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Statement of problem Quick response (QR) codes are a fast and efficient technology for linking and accessing identifying information, and their use has been proposed in forensics. The heat resistance and esthetics of denture marking methods (DMMs) have been recommended by the American Dental Association (ADA), but studies on these aspects of printed QR codes are lacking. Purpose The purpose of this study was to determine the optimal printed material with QR codes for implementation as a DMM adjusted to the recommendations of the ADA. Material and methods The behavior of 4 types of paper, bond paper, fiberglass filter paper, ultralong hydroxyapatite nanowire paper, and polyolefin and silica paper with printed QR codes was analyzed. They were exposed to temperatures between 100 °C and 1000 °C in a heat muffle for 1 hour. Each specimen was subjected to both a morphological and a thermogravimetric analysis (TGA) and scanned by using 3 different smartphones. Results The scans were positive for bond paper (33.3%), fiberglass fiber paper (50%), ultralong hydroxyapatite nanowire paper (100%), and polyolefin and silica paper (70.4%). The TGA revealed continuous decomposition curves (average 16.5 minutes at 624 °C). Conclusions Printed QR codes on ultralong hydroxyapatite nanowire paper appear to be suitable as information reservoirs, even surviving incineration, and may be implemented as a DMM conforming to the ADA recommendations.

Million tons of cellulosic paper have been used for insulating coils in oil-filled electrical power transformers, thereby assuring the electricity supply for our societies. The high working temperatures in transformers constantly degrade paper insulators throughout their service life of up to 40 years. We approached the structural changes in oil-immersed cellulosic paper samples upon thermal stress in a study that compared unbleached softwood Kraft paper used as insulator paper with pure cotton cellulose paper. The model experiments used a thermal treatment in transformer oil at 170 °C for up to 14 days. The samples were characterized by means of 13C CP/MAS NMR spectroscopy, mainly based on deconvolution of the C4 resonance. An automated, fast, and reproducible C4 resonance deconvolution employing the “Peak Analyzer” tool of OriginPro 2020 (OriginLab Corporation, USA) was developed and used to exploit 13C CP/MAS NMR spectroscopy for the characterization of thermally stressed paper samples. Our results show that thermally induced structural changes depend heavily on the composition of paper, that hornification and coalescence of fibrils take place, and that the allomorph composition of cellulose crystallites is altered under the given conditions. Graphical abstract

Poly ( p-phenylene benzoisoxazole; PBO) paper is a potential raw material for use in honeycomb sandwich composites in the aerospace industry, which are able to sustain high temperatures exceeding 300°C. This work presents a wet-forming method of making PBO paper, consisting of PBO chopped fibers. The paper was impregnated with phenolic resin to simulate honeycomb wall material. The structure and mechanical and dynamic mechanical properties of the raw and impregnated paper were characterized. The performance of PBO paper was tested against p-aramid paper. The comparative results showed the tensile strength of PBO raw paper was 2.17 kN/m, which was slightly worse than p-aramid raw paper: 2.66 kN/m. After impregnation, the tensile strength of the PBO paper was 13.93 kN/m due to the increase in the number of bonding points—better than p-aramid paper: 7.99 kN/m. The tearing resistance value for PBO raw paper versus p-aramid raw paper was 3252 mN against 845 mN. The morphology of the torn samples in the impregnated paper revealed higher levels of PBO fiber pullout than p-aramid fiber, therefore the tearing resistance value was 6000 mN for PBO impregnated paper, which was again superior to p-aramid impregnated paper: 675 mN. The PBO paper also showed higher storage modulus than p-aramid paper after impregnation. Experimental studies showed that PBO paper could be used in load-bearing structures and in honeycomb components where high resistance to deformation and thermal stability is necessary.

Water absorption is a key property in several tissue paper materials and can be a differentiating factor in terms of consumer choice. The converting modifications applied in the tissue industry can improved absorbency properties. For this purpose, the main goal of the present work is to study the influence of “deco” and “micro” embossing on water absorption capacity, Klemm capillary rise, and liquid spreading kinetics in tissue papers. An industrial never-dried bleached eucalyptus kraft pulp, a creped industrial base tissue paper, and a disintegrated fibrous suspension obtained from the same industrial paper were used to produce structures with and without “deco” and “micro” embossing patterns. The results indicate that the “micro” embossing process promoted bulky and porous structures, enhancing water absorption capacity and Klemm capillary rise properties, while the “dec” embossing pattern decreased water absorption capacity properties. The creping process also increased the water absorption capacity but decreased Klemm capillary rise properties along with the fiber mixtures. Regarding the liquid spreading kinetics, both embossing patterns decreased this property in uncreped isotropic structures, contrary to creped anisotropic structures. The eucalyptus and softwood fibers mixture improved the spreading kinetics compared to the creping process. The performance of structures with and without embossing allowed to quantify the liquid retention properties, combining ISO experimental methods and an optical system that records the liquid interaction with fibrous structures. In conclusion, this laboratory embossing method can be used as an alternative method to optimize converting operations and the final tissue paper characterization, on a laboratory scale.

The blend (wax M) of crude by-product polyolefin wax (wax K) and a fractionated commercial paraffin wax (wax J) was suggested to replace the wax J as a coating agent for wax-coated papers. The rheological properties of waxes J, K, and M were examined and compared. The correlation between viscosity and shear rate applied on these waxes maintained at 90 oC and 130 oC was identified. In particular, this paper, for the first time, presented non-Newtonian shear thinning behavior of not only wax K but also its blend of wax M in terms of their viscosity affected by shear rate at an operating temperature below their melting temperature of higher-melting-temperature DSC endothermic peaks (HMTEPs). They showed non-Newtonian behavior, so-called shear thinning behavior, at 90 oC in the light of characteristics of both suspension systems and polymer systems. In addition, the profiles of viscosity at 130 oC of all the waxes versus the shear rate exhibited Newtonian fluid behavior. Wax J also showed the behavior of a dilatant fluid. Then, the physical properties including water vapor transmission rates (WVTR), surface roughness, and coated weights, of thin papers coated with waxes J (WJP), K (WKP), and M (WMP) were evaluated, characterized, and compared. As a result, WMP had an equivalent value to that of WJP or the lowest value among wax-coated papers in terms of WVTR. The surface roughness and the barrier property of WVTR were minimized and enhanced, respectively, by blending waxes J and K. The additional physical properties, including dynamic contact angles, surface tension, wet and dry tensile strength, optical examination of the wax-coated fiber structure, and antimicrobial properties of the wax-coated papers, were evaluated. The excellent antimicrobial properties of clinoptilolite added to wax J or wax M appeared.

