AUTHOR]

Inorganic fillers are usually used in papermaking industry to reduce production costs and enhance paper optical properties. As an attempt to improve fillers application in papermaking, carboxymethyl cellulose (CMC) and poly aluminum chloride (PAC) were used to encapsulate precipitated calcium carbonate (PCC) filler and modify its surfaces. In the first step, the optimum conditions for filler treatment (i.e. pH, CMC and PAC contents) were obtained. Through the second step, different amounts of CMCencapsulated PCC were added to fiber suspension and some hand-sheets were made. Then, the effect of modified filler addition in different levels of 20, 25, and 35% on mechanical and optical properties of paper was investigated. The PAC dosage was found to be a critical factor for effective encapsulation of PCC fillers by carboxymethyl cellulose. When the dosages of CMC and PAC were 4% and 0.8% (based on the dry weight of PCC), respectively, filler modification caused to improve significantly the retention by more than twice. Strength properties of the hand-sheets fabricated with the CMC/PAC-modified PCC were also found to be significantly better than those obtained with the unmodified PCC at similar levels of filler content. In addition, the brightness and opacity of the filled papers at 30% addition of CMC-modified fillers were strikingly enhanced to 88,45 and 77%, respectively. SEM observations of the filled papers also demonstrated that CMC-encapsulated filler particles were clustered and retained efficiently onto the fiber network. The present method for modification of PCC may provide an alternative approach to increase the filler amount in the paper structure by alleviating filler drawbacks. [ABSTRACT FROM AUTHOR]

• Numerical model for solution of heat diffusion equation. • Thermographic investigation in optically semi-transparent materials. • Non-destructive detection of graphic features buried in cultural heritage artefacts. • Selective configurations for optical and thermal properties investigation in paper. In this paper, infrared thermography is applied to the quantitative characterization of optically semi-transparent media by using a newly introduced mathematical model. The method is specifically aimed to the detection and evaluations in graphic features buried beneath the surface of some particular kind of cultural heritage artefacts, such as books and documents. A numerical approach based on the finite element method, is proposed for solving the model equations. The computed thermographic signal depends on different inspected material physical properties, which have been selectively evaluated by comparing the theoretical results with the experimental ones in specifically designed test samples. Thereafter, the model is applied to the analysis of the results obtained in the case of graphic elements buried within samples constituted by the same previously characterized materials. [ABSTRACT FROM AUTHOR]

Managing food contamination from bacteria has been an ongoing issue in the public health and industrial fields. Enzymatic substrates possessing optical properties, e.g. fluorescence or color manifestation, are widely exploited in pathogenic/non-pathogenic bacteria culture methods. Recently, various chromogenic substrates have been utilized in the development of point-of-care diagnostic tools. Herein, four types of chromogenic substrates were exploited to develop paper-based sensors for major foodborne pathogens. We designed a compact sized three-dimensional paper device with a simple user interface. By inserting functional layers in the middle of multilayers, pre-lysis and pH regulation steps were excluded and the analysis time was subsequently reduced, while only one sample droplet was needed for the whole analysis process. After the enzymatic reactions had proceeded, target-specific colors appeared. When it was combined with enrichment, 101 cfu mL−1 of pathogens were successfully detected in 4–8 hours, while those in milk samples were readily sensed in 12 hours. The proposed bacteria sensor exhibited great advantages of low cost, portability and simple operation, while showing a respectable limit-of-detection as low as 101 cfu mL−1 and below. Significantly, we emphasize that it takes fewer steps than existing methods and provides a reduced analysis time owing to the layer functionalization. [ABSTRACT FROM AUTHOR]

This study explored the fascinating field of high-performance nanoscale metallic multilayer composites, focusing on their magnetic, optical, and radiation tolerance properties, as well as their thermal and electrical properties. In general, nanoscale metallic multilayer composites have a wide range of outstanding properties, which differ greatly from those observed in monolithic films. Their exceptional properties are primarily due to the large number of interfaces and nanoscale layer thicknesses. Through a comprehensive review of existing literature and experimental data, this paper highlights the remarkable performance enhancements achieved by the precise control of layer thicknesses and interfaces in these composites. Furthermore, it will discuss the underlying mechanisms responsible for their exceptional properties and provide insights into future research directions in this rapidly evolving field. Many studies have investigated these materials, focusing on their magnetic, mechanical, optical, or radiation-tolerance properties. This paper summarizes the findings in each area, including a description of the general attributes, the adopted synthesis methods, and the most common characterization techniques used. The paper also covers related experimental data, as well as existing and promising applications. The paper also covers other phenomena of interest, such as thermal stability studies, self-propagating reactions, and the progression from nanomultilayers to amorphous and/or crystalline alloys. Finally, the paper discusses challenges and future perspectives relating to nanomaterials. Overall, this paper is a valuable resource for researchers and engineers interested in harnessing the full potential of nanoscale metallic multilayer composites for advanced technological applications. [ABSTRACT FROM AUTHOR]

