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Abstract: Rice straw, rice husk and paper sludge are by-products and industrial waste, and are beneficial resources as raw biomass materials used for manufacturing value-added composite products. We investigated the effect on selected mechanical properties of adding rice straw, rice husk and paper sludge to wood composites to replace wood particles for manufacturing green pallets. Results showed that increasing the contents of rice straw and rice husk dramatically decreased the mechanical strength of the composites. This is because the wax and silicate coating of these materials obstructed the strong bonding with UF resin. When 10wt.% of wood particle was replaced with 10wt.% of paper sludge, the wood–paper sludge composites showed similar mechanical properties to those of wood particle. Wood particle can be replaced by 10wt.% of dried paper sludge in accordance with the minimum requirement recommended by standards in green pallet manufacturing. [Copyright &y& Elsevier]

Abstract: The damage to historical documents and books caused by the acidic character of paper is often manifested as a complete loss of their mechanical properties. Deacidification and restoration of archived paper objects require knowledge of the long-term behaviour of paper before and after repair actions. Our study was focused on the investigation of mechanical properties (tensile strength, stretch, tensile index, zero-span tensile strength, folding endurance) of original papers (one alkaline and three different acidic samples) exposed to five methods of dry-heat and moist-heat accelerated ageing. The degree of paper deterioration upon ageing was significantly influenced by the temperature and relative humidity, along with the intrinsic chemistry of the individual paper samples. The correlation matrix evaluated at a 95% confidence level for tensile strength, stretch, tensile index and zero-span showed linear correlations between these mechanical properties for all the paper samples. However, a linear dependence of folding endurance on zero-span tensile strength was found only for alkaline paper, which revealed the highest resistance to the accelerated ageing tests. In addition, the concentration of paramagnetic semiquinone species in the acidic lignin-containing paper samples was monitored by Electron paramagnetic resonance spectroscopy. [Copyright &y& Elsevier]

In this study, we investigated the compatibility of kraft paper and plastic wastes. Also, the physical and mechanical properties of the paper-plastic composite were determined. Pulverized kraft paper wastes and fine sachet water particles were weighed and mixed together using different mixing ratios (50% of paper & 50% of plastic (1:1), 33% of paper & 67% of plastic (1:2) and 25% of paper & 75% of plastic (1:3)). The method of composite production employed was extrusion method. The results of water absorption (WA) conducted on the paper-plastic composite material ranged between 0.03% - 0.16% and 0.03% - 0.20% for 2 and 24 hours respectively. The average values obtained for thickness swell (TS) ranged between 0.00% - 0.23% and 0.00% - 0.33% for 2 and 24 hours respectively. The average values obtained for tensile modulus ranged between 0.11GPa to 0.33GPa and the average values obtained for tensile strength ranged between 9.99MPa to 15.12MPa. The result obtained from this study shows that kraft paper wastes and water sachet wastes can be utilized as a composite material as they were compatible. In addition, 25% of paper & 75% of plastic waste (1:3) gives the best mixing ratio as indicated by the result with the most dimensionally stable and high strength properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Photoluminescent organic-inorganic spray formula was simply prepared. • Luminescent layer from organic adhesive binder mixed with lanthanide phosphor. • Glow-in-the-dark sheets demonstrated good mechanical, thermal and photostability. Abstract A simple formulation of an organic-inorganic composite for spray-coating was adopted toward photoluminescent paper sheets. The coating composite layer was composed of a synthetic organic adhesive binder mixed with an inorganic lanthanide-doped strontium aluminate pigment. Such pigment-binder formula was applied effectively onto paper sheets via spray-coating followed by thermal fixation. The applied transparent photoluminescent coated layer exhibited optimal excitation wavelength at 365 nm and emission band at 517 nm resulting in phosphorescence of the paper surface with a substantial development of green-yellow, bright white, turquoise, and off-white colors as indicated by CIE Lab color coordinates under ultraviolet irradiation. The mechanical, decay and lifetime properties of the composite photoluminescent coated layer were described. The standard techniques of morphological properties and elemental analysis were explored by scanning electron microscope (SEM), wavelength dispersive X-ray fluorescence (WDXRF), and energy dispersive X-ray spectroscopic analysis (EDX). The spray-coated paper sheets demonstrated good fastness to light and reversible phosphorescence without fatigue. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the impact of moisture on mechanical properties of insulation paper. According to the molecular modeling approach proposed by Theodorou, the amorphous cellulose models of insulation paper with different moisture contents were built up to calculate mechanical parameters and hydrogen bond networks. And relevant conclusions could be drawn through further analysis on these calculation results: water molecules can destroy hydrogen bond network between the neighboring cellulose molecules, which might be responsible for the significant decrease of Young's modulus and other mechanical parameters, while no appreciable effect of intramolecular hydrogen bonds on mechanical properties was detected. Thus tensile tests were also carried out to study the moisture influence on the Young's modulus, by which the result of the simulation was approved. [ABSTRACT FROM AUTHOR]