The pursuit for sustainability in the papermaking industry calls for the elimination or reduction of synthetic additives and the exploration of renewable and biodegradable alternatives. Cellulose nanofibrils (CNFs), due to their inherent morphological and biochemical properties, are an excellent alternative to synthetic additives. These properties enable CNFs to improve the mechanical, functional, and barrier properties of different types of paper. The nanosize diameter, micrometre length, semicrystalline structure, high strength, and modulus of CNFs have a direct influence on the mechanical properties of paper, such as tensile index, burst index, Scott index, breaking length, tear index, Z-strength, E-modulus, strain at break, and tensile stiffness. This review details the role played by CNFs as an additive to improve strength properties of paper and the factors affecting the improvement in paper quality when CNFs are added as additives. The paper also includes techno-economic aspects of the process and identifies areas that need further research.

In this paper, the mechanical properties of nano-silica modified insulating paper under the combined action of mechanical vibration and temperature conditions are studied. Unmodified and nano-silica modified cellulose insulating paper with 2 wt% and 4 wt% were prepared, respectively, and a series of mechanical-thermal synergy experiments were carried out. With the same mechanical stress and temperature, and with the same aging duration of 144 h (6d), the tensile strength of modified insulating paper with 4 wt% nano-silica, increased 0.99 kN/m and 0.55 kN/m, respectively, compared with those of the unmodified and the 2 wt% nano-silica modified insulating paper. The experiments indicate that the nano-silica modification can effectively improve the mechanical properties of insulating paper. In this work, the modified mechanism of nano-silica is analyzed from the interface effect of modified polymer and the quantum effect of the modified polymer interface two aspects. It is shown that the interface formed in the modified insulating paper can transfer the mechanical stress acted on the insulating paper and prevent the cracks formed in the aging process of the test sample from further expansion, while the quantum effect discretizes the electron energy level, which can restrict the motion of the molecular chain segment to some extent. The conclusion can be used for reference to improve the performance of insulating paper.

Graphene paper with good mechanical strength, flexibility, and high conductivity is an emerging functional material for wide applications, but its feasible and scalable preparation remains a challenge. Herein, a high strength, flexible, and conductive graphene/polypropylene (PP) fiber paper was prepared by a traditional papermaking process. In the composite paper, graphene nanosheets were well stabilized on the PP fibers forming a stable three-dimensional conductive interleaved network. Chitosan was found able to build a polar active interface on PP fibers and graphene nanosheets, which can not only promote PP fiber dispersion in water yielding a uniform pulp, but also favor the retention of graphene in the composite paper. As a result, the composite paper presents high strength (15.32 MPa), good conductivity (11,995 S/m), shielding effectiveness (31.1 dB), water resistance, fungi-proof, and thermal conductivity (10.17 W m−1 k−1) properties. This work demonstrates the feasibility of large-scale preparation of graphene composite paper with commercial synthetic fibers through a traditional papermaking process, and expands the potential industrial application of graphene materials. Graphene/chitosan co-aggregates were absorbed on the surface of graphene/chitosan/PP fiber under the electrostatic interaction of CPAM to form graphene/PP fiber.

To explore the reinforcement effects of different reinforcement methods, kraft paper was used as reinforcement material, and shear tests were carried out in sand to study the reinforcement effects of kraft paper perpendicular and parallel to the shear plane. The test results show that the two reinforcement methods can effectively improve the strength of sand and the orthogonal reinforcement form is more superior. The existence of reinforced materials greatly improves the cohesion of sand, but does not significantly improve the internal friction angle. The width of reinforcement material has little effect on the reinforcement effect and shows different variation laws under different reinforcement forms.

Mechanical properties are crucial in assessing the paper quality. Deformation and strength properties of paper are determined by the strength and stiffness of the interfiber and intermolecular hydrogen bonds. The contribution ratio of interfiber and intermolecular hydrogen bonds to the strength of paper can be changed by adjusting the degree of its anisotropy. The article presents the results on a study of the deformation properties of laboratory anisotropic paper samples from kraft bleached softwood pulp with a beating degree of 30 °SR. The samples had basic weight of 90 g/m2 and the degree of stiffness anisotropy TSIMD/CD of 1.75–4.08. They were made by using Techpap SAS automatic dynamic handsheet former (Grenoble, France), with varying forming parameters – diameter of the nozzle, motion speed of the forming wire, and injecting speed of pulp. Deformation properties were determined by tensile test and processing of the stress-strain dependence (σ−ε). The outcomes have shown that, an increase of the fiber orientation degree in paper structure by changing the forming parameters caused a change in the nature of the paper deformation under tension. Increasing the fiber orientation degree in the structure of paper made it possible to increase the strength by 55 %, tensile stiffness by 63 % in the machine direction, while reducing the extensibility by 10 %. In the cross direction, it was possible to decrease tensile stiffness by 33 %, strength by 55 %, and increase the extensibility by 5 %. Anisotropy of tensile strength was 1.73–6.00. The greatest effect was obtained for the elasticity modulus in the pre-failure zone E2 (2.8–38.6). It means that, fiber orientation had a key importance when large deformations in the samples took place. The established quantitative regularities allowed optimizing the values of the deformation and strength properties of paper, and their ratio in the machine direction and cross direction due to the variation of the forming parameters. For citation: Rech D., Potasheva A.N., Kazakov Ya.V. Regulating the Deformation Properties of Paper by Varying the Degree of Its Anisotropy. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 174–184. DOI: 10.37482/0536-1036-2021-5-174-184

In order to study the feasibility of kraft paper as watercolor paper, the wetting properties, mechanical properties and friction properties of kraft paper and watercolor paper were compared before and after aging. The aging test was carried out on kraft paper and the watercolor paper by aging chamber, the wetting properties of distilled water and three watercolor solutions before and after aging of kraft paper and watercolor paper were compared, tensile tear test of paper on the tensile testing machine, the fracture changes of paper were analyzed by scanning electron microscope, the friction tester performs the paper friction test. The results show that both kinds of paper are amorphous, watercolor paper was showed hydrophobicity before and after the aging, the contact angle was maintained at about 119,09° ± 5° in four different solutions, unaged kraft paper exhibited hydrophilicity, the aged kraft paper showed hydrophobicity with a contact angle of 92,52° ± 1°，the aged kraft paper shows better performance in both tensile and tearing aspects and tensile strength is 20 MPa higher than watercolor paper, the surface roughness of kraft paper is higher than watercolor paper. The experiment is helpful for the market to consider whether the cheaper kraft paper replaces the more expensive watercolor paper in some aspects and provides some scientific reference value for future research.