Context and results : In this paper, the crystal structure, electronic, optical, and mechanical properties of SrVO3 have been systematically studied by first-principles calculation. The results show that the calculated lattice parameters are in good agreement with the experimental values of X-ray diffraction. The density of states is described in detail in this paper. By analyzing the crystal structure and electronic properties of SrVO3, the magnetic properties of SrVO3 are obtained from the one unpaired electrons of V and the exchange interaction between two V ions. At the same time, a detailed analysis of the optical properties of SrVO3 was conducted, and it was found that it is transparent in the visible light range. Finally, the mechanical properties of SrVO3 are calculated, which can provide some references for future research. Computational method: In this paper, a first-principles method based on density functional theory (DFT) is reported for PBE-GGA analysis using the plane wave-pseudo potential method in a quantum concentrate packet, U value of 7 eV to V-d and a U value of 2 eV to O-p, Grimme correction by DFT-D method. The k points in the Brillouin region are set to 4 × 4 × 4. The energy convergence criterion for self-consistent field calculation is set at 5.0 × 10−6 eV/atom, and the cutoff energy is 1170 eV. In this paper, the force acting on each atom is not more than 0.01 eV/Å, the maximum stress is not more than 0.02GPa, and the maximum atomic displacement is 5 × 10−4 Å. [ABSTRACT FROM AUTHOR]

Reflective electrochromic (EC) technology is expected to e‐paper display field, and integrating optical reflective electrolyte as the optical reflective layer is a common strategy for constructing reflective EC devices. Compositing inorganic particles and electrolytes is one of the simplest and most efficient composite methods, but these composite electrolytes usually cannot perform well together in terms of both optical and electrochemical properties. Herein, the TiO2 nanoparticles are added to the ethyl viologen‐based ionogel (T‐EVG, one typical kind of EC/electrolyte) to have the highest visible light reflectivity and the best electrochemical performance compared with SiO2, Al2O3, and ZnO nanoparticles, which is attributed to the electro‐induced self‐reduction TiO2 produced in T‐EVG during EC cycling. Meanwhile, the corresponding EC devices can display red, green, and blue, and have high optical contrast (CIE Lab: ΔE>38), fast switching spend (<4 s, the fastest is 5 Hz), ultra‐low power density (<4.0 mW cm−2), and excellent cycling stability (>85% retained after 10 000 cycles). Finally, a simple 3×3 pixelated EC display array is prepared, and single‐ and multi‐point (including diagonal points) multi‐color display effects are realized through active‐matrix driving and high‐frequency refresh, demonstrating its application value in the high‐performance e‐paper display. [ABSTRACT FROM AUTHOR]

The goal of this study was to analyze the effects of cellulose fibers loading by precipitation in-situ of calcium carbonate over the properties of printing paper obtained from mixtures of the softwood and hardwood fibers. The effects of fibers with in-situ loading were analyzed comparatively with conventional paper loading respectively, by adding precipitated calcium carbonate into fiber stock. The effectiveness of the methods was evaluated by various analyses and investigations: calcium carbonate content, Scanning electron microscope (SEM) images, X-ray diffraction, optical and mechanical properties of the paper sheets. The evaluation of the effects on paper properties led to the conclusion that, at the same filler content, the in-situ loading method gives higher opacity and brightness than conventional methods. The utilization of cellulose fibers with in-situ loading as additive, shown as a modification of the ratio between fibers with in-situ loading and fibers without loading, regardless of whether they are softwood or hardwood fibers, allowed us to optimize printing paper properties, especially regarding the relationship between optical and strength properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Mechanism of humidity sensing for a CdS nanoparticle coated paper based humidity sensor. Highlights • Mechanisms of humidity sensing on a film of CdS nanoparticles. • Adsorption of water molecules with the flow of humid gas varied conductance of film. • Adsorption of water on sensor was correlated with band bending of the film. • Logarithmic dependence of flowrate of humid gas and concentration of adsorbed water molecules was found. Abstract A combined experimental and computational study is presented to identify the salient features of the adsorption of water molecules from a humid gas on the surface of a film of cadmium sulfide nanoparticles (CdSNPs). It is well known that, apart from showing exquisite optical and electrical properties, CdSNPs are also capable of adsorbing humidity from the gas or vapors. In the present study, we explore the variation in the electrical conductivity of a film of CdSNPs with the variation in the flowrate of a humid gas, which can lead to the development of a humidity or a flowrate sensor. The computational study shows that the increase in the concentration of adsorbed molecules with the enhancement in the flowrate of the humid gas can lead to a variation in the electrical conductance of the CdSNP film. The adsorption of water molecules on the sensor is correlated with the band bending of the CdSNP film owing to the ionization of the adsorbed molecules on the sensor surface. The electrical conductance of the sensor is found to vary in the range of 55–95% when the flowrate of the humid gas is varied from ∼200 to 600 L/min, at a relative humidity of ∼97%. A logarithmic dependence of the flowrate of the humid gas with the concentration of the water molecules adsorbed on the film surface is found to explain the experimental observations. [ABSTRACT FROM AUTHOR]

Microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) isolated from cotton linters were evaluated as a strength additive in unbleached kraft paper and compared with semi-empirical and mechanistic models. The z-directional tensile strength was enhanced due to NFC and MFC. The tensile energy absorption (TEA) derived via integrating the z-directional stress-strain curve was 29.165 J/m2, 120.658 J/m2, and 187.768 J/m2 for the control, MFC, and NFC, respectively. Burst factor significantly increased from 11 to 14 for 10% MFC, while no increase was observed in NFC. From TEA predictions by semi-empirical models, a modified Page equation, Shear-lag, and a negative trend was found due to increased relative bonded area (RBA) with the addition of MFC/NFC. The mechanistic model used six mechanisms involved in binding the fibers and predicted the increased trend of TEA. The increased TEA due to NFC contributed to z-directional tensile strength, but not to the tensile indices and tear factor. This was ascribed to the large size difference of NFC with base pulp fibers and a higher RBA. [ABSTRACT FROM AUTHOR]

The processes of banknote deterioration in circulation and the factors causing this wear have been analyzed to determine the main factors in the process of banknote deterioration in real life circulation and to ascertain which of these factors could be simulated in the process of simulated circulation. The factors that should be taken into consideration during simulated circulation are systematic mechanical and chemical influences on a banknote. The developed Circulation Simulator Method was used to evaluate Ukrainian hryvnia banknotes to obtain artificially deteriorated banknote samples whose optical properties, weight change, air permeability, bursting strength, and stiffness were within the range of corresponding parameter changes for bank notes in actual circulation. The designed method consisted of multiple mechanical damages to tested banknotes by means of centrifugally rotating them within a closed container containing a wearing agent in the presence of a soiling mixture, which imitates the typical composition of soil in banknote circulation within Eastern Europe. The proposed method can be used to determine the durability of materials and to develop manufacturing processes for banknote production. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites are currently in high demand for developing various types of flexible electronic devices.In the progress of polymer nanocomposite materials, herein, tin oxide (SnO2) nanoparticles and PVA:CA/SnO2 conductive polymer nanocomposite papers were synthesized by the sol–gel method as flexible polymer electrodes. Different molar concentrations of SnO2 were used as a conductive agents in nanocomposites, and citric acid was used to improve the mechanical properties of PVA/SnO2 hydrogel nanocomposite. The nanocomposites were characterized by X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM), transmission electron microscopy (TEM) analysis, and UV–Vis spectroscopy. The XRD results showed that at an annealing temperature of T = 500 °C, the structure of SnO2 nanoparticles is completely crystalline and corresponds to the tetragonal structure. Also, the intensity of diffraction peaks indicates the increase in the size of nanocrystals and a strengthening of the crystal order. TEM imaging of SnO2 nanoparticles showed that the size of nanoparticles after annealing at T = 500 °C is in the range of 5–25 nm. The results of UV–Vis spectroscopy also showed that the optical transmission by injecting SnO2 nanoparticles into the polymer substrate reduces the optical transparency and adding citric acid to the polymer substrate increases the transparency of PVA:CA/SnO2 nanocomposites compared to PVA/SnO2 polymer. Also, the energy gap from PVA/SnO2 and PVA:CA/SnO2 nanocomposite papers showed that by increasing the concentration of SnO2 nanoparticles, the energy gap decreases, and the energy gap was estimated in the range of 3.15–4.04 eV. [ABSTRACT FROM AUTHOR]

Cellulose nanofibres (CNFs) can improve the quality of cardboard packaging. This work evaluates the ability of CNFs to impart barrier properties to commercial paper used in packaging. Three CNFs were tested: mechanical (m-CNFs), by TEMPO mediated oxidation (T-CNFs) and carboxymethylated (c-CNFs). Two metering systems (wound rod and blade micrometer) were used to apply one, five and 10 layers of CNFs suspensions, and two drying methods (hot air jet and contact with a hot polished surface in a speed dryer) were evaluated. The quality of the CNFs coated papers was measured by structural (thickness, roughness and air permeance) and optical properties (gloss) and visual appearance. c-CNFs coatings obtained the lowest air permeance values, from 0.1 to 0.01 μm/Pa·s depending on the number of coating layers, and were below those of commercial starch. T-CNFs also reduced air permeance at low weights, reaching 1.1 μm/Pa·s with one layer and 0.1 when five layers were applied. Five layers of m-CNFs were needed for good results. SEM images showed good coverage at low coat weight in c-CNFs and T-CNFs, whereas m-CNFs was unable to cover the base paper. With increased layers of m-CNFs, an adequate film was formed. c-CNFs had the highest fibrillation degree and acid group content, and was the CNFs coating with most potential as a coating for paper. [Display omitted] • Mechanical and chemical nanocelluloses applied with different coating technologies • Evaluation of air barrier, structural and visual properties of coated papers • First study with coated nanocelluloses assessed at a specific roughness level • Best results of the multilayer methodology when five layers were coated • Nanocellulose coated papers were compared with a commercial cationic starch. [ABSTRACT FROM AUTHOR]