In this work, the physical and mechanical properties of bleached Eucalyptus pulp reinforced with nanofibrillated cellulose (NFC) are compared with those of traditional beaten pulp used in the making of writing/printing and offset printing papers. For this purpose, three different types of hardwood slurries were prepared: beaten pulps, unbeaten pulps reinforced with NFC, and slightly beaten pulps also reinforced with NFC. Physical and mechanical tests were performed on handsheets from these different slurries. The results showed that adding NFC to unbeaten pulps results in physical and mechanical properties similar to those in pulps used for printing/writing papers. Nevertheless, the best results were obtained in slurries previously beaten at slight conditions and subsequently reinforced with NFC. These results demonstrate that the addition of NFC allows a reduction in beating intensity without decreasing the desired mechanical properties for this specific purpose. [ABSTRACT FROM AUTHOR]

The main objective of this article is to investigate the potential of using pineapple leaves as non-wood materials for paper production. The chemical compositions of non-wood raw materials and the advantages and disadvantages of different pulping methods were reviewed. The advantages of solvent pulping process over other techniques in terms of scale production, water, energy and chemicals consumption, and pulp quality might be the driving forces of using this process in future production of pulps from pineapple leaves waste. Pineapple leaves are cellulosic, abundance agro-waste of pineapple industries with chemical composition of high cellulose contents. Good mechanical properties, renewable resource, and low cost fibers are the main factors that lead to high potential of pineapple leaves’ fibers to be used as alternative raw materials in paper industries. [ABSTRACT FROM AUTHOR]

Increasing demands and consumption of humankind make an increase in paper production, extending the accumulation of paper production wastes. Due to legislations pertaining to environmental pollution, it has become necessary to search for new areas where these wastes could be used. Some of the processes such as milling, purification, etc. of fillers in the production of building materials are expensive and their cost reduction is desirable; therefore, the objective of this research is to develop strong and multifunctional rigid polyurethane foam composites from bio‐based polyol that are filled with unpurified and high distribution in size, having paper waste sludge (PWS) particles, and to investigate the possibility to recycle them as filler in polyurethane composites. The rational amount of PWS particles is 5% by foam mass. PWS particles improve thermal conductivity, water vapor resistance, density, compressive strength, and modulus of elasticity as compared to neat polyurethane foam matrix. POLYM. COMPOS., 39:1852–1860, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: Sustainable recyclable paper and composite materials can be ideal choices for the construction of temporary structures for both exhibition spaces or for rapid-recovery shelters in emergency operations. The unique engineering and sustainable features of these structures need to be considered as an integral part of the design process from the conceptual phase. Engineering studies to analyze these structures should be as important as the overall artistic and architectural vision. This paper examines the use of environmentally creep-formed paper tubes for the design, construction, and exhibition of, “Portals to an Architecture”, a large temporary outdoor sculpture. [Copyright &y& Elsevier]

Abstract: In this study, the effects of décor paper grammage (weight per unit area) and adhesive type on the tearing index, breaking length, and mechanical (modulus of rupture and modulus of elasticity) of the decorative papers, and surface quality (abrasion resistance) properties of the overlaid particleboard panels were investigated. As the raw décor paperweight was increased, the properties of the paper, and mechanical properties and abrasion resistance of the overlaid panels were significantly improved. It appears that the décor paper grammage is the parameter, other than scratch resistance, which determines the end use of the particleboard surfaces with décor paper. While the adhesive type was found to influence the abrasion resistance, it did not statistically affect the mechanical properties of particleboard. In addition, melamine formaldehyde caused better abrasion resistance than did the urea formaldehyde and melamine urea formaldehyde. [Copyright &y& Elsevier]