Free-standing reduced graphene oxide (rGO) papers were prepared by chemical reduction, thermal reduction and combined chemical-thermal reduction, respectively. Four-point probe and nanoindentation experiments were conducted to investigate the electrical and mechanical properties of rGO papers. The rGO paper prepared by soaking in L-ascorbic acid and thermal annealing in argon at 1000 °C (labeled rGO-AsA-T) showed superior electrical and mechanical properties when compared with rGO papers prepared merely by chemical reduction or thermal reduction. The as-prepared rGO-AsA-T paper exhibited an electrical conductivity of 5.7 × 104 S/m, showing an increase of 90% compared to that in the thermally annealed rGO paper and nearly 40 times that of rGO paper reduced by L-ascorbic acid. It was also found that the rGO-AsA-T paper had the lowest elastic modulus of 288 MPa, showing enhanced flexibility. The nearly free voids in rGO-AsA-T paper proved by scanning electron microscopy (SEM) were due to the capillary action in chemical reduction and were significant in improving the electrical conductivity and flexibility of the paper. The rGO-AsA-T paper with high conductivity and flexibility has a promising application in flexible electronics.

Paper mulch has the advantages of simple process, low production cost and strong degradability, but it is still a great challenge to prepare paper mulch with excellent water resistance and light transmittance. In this paper, through a simple physical brushing method, Zinc oxide (ZnO) solution and silica (SiO2) solution were brushed on the surface of paper mulch film respectively, and ZnO/SiO2 composite superhydrophobic paper mulch film (CSPMF) with micro-nano rough structure was constructed. The microstructure of original paper mulch film (OPMF) and ZnO/SiO2 CSPMF was studied by scanning electron microscope (SEM), and the superhydrophobic surface elements were analyzed by energy dispersive spectrometer (EDS). The contact angle (CA) and rolling angle (RA) of two kinds of sample surfaces are measured by contact angle meter. The static CA and RA of ZnO/SiO2 CSPMF were 160 ± 0.4° and 3 ± 0.3°, respectively. The self-cleaning behavior of soil simulated dust environment was tested on the surface of OPMF and ZnO/SiO2 CSPMF respectively. The horizontal bounce performance and tilt bounce performance of the superhydrophobic surface were tested by high-speed camera. In addition, frost experiments and delayed icing experiments were carried out. The results show that ZnO/SiO2 CSPMF has good self-cleaning performance, bouncing performance and delayed icing performance.

Sandwich-structured nanocomposites have the potential to improve the mechanical and electrical properties of materials simultaneously. Nanofibrillated cellulose (NFC) modified paper sheet (denominated as N) and softwood paper sheet (denominated as P) are used to prepare insulating paper. Different kinds of insulating paper with the structures of PPP, NNN, NPN and PNP are prepared. Tensile strength, DC conductivity, dielectric response, space charge and breakdown strength are measured. The activation energies of prepared materials are calculated through DC conductivity at 30, 50, 70, and 90 °C. The mechanism for sandwich structure regulating the mechanical and breakdown properties of insulating paper is discussed. Oil impregnated N/P/N paper has a remarkable improvement on tensile strength, conductivity, and DC breakdown strength, which provides a promising scheme to obtain the insulating paper with outstanding tensile and breakdown strength.

Commercial Chinese ink was employed to disperse pristine vapor-grown carbon nanofibers (VGCNFs) in aqueous suspensions via horizontal ball milling. The obtained suspension was used to fabricate conductive paper-based composites through filtration-deposition onto filter paper. It was found that the carbon black particles from the Chinese ink helped separate VGCNFs and acted as connection points between the VGCNFs, while the glue reinforced the conduction network. Thus, the VGCNF-ink/paper ternary composite showed sufficiently low sheet resistance. With merely 2.5 mg·cm−2 VGCNFs, the sheet resistance could be reduced to 4.5 Ω·sq−1. As a proof of concept, these paper-based composites were directly used as electrodes of solid-state symmetric electronic double-layer capacitors (EDLCs) and the substrate for the electrodeposition of MnO2 to achieve higher electrochemical performances. The EDLCs fabricated with 2.5 mg·cm−2 VGCNFs showed a specific capacitance of 224 mF·cm−2 at a current density of 1 mA·cm−2, which was retained by 86.4% after 10,000 charge-discharge cycles. Moreover, thanks to the high electrical conductivity and the porous structure, the MnO2 decorated paper-based composites exhibited dramatically enhanced specific capacitance. It is believed that our finding offers an idea to directly utilize commercial Chinese ink for the fabrication of electrode materials.

The in-situ synthesis of calcium silicate in the fiber can not only meet the requirements for high loading of paper, but also make up and improve the reduction of paper performance caused by filling. In this investigation, the effects of pulp type, beating degree, fiber ratio, reaction time, rotational speed, dosage of lime milk and dispersant on calcium silicate loading and paper properties were investigated. The results showed that when the beating degree was 40 °SR, the ratio of softwood and hardwood pulp was 1:1, the reaction time was 60 min, the rotation speed was 600 r·min−1, the dosage of lime milk was 1.33 times of the theoretical amount, and the dosage of cationic polyacrylamide was 0.3 % (absolutely dry pulp), the ash content of hand-made sheet was 41.2 %, and the loading amount of calcium silicate was 26.3 %. Under this condition, the comprehensive performance of paper was the best.

The research aims to evaluate the efficiency of some consolidation materials for tracing paper; hydroxypropyl cellulose (Klucel-E), zinc oxide nanoparticles and nanocellulose. The consolidated materials were used independently, and as hybrid mixtures to improve their properties. The prepared nanomaterials were examined with an Atomic Force Microscope (AFM), and the materials used to consolidate the tracing paper samples after artificial aging were evaluated. Evaluation methods included investigation of the surface morphology by Scanning Electron Microscope (SEM), measurement of mechanical properties (tensile strength and elongation), and detection of chemical changes of the treated samples before and after thermal ageing at 80°C and 65% relative humidity by Fourier transform infrared spectroscopy (FTIR) analysis. Based on the results of the examinations, consolidation by the hybrid mixture consisting of hydroxylpropyl cellulose and nanocellulose proved to be successful; giving the best results when this hybrid mixture was applied on tracing paper samples. This mixture was distinguished by its ability to spread easily inside the paper, giving greater strength to the binding, without forming a film on the surface of the paper and causing stiffness or opacity to treated tracing paper. Therefore, this hybrid mixture was used to consolidate an archaeological tracing map at the Egyptian Geographical Society dating back to (1807 AD).

A new coating method was developed, based on cellulose regenerated from an N-methylmorpholine N-oxide (NMMO) solution applied to paper. In particular, the purpose of this study was to compare the effectiveness of the “deep coating” method using cellulose regenerated from NMMO solution and the classic pulp refining process as methods to improve paper mechanical properties and overall quality. The “deep coating” name comes from the fact that the coating process is combined with subsequent heating of the coating before its final solidification. As a result of this operation, deep penetration of the cellulosic solution into the paper structure occurs. This increases the contact surface of the solution with the cellulosic fibers, which increases the strength properties of the paper structure. It was found that the cellulosic coating increased the apparent density of the paper, the tensile strength, the elongation, the resistance to bursting, and the double fold number. However, the coating also decreased the air permeability and the tear resistance of the paper samples. Despite some technological difficulties, this method could be an attractive solution in the case of a need for additional functionalization of a paper structure.

Excellent mechanical and electrical properties of graphene-based paper-like materials are essential for applications in flexible conductors, energy-storage devices, etc. The graphene oxide (GO) supernatant separated by centrifugation and ultrasonication has been used to prepare graphene oxide paper and reduced graphene oxide paper (rGOP) with high strength and conductivity. However, this method has cumbersome steps and low supernatant concentration, which greatly increases time and energy consumption, and is not suitable for rapid batch preparation of high-strength and high-thickness rGOP. Herein, a high-speed mechanical shearing method has been used to efficiently exfoliate graphite oxide suspension into high-concentration GO slurry with large lateral size, and rGOP has been further prepared by blade coating and HI acid chemical reduction. Compared with the product prepared by ultrasonic exfoliation method, the average area of GO sheets obtained via the mechanical shear exfoliation method can reach around 16.31 μm2. As a result, the mechanical properties and conductivity of the prepared rGOP have been increased by 30% and 23.5%, respectively, with the tensile strength and electrical conductivity of 478.2 MPa and 208.4 S/cm being obtained. The developed method is of great significance for the large-scale production and emerging applications of lightweight and high-performance rGOP.

Due to great advantages, such as simple operation, high porosity, and good fiber continuity, the working principle and research progress of electrospinning technology was studied and polyvinyl alcohol (PVOH) nanofibers were prepared via this process. Air filter paper was used as the receiving substrate to prepare electrospun nano air filter paper (NAFP). The PVOH concentration, static voltage, and receiving distance, were tested to explore the influence of spinning parameters on the filtration performance. Further, the microfiber morphology of the electrospun NAFP was observed. The performance of filter paper, including air permeability, pore size, initial resistance, filtration efficiency, and dust retention, were tested. The results showed that the electrospun NAFP had better filtration performance compared to the air filter paper, and simultaneously they had lower initial resistance and higher precision filtration efficiency. The nanofiber influenced the surface of the air filter paper, as it sharply reduced the pore size. When the spinning condition was 10%, 21 kV, and 15 cm, the pore size decreased approximately 0.6 times of the original, which meant the electrospun NAFP could capture particles ≥ 0.2 μm in size. Finally, after three repeated uses, the good filtration performance was maintained.

Dual-purpose coated paper, which enables in-line inkjet printing with web offset, can be used for both offset and inkjet prints. This product has potential to meet the ever-increasing demand for printing individualized information on commercial printing materials. In this work, commercial samples were printed in the two presses. It was deduced that low permeability correlates with large color gamut volume. The correlation would be useful to design coating formulations for good printability. Also, we examined the packing of coating layers to identify a coating formulation that provides good printing quality in both offset and inkjet printing. Many combinations of pigments were tested, and the effects of particle shape on viscosity and packing were examined. For all coating colors, pigment mixtures with a weight ratio of 3:1 gave the highest packing density. The mixture of GCC 90 and delaminated clay with a weight ratio of 3:1 was the best selection studied for dual-purpose coated paper. Among commercial paper samples, a web offset coated paper showed the best overall performance, indicating that coating formulations with minimal blistering are suitable for dual-purpose coated paper.

10 Pág. Instituto de Ciencias Forestales (ICIFOR), The high humidity produced by the ripening of fruit and vegetables during refrigerated storage and transport leads to a noticeable loss of strength of corrugated board packaging. Increasing use of recycled fibres in the manufacture of corrugated board further reduces box compression strength. Adding virgin fibres to the furnish composition of liner paper could solve this problem. Various proportions of unbleached virgin eucalyptus and pine fibres were added to a recycled furnish used to manufacture liner paper for corrugated board. Laboratory sheets of each fibre blend were characterised by tensile, bursting and compressive strength. The change in the strength properties and moisture content of the sheets during refrigerated storage at 6°C and high relative humidity (90% RH) was also studied. The results showed that paper strength improved with the proportion of virgin fibres added. Pine fibres yielded higher increments than eucalyptus fibres in tensile and burst indices, whereas both fibres improved compression strength at a similar rate. After 4 h of exposure at refrigerated storage, the paper strength properties decreased considerably, in particular compression strength, which showed a loss of about 70% compared to the reference value. The percentage of strength lost compared to the value in standard conditions was influenced only by exposure time at low temperature and high RH. However, an increase in the amount of pine fibres added enhanced the remaining tensile and burst indices., The authors wish to thank the Madrid Regional Government for funding through project RETO PROSOST P2013-MAE2907 and theIPT support foundation (FIPT) for subsidising the training project of the researcher Renato Fioritti in Spain (INIA-CIFOR). They are also grateful to Purificación Pereira for her contribution to the experimental work