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Abstract: In libraries and archives some of the items which, upon ageing, have acidified considerably since their production are so brittle that they cannot be handled without risking loss of material. In contrast to current deacidification processes, aminoalkylakoxysilanes (AAAS) improve the mechanical properties of paper. A simple AAAS, aminopropylmethyldiethoxysilane (AMDES) was used as a model to better understand previous observations made on these systems (hydrolysis, condensation and possible reactions with the organic substrate). The evaluation of the mechanical properties of papers that were treated with AMDES showed that there was no formation of a polymer network on the fibres’ surface. However, treated papers not only exhibited a high alkaline reserve, but also a significant increase in both their tensile breaking length and their folding endurance. Treatment of hygrothermally aged papers with AMDES provided improved folding endurance as well as a good resistance to ageing. Various oxidation treatments of the model papers using sodium hypochlorite led to the conclusion that the nature of the oxidised groups formed on cellulose did not seem to play a significant role in the strengthening mechanism but rather that this effect of AMDES mainly arose from hydrogen bonding between the two molecules. [ABSTRACT FROM AUTHOR]

In this work, a new strategy has been proposed where the waste paper, and their possible emissions are buried into the bricks to induce porosity and reduce the atmospheric pollution. The resulting porous bricks have been proved experimentally to have good durability, low density, low thermal conductivity and acceptable compressive strength comparing with the commonly used bricks. Different mixing percentages of a waste paper weight to wet clay have been tested, and a percentage of 1:10 seems to meet the usual standard for severe weather requirements. Many advantages have been achieved; enchantment the thermal insulation of the brick, increasing number of brick produced per ton of clay, reducing waste and their determinate effects, small reduction in the energy required to produce fired brick and producing homogeneous properties through the brick by properly initial mixing waste paper with wet clay. All these factors result in obtaining good brick characteristics with advantage of reducing waste. The procedures of measuring density, specific heat and thermal conductivity have been verified by obtaining experimental and theoretical values of thermal conductivity of the samples and good agreement has been observed. [ABSTRACT FROM AUTHOR]

Abstract: Recycle paper mills (RPM) contribute 30% of total pulp and paper mill segment in India. With 85% average efficiency of RPM, 5% waste (RPMW) is produced annually. RPMW which otherwise is land filled has been utilized to make construction bricks that serves a purpose of solid waste management, new revenue generation and earning carbon credits. RPMW-cement combination low carbon foot print bricks with varying composition of cement (0–20%wt) have been prepared and tested as per ASTM C 67-03a standards. RPMW has been characterized using X-ray fluorescence (XRF), thermogravimetric and differential thermal analysis (TG–DTA), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). TG–DTA confirms thermal stability till 280°C whereas SEM monographs show the pores and fibrous nature. From experimentation it is observed that waste-create bricks (WCB) prepared using RPMW-cement combination is light weight, shock absorbing and meets compressive strength requirements of ASTM C 67-03a. The brick making procedure being simple can be undertaken as rural entrepreneurship by unskilled labors of developing countries. [Copyright &y& Elsevier]

ABSTRACT Biopolymers and their composites were added during the formation of unbleached Kraft bagasse pulp paper sheets to improve the mechanical strength properties of the produced hand sheets. The biopolymers (cellulose, chitosan, and chitosan-cellulose composite) were either crosslinked or noncrosslinked and they were added in series of concentrations from 0.1% to 1.5%. The characterization of the samples using the Fourier transform infrared (IR) technique identified differences in the intensities of the characteristic IR absorption bands for chitosan, cellulose, and their composites, these differences are due to the various degrees of hydrogen bonding. The surface morphology of the biopolymers composites and the treated paper sheets were studied using SEM technique. Both the equilibrium moisture sorption and the diffusion coefficient of the paper sheets containing 1% additives were evaluated at regular time intervals. The long-term stability of the treated paper with biopolymers was verified by exposing the treated and the untreated sheets to hygrothermal ageing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40761. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanotube papers (CNT papers, also referred to as “buckypapers”) prepared from chemically functionalized single-walled CNTs are being investigated for their mechanical tensile properties. While the Young’s moduli are unaffected by the functionalization with diazonium salts of aniline or aromatic mono- and bis-amides tensile strengths of CNT papers are found to increase with a growing degree of functionalization, and more pronounced with a growing number of amide groups capable of hydrogen bonding. The importance of hydrogen bonding becomes evident after its inhibition through N-methylation of the amide groups, resulting in a distinct reduction of strength values. Scanning electron micrography indicates that a high degree of functionalization or a high number of amide group results in the formation of domains with aligned CNTs. [Copyright &y& Elsevier]