A new type of polydimethylsiloxane-based paper transparentizing agent was prepared via a combined method. The performance of the transparentizing agent was investigated systematically by adding and dipping, with use of the surface sizing device of a paper machine. Optimum performance was found at 30% concentration of the transparentizing agent and 30 to 45 °C of dipping temperature. Under the optimal conditions, the transparentizing t agent achieved a rapid penetration in the base paper and filled in the pores of the paper, to be further effectively adsorbed and retained on the fiber surface. The transparency of test paper reached as high as 76±0.97 %, which was 37±1.4% higher than that of the control. However, the addition of transparentizing agent reduced the mechanical strength of paper slightly. The as-prepared transparentizing agent was found to exhibit excellent application stability and biodegradability when applied in the paper machine，When used as plastic film, the transparent paper would lose its strength completely after eight weeks. The resulting transparent paper can be used to develop paper-based film and other related plant based transparent/ translucent paper, which has great potential in replacing plastic products and eliminating white pollution.

In the packaging sector of the printing industry, different coating applications are tried and investigated in order to increase the surface appearance and performance characteristics of paper and cardboard. The printability, water and ink absorption capacity, frictional resistance, light sensitivity of the visual graphical design that are going to be printed on the packaging papers are some of them. In this study, different types of cardboards that are used as a packaging material were chosen and coated with nanocrystalline cellulose (NCC)/PVA at different rates (%). In order to determine effective and economical usage conditions, the coating solutions, at three different concentrations as 3 wt.%, 5 wt. %, 7 wt.%, were prepared. The coating was applied on the test papers, which were at the same weights (350 g/m2) and had different surface properties as matte glossy, bright glossy, American Bristol. NCC/PVA existence on the coated paper surface was confirmed with Fourier Transform Infrared Spectroscopy (ATR-FTIR). The impact of the coating, which was prepared at different concentrations, on the packaging materials was studied with respect to thickness, stiffness, water absorbability, contact angle and surface tension.

It remains a challenge to prepare special engineering paper with excellent mechanical properties, high temperature resistance and chemical resistance. The emergence of high-performance fiber provides support for the technical progress of special engineering paper. Herein, a novel method to obtain a novel self-reinforced poly (ether ether ketone) (PEEK) composite paper (SR-DI-PEEK/paper) by vacuum filtration, impregnation and hot pressing. Specially, PEEK fibers were used as the skeleton fiber and a small amount of aramid pulp was added as the decanted fiber. By optimizing the process of SR-DI-PEEK/paper preparation, the best mechanical properties of SR-DI-PEEK/paper was presented. Compared with the composite paper prepared with Phenolic solution (PF-PEEK/paper) and Polyimide solution (PI-PEEK/paper), the mechanical properties of SR-DI-PEEK/paper was significantly improved. In particular, when the concentration of impregnation was 3 wt%, the tensile index of SR-DI-PEEK/paper reached 51.10 N m g−1 (tensile strength 47.16 kN m−1), which is 16.48 times than that of the un-impregnated PEEK/paper (2.86 kN m−1). SR-DI-PEEK/paper also exhibited excellent chemical resistance among acid, alkali, and polar solvents, while the tensile index maintained 96.3% after 40 wt% H2SO4 treatment. Besides, SR-DI-PEEK/paper showed superior thermal performance, while the temperatures corresponding to the weight loss of 5% were 574 °C.

This paper aimed to modify the ignitability of the bagasse paper by using talc powder, 1,3-di-aniline-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane, and nanocellulose crystal. The formation of cellulose nanocrystals (CNCs) was detected using transmission electron microscopy (TEM), X-ray diffraction (XRD). Thermal analysis as thermal gravimetric analysis (TGA) of the specimens recorded the improvement of the highest % of ash residue at 750 °C compared to the untreated one. The shape of the flame spread was studied. The ignition properties were studied for the untreated and treated specimens by limiting oxygen index (LOI) and flame chamber (UL/94), which recorded enhancing compared to the untreated specimen. This improvement was recorded either by measuring the mechanical properties (tensile strength, burst strength, elongation, and elasticity) of the specimens. The current article showed that the treated specimen was recorded the highest values compared to the untreated one in all physical, mechanical, and ignition properties, so these treatment paper sheets may be used as fire-retardant packaging materials.

Gelatine sizing was used extensively for western papermaking before the nineteenth century and this technique is still applied nowadays for restoration purposes. Despite its wide use, the relationships between gelatine types, the strength of the size and its distribution inside the paper sheet are still unclear. Different concentrations of three gelatines of various origins and types (A/B) were used to size model papers. The gelatine uptake, the strength of the size and the presence of gelatine at the papers surface were investigated by using a water drop test method and ATR-FTIR spectroscopy. At a given concentration, similar uptakes were found for all gelatines but great variations were observed in terms of size strength and of gelatine ability to cover the surface of paper sheets. In addition, Scanning transmission X-ray microscopy was performed on paper fibres cross sections to map the distribution of the organic compounds (both cellulosic and proteinaceous) on a nanometer scale. This showed that gelatine coats but does not penetrate the fibres. It can be inferred that the different size strengths observed between the tested gelatines are mainly due to different ways of filling holes between fibres inside the paper mat, some gelatines being more prone to go inside the sheet than others which remain mostly distributed near the surface.

There is a relative lack of research on the development of creepage discharge in aged oil-paper insulation subjected to AC-DC combined voltage in converter transformers. In this study, based on the physical and chemical properties of oil-paper, we propose a sphere-plate electrode model to study the creepage discharge parameters and characteristic spectra of aged oil-paper subjected to AC-DC combined voltage. The results show that the creepage discharge inception voltage of aged oil-paper is related to the AC voltage component of the AC-DC combined voltage. However, when the DC voltage component is 60 kV, the flashover phenomenon was found to occur in one of the severely aged samples before the AC voltage was applied. Despite being subjected to the same DC voltage, the flashover phenomenon did not occur in three other samples aged to different degrees. Large-amplitude discharges were found to appear earlier in the severely aged samples. At the same creepage discharge stage, as the aging time of the oil-paper increased, the number of large-amplitude discharges was found to rapidly increase, and the time interval between adjacent discharges was found to gradually decrease. At each stage of the creepage discharge, the small-amplitude discharge has a “hump” shaped distribution. The larger the DC voltage component, the shorter the endurance time of aged oil-paper, and the more severe the damage to the oil-paper. The DC voltage component was found to have an accelerating effect on the development of creepage discharge in aged oil-paper insulation.

Microfluidic paper-based analytical devices (μPADs) have been widely explored for point-of-care testing due to their simplicity, low cost, and portability. μPADs with multiple-step reactions usually require precise flow control, especially flow-delay. This paper reports the numerical, mathematical, and experimental studies of flow delay through wax valves surrounded by PDMS walls on paper microfluidics. The predried surfactant in the sample zone diffuses into the liquid sample which can therefore flow through the wax valves. The delay time is automatically regulated by the diffusion of the surfactant after sample loading. The numerical study suggested that both the elevated contact angle and the reduced porosity and pore size in the wax printed region could effectively prevent water but allow liquids with lower contact angles (e.g., surfactant solutions) to flow through. The PDMS walls fabricated using a low-cost liquid dispenser effectively prevented the leakage of surfactant solutions. By controlling the quantity, diffusion distance, and type of the surfactant predried on the chip, the system successfully achieved a delay time ranging from 1.6 to 20 minutes. A mathematical model involving the above parameters was developed based on Fick's second law to predict the delay time. Finally, the flow-delay systems were applied in sequential mixing and distance-based detection of either glucose or alcohol. Linear ranges of 1-100 mg dL-1 and 1-40 mg dL-1 were achieved for glucose and alcohol, respectively. The lower limit detection (LOD) of glucose and alcohol was 1 mg dL-1. The LOD of glucose was only 1/11 of that detected using μPADs without flow control, indicating the advantage of controlling fluid flow. The systematic findings in this study provide critical guidelines for the development and applications of wax valves in automatic flow delay for point-of-care testing. This journal is

This work investigates the influence of blending waste paper and cement at fixed proportion with varying proportions of chicken feather fiber (CFF) and wood saw dust (WSD) as reinforcements. Samples produced were tested for flexural properties and water absorption potentials. The outcome showed that with increasing CFF content and reducing WSD content, water absorption reduced while flexural strength, modulus of ruptures (MOR) and modulus of elasticity (MOE) increases. MOR and MOE were at peaked when the ratio of CFF to WSD was 3:2 while flexural strength reached it crescendo at 4:1 of CFF to WSD. It was noticed that higher CCF content from 3 to 5 wt% gave better results in most of the investigated properties compared to WSD. Therefore, it was concluded that low quantity of WSD is needed to form a synergy with CFF in order to achieve optimum results. Well dispersed CFF-WSD phase in waste paper-cement based composites was observed to be responsible for the enhancement in the investigated properties.

The paper corrugation tube is an innovative kind of energy absorbing structure and shock absorber which can play an important role on the cushioning energy absorption for airdrop equipments and transportation packaging. The deformation characteristics and failure modes of the regular triangle, quadrangle, pentagon and hexagon paper corrugation tubes were comparatively studied by a series of axial static compression experiments, the cushioning energy absorption was evaluated by the seven characteristic parameters (e.g. initial peak force, mean crush force, total energy absorption, specific energy absorption, crush force efficiency, unit area energy absorption and stroke efficiency), and the influences of tube direction, cross-sectional shape, tube length and compression rate on failure modes and cushioning energy absorption were analyzed and compared. These researches showed that the tubes along X direction only have the accordion deformation mode, yet the tubes along Y direction have four deformation modes including steady state progressive buckling, Euler buckling, angular tear and transverse shear. For the paper corrugation tubes along Y direction, the cross-sectional shape has obvious influence on the cushioning energy absorption of structures, and the specific energy absorption and unit area energy absorption of regular triangle and pentagon tubes are better than those of the tubes with regular quadrilateral and hexagonal cross-section at compression rates of 12 and 48mm/min. The tube length of 150 mm or compression rate of 72 mm/min would cause the increase of contribution proportion of non-ideal deformation mode and the decrease of cushioning properties. The paper corrugation tubes along X direction have more stable and controllable deformation mode, yet the paper corrugation tubes along Y direction have better cushioning energy absorption.

[EN] Recent trends in waste management have initiated interest in recycled materials for sound absorption applications. The present paper studies the possibility of paper sludge to be recycled as material for sound absorption applications. Paper sludge (PS) is the water treatment waste, produced during paper production. Two different methods were studied to produce paper sludge and slaked lime composite acoustic panels for sound absorption applications at low and mid-frequencies. The sound absorption coefficient of paper sludge composite panels is measured in an impedance tube using the two-microphone method. The samples produced with different methods showed different behaviours of sound absorption. The primary method to produce showed acoustic asymmetry in the vertical direction of the samples, and it was considerably fragile as well. An improved method to produce PS composite panels was proposed in this paper. Using this method, homogenous and robust acoustic panels were obtained., The authors would like to kindly thank the technician Javier Zaragoza Dolz and Dr. Olga Kizinievi for their fruitful suggestions on this study. This research was financially supported by the Ministry of Science and Innovation and the European Union FEDER through Project PID2019-109175GB-C22

Aim of the present work was to deepen the knowledge on the effects of funori on cellulose fibers with particular attention paid to their consolidation. Compared to canvas, paper samples (untreated or artificially aged) show different fiber packaging and liquid-absorbing properties. Herein, we conducted observations of cellulose fibers by scanning electron microscopy (SEM) in order to evaluate the seaweed extraction method employed in this work, as well the consolidation action had on the fibers through multiple additions of the prepared solutions. Surface homogeneity and fiber stiffness observed by us increased over time and the fibers, initially frayed and disordered, were eventually incorporated into the purified funori after several solution additions accompanied also by a progressive occlusion of the pores. The achieved consolidation effect was confirmed by means of mechanical tests. Moreover, the method herein developed was slightly modified in view of the application of the funori solution to a cultural asset of historical and botanical interest, still scarcely studied. Electronic microscopy allowed us to evaluate the consolidation and gluing effect obtained through subsequent funori applications.

This paper focused on the studying of adsorption properties of Fe3O4-waste paper activated carbon composites for the removal of methylene blue dyes from water. The various parameters were carried out for the adsorption test of the composites, namely; contact time, adsorbent dose, initial MB concentration, pH solution, and temperature. The adsorption of isotherm, thermodynamics and kinetic was used to determine the characteristics of methylene blue adsorption onto the prepared adsorbent. The result indicates that the optimum adsorption capacity has occurred at pH = 6 in water solution. The adsorption capacity increase as the temperature increase until at 315K (45oC). The Langmuir isotherm is more appropriate to be applied as the adsorption model with the maximum adsorption capacity (qm) value of 101 and 93 mg/g for KA HCl-Fe3O4 and KA-Fe3O4 composites, respectively. The value of adsorption thermodynamic parameters was positive for ΔH, negative for ΔGo and positive for ΔSo, meaning the process adsorptions were endothermic, feasibility and spontaneity and randomness, respectively. The pseudo-second-order model was appropriate to predict the kinetic models for methylene blue adsorption onto the composites. The obtained adsorbent composites possess high adsorption efficiency and rapid magnetic separation. They were a promising for practical wastewater treatment for dyes removal from water.

This research is about the application of Bacterial nano cellulose (BNC) as a reinforcing material in the making of liner test paper. BNC was obtained from the fermentation of banana peel extract using Gluconacetobacter xylinum bacteria obtained from the making starter of nata de coco. The reason for using banana peel waste is because it’s available in large number all across Indonesia. BNC is mixed with secondary fiber as a raw material for making liner test paper. From the experimental handsheets results, strength properties and absorption properties were then tested. Variations in the composition of the use of BNC are 0% (blank), 5%, 10%, 15%, 20%, 25%, 30% of the handsheet dry weight. The BNC is also applicated on surface sizing as a substitute for the surface sizing agent. The results of this study indicate that BNC can be used as an alternative raw material on wet end and on surface sizing, because both applications can increase the strength properties of liner test paper, and can reduce the use of chemical additive. The highest increase in strength properties of liner test paper was obtained at the composition of nano cellulose 30% and using surface sizing. Ring crush index is 14.02 Nm / g, concora index is 12.73 Nm / g, bursting index is 3.78 KPa.m² / g, ply bonding is 388.57 J / m². The absorption properties of paper increases but it has a low prosity. The highest cobb size results are obtained at 30% BNC composition, which is 45.30 g / m2 without using surface sizing and 41.83 g / m² using surface sizing. The highest porosity value is obtained at 30% BNC composition, which is 158 s / 100cc using surface sizing. This research is expected to be a reference for further research in the field of BNC, as the alternative raw materials besides wood in paper making.

As a new type of energy harvesting device, the triboelectric nanogenerator (TENG) can convert mechanical energy into electrical energy effectively. Paper-based materials have gained considerable attention for use in flexible energy harvesting device applications because of their flexibility, environmental friendliness (i.e., they are biodegradable and renewable), and foldability. This work proposes a strategy to use cellulose fibers layer as a spacer of paper-based triboelectric nanogenerator (P-TENG). The P-TENG consists of a three-layer fiber material and a copper electrode. The three-layer fiber material comprises nylon, cellulose, and polypropylene, where the cellulose fiber layer contains millimeter-sized holes and is used as a spacer. Because of its attractive cuttability and flexibility properties, the P-TENG can be applied on a large scale in complex environments (e.g., sports fields, driving training fields) to detect signal changes caused by external pressure This type of device has great potential for application to the large-scale TENG field and may provide a new solution for TENG industrialization.

Insulation oil is an important dielectric in power devices, and many studies on mixed insulation oil have been conducted in recent years to improve the performance of insulation oils. To replace mineral oil directly, the authors previously developed a novel three-element mixed insulation oil successfully; the main parameters of which satisfy the IEC 60296-2012 standard for mineral oil. In the present study, the AC breakdown properties of insulation paper (pressboard) immersed by the new mixed oil and naphthenic mineral oil were compared. For both insulation oils, the increase in temperature cannot significantly reduce the breakdown strength of oil-immersed insulation paper (pressboard) at a low moisture content, and the increment of moisture content cannot reduce the breakdown voltage at a low temperature (25°C). The breakdown voltage decreases only when the two factors increase simultaneously. For the mixed and mineral oils, the AC breakdown voltage of oil-immersed paper (pressboard) with different thicknesses has significant difference. The mineral oil has a high breakdown voltage for the thin insulation paper, whereas the mixed oil has a high breakdown voltage when the thickness of the insulation paper (pressboard) exceeds 0.2 mm. This phenomenon is mainly caused by the breakdown field strength that varies with the increase of dielectric thickness and the different change trends of paper (pressboard) immersed with the mixed and the mineral oils. Moreover, the stack of thin multilayer insulation paper enables the mixed oil-immersed paper to have a higher breakdown strength than the mineral oil-immersed paper. For the AC breakdown voltage of oil-immersed pressboard with an oil-gap structure, the mixed oil is comprehensively superior to the mineral oil due to its larger relative permittivity.

With the increasing popularity of coated paper, it has been more widely used in printing, publishing, product packaging and commercial promotion. However, coated paper is prone to cracks after printing and folding which exposes to a white area which is referred to as fold cracking. This study investigated the coating properties of paper and coating factors influencing the fold cracking and aimed to provide guidance on how to reduce the problems of fold cracking. This paper mainly discusses the effects of pigment proportion, binder dosage, solids content, coating thickness and calendering pressure on fold cracking of coated paper after printing. Experiments show that when the coating consisted entirely of calcium carbonate, the degree of fold cracking is most serious. With the addition of kaolin, the fold cracking reduces. When the ratio of the number of parts of calcium carbonate to kaolin is 25/75, the area of fold cracking reaches its minimum value of 10.28 %. With increasing solids content of the coating, the fold cracking decreases initially and then increases. When the solids content is 55 %, the fold cracking reaches a minimum. Increased latex content reduced coating thickness and an increase in calendering pressure gradually reduce the degree of fold cracking.

Absorption capacity is a key feature of toilet tissue papers. Several parameters can affect their final absorption capacities, such as pulp composition, stock preparation, number of sheets, additives, bulk, grammage, and converting process parameters, such as the embossing operation. In this work, the absorption capacities of four different 2-ply industrial toilet tissue papers, as well as the respective base papers from the mother-reel was compared using the immersion method according to ISO 12625-8 (2010). Previously, these samples were characterized in terms of morphology, grammage, thickness, and bulk. It was concluded that the embossing operation noticeably increased the thickness and bulk of toilet tissue paper. Furthermore, it was also verified that among the various toilet tissue paper samples there was not a noticeable variation in the time of water absorption because the samples revealed similar morphology and porosity. However, it was found that the bulk increased more than 150%, resulting in an increase of water absorption capacity over 60%.

The oil-paper insulation in power transformer is under a complicated environment, and there is little research on the combined effects of winding vibration-generated mechanical stress and thermal stress on the aging of insulating paper. To investigate the effects of combined mechanical-thermal stress on the aging properties of insulating paper, this paper carried out accelerated aging test using the as-designed mechanical-thermal stress combined aging oven in the aging environment at the temperature of 130 °C, and the mechanical stress intensities of 1 MPa, 1.5 MPa and 2 MPa. Besides, the degree of polymerization (DP), tensile strength, infrared spectroscopy, and scanning electron microscope (SEM) tests were performed on the aging paper samples. The test results suggested that, the combined mechanical-thermal aging might be regarded as thermal aging with lower degradation activation energy; the DP and tensile strength of insulating paper markedly declined during the mechanical-thermal aging process. At the same time, mechanical stress promoted the destruction of glycosidic bond, intramolecular and intermolecular hydrogen bonds, and increased the insulating paper cracks and holes. Typically, the above factors accelerated the aging of insulating paper. Finally, an improved degradation rate equation for insulating paper with consideration of mechanical stress was put forward.

In this study, it is aimed to investigate the joining of filter paper, which we classify as oil, fuel and air filter by four different methods. It has been determined whether it meets the post-merger requirements or not. The oil, air and fuel filter papers are pleated using pleats, ultrasonic, metal clips, polyamide-based hot melt and heat after being pleated (folded) to form media. Post-merger macro studies were performed after combination. Media was transformed into final filter product than buble test, air permeability and pore size test were applied. In terms of bonding quality, respectively it can be said that the metal clips, hot glue, ultrasonic welding and heat bonding methods should be, but in considering both quality bonding and to make saving, then metal clips, ultrasonic welding, hot glue, and heat methods should be followed.

Coatings based on pigment and polymer binders are applied on paper surfaces to improve their surface, optical, and printing properties. Besides the coating composition, the structure and properties of the coated papers are influenced by the coating layer consolidation upon drying. In this study, the influence of drying conditions on the structure and properties of coating layers based on natural pigments (clay) and polymer binders (butadiene acrylonitrile latex) has been analyzed. Using a laboratory rod Mayer device, the coatings were applied as thin layer (about 15&ndash, 16 g/m2) on the paper surface and samples of coated paper were dried at 20 and 105 &deg, C temperatures. The optical, structural, and water absorption properties of the coating layer were evaluated by the measurement of gloss, opacity, void fraction, light scattering, and contact angle. The obtained results highlighted that both the drying temperature and latex content in the coating color have a synergic effect on the coated paper quality.

Background of this research is suspension packaging: fragile goods are attached to a panel of cardboard by wrapping it in stretch film. The panel is then appropriately folded, and the whole thing is placed in a cardboard box of corresponding dimensions. The primary objective of this study is to identify paper types that might be used in future as a more sustainable alternative for stretch wrap film. The experimental methods that are utilized are basically variants of mechanical pulling tests on paper samples. Sample preparation and sample size are adopted from international standards, but displacement control is adopted to detect relevant stretchability properties. Some kraft papers show a high ultimate tensile stress and a moderate stretchability, mainly permanent stretch as expected. Although the ultimate tensile stress of paper from recycled fibers is lower, some of these paper grades show a considerable higher stretchability including a higher elastic stretch. It is concluded that both kraft paper and paper grades from recycled fibers may be applicable as a wrapping material for suspension packaging. Further experimental research is needed to identify appropriate wrapping parameters for each paper type.

Cellulosic fibre composites from agriculture waste product bast fibre such Empty Fruit Bunch (EFB) oil palm has lower cost than normal softwood fibre and they are great alternative to be considered in insulation papermaking. For this purpose, EFB fibre, kenaf fibre and their blend were used to fabricate electrical presspaper samples through a laboratory papermaking process. The study of physical, mechanical and electrical properties such as cellulosic structure, tensile strength, AC voltage breakdown and lightning impulse breakdown strength were conducted according to the standard testing method of insulation IEC60243-1:2013. From this research, the physical structure, mechanical and electrical behaviour of mixed EFB and kenaf fibre insulation paper are comparable to Kraft paper and qualified the basic criterion to be an electrical insulation paper as required by IEC60641-2 standard. The purposes of this insulation paper produced is to be use in electrical transformers, therefore the same test should be repeated to the insulation paper that have undergone aging process at normal and accelerated operating temperatures.

Crease cracking of paperboard is important to control for the appearance and structural integrity of packages. Crease cracking is affected by creasing operation variables, as well as the physical properties of the paperboard. However, the effects of the physical properties are not clearly known. The objectives of this work were to identify the key material properties that affect crease cracking and to clarify the effects of fiber composition and starch. Laboratory sheets were produced from bleached and refined softwood and hardwood commercial pulp at grammage and thicknesses that match a typical paperboard. To mimic papermaking operations, surface starch was applied via a bench-top size press. The sheets were creased in the lab over a range of penetration depths, and reverse-side cracking was measured. The results showed that less reverse-side cracking was correlated with higher tensile post-peak energy, a lower bending stress, and a lower z-direction (ZD) stiffness. The tensile post-peak energy is a measure of the resistance to crack growth via fiber-bridging. The bending force and the ZD stiffness influence the forces that create cracks. It was observed that decreasing the ratio of hard-wood-to-softwood content and reducing the amount of starch would both decrease crease cracking.