Enzymatic and chemical deinking not only significantly influence the optical and mechanical properties of deinked paper, but also influence the pulp properties and wastewater effluent generated. Both enzymatic and chemical deinking of mixed office wastepaper (MOW) and old newspaper (ONP) showed improvement in brightness (1.4-4.7 units), tensile index (1-14%), burst index (1.2-3.8%), freeness (1.9-2.9%), and residual ink removal (31.1-51.2%) but caused loss in opacity (0.1-2.6%) and tear index (0.1-9.6%). Chemical Oxygen Demand (COD) analysis indicated that effluent produced from enzymatic deinking were about 33.9% and 33.8% lower compared to chemical deinking of ONP and MOW, respectively. Meanwhile, Biological Oxygen Demand (BOD5) obtained from enzymatic deinking of MOW and ONP were 47.1% and 39.3% lower compared to the chemical deinking process, respectively. The results obtained in this work demonstrated that the quality of the pulp and paper obtained from enzymatic deinking process was better than that from the chemical deinking process. This suggests that enzymatic deinking has high potential as an alternative to the chemical method. [ABSTRACT FROM AUTHOR]

Dr. Ondrej Tyc is currently a postdoctoral researcher at IoP and his specialization is in the area of mechanical characterization of NiTi samples. The Coatings Editorial Board and Editorial Team would like to congratulate the winner of the Coatings 2023 Best Paper Award (Article). This paper is the outcome of a joint collaboration of two groups from the Institute of Physics (IoP) and the Institute of Plasma Physics (IPP), Czech Academy of Sciences in Prague, Czech Republic. [Extracted from the article]

Abstract: This paper presents results of an investigation into the potential use of recycling paper mill waste-water to replace mixing water in cement mortar systems for manufacturing concrete masonry products. The physical and mechanical properties of mortar containing various amounts of de-inking waste-water were consequently investigated. A key finding of this study was that replacing mortar mixing water with waste-water significantly improved workability and consistency of cement mortar mixtures. In particular the flow of mortar mixtures increased with increase of waste-water content up to 50% and then levelled off when waste-water content exceeded 50%. Correspondingly, the flow of mortar mix with 100% waste-water replacement at water/cement ratio of 0.50 was found to be equivalent to that of the reference mortar mix with 100% potable water at water/cement ratio of 0.60, indicating potential use of de-inking waste-water as water reducing admixture. The enhanced workability arising from waste-water addition however induced changes in mechanical properties of the hardened material. Compared to reference mortar, replacing 10% and 100% potable water respectively resulted in 19% and 60% reduction of compressive strength, with a corresponding 5% and 16% drop in bulk density, and up to 19% increase in drying shrinkage. Also, water absorption and volume of permeable voids increased with increasing waste-water dosage, albeit marginally. The benefits derived from rheology improvements compared to compromises in mechanical properties due to de-inking waste-water addition strongly indicate clear potential of using de-inking waste-water in production of lightweight cementitious building and masonry elements. [Copyright &y& Elsevier]

In this study, all‐cellulose composite materials are prepared through the dissolution and regeneration process using waste kraft papers as raw material in the sodium hydroxide/thiourea/urea solvent system. The degree of conversion is controlled by adjusting the microenvironment of the cellulose solvents, and the composite membrane is prepared by mixing the regenerated cellulose with the insoluble cellulose, which aims at adjusting the morphology and mechanical properties of the composite material. The shape of the regenerated cellulose after the dissolution and regeneration change from the original fiber into a sphere as shown by SEM images. The composite films show different phenomena, the insoluble part, and the matrix phase form a dense and strong network structure. The presence of this insoluble part increases the strength of the matrix phase and fundamentally changes the brittleness of the regenerated cellulose. This work provides a green and promising method to prepare high‐performance, environmentally friendly all‐cellulose composite materials. [ABSTRACT FROM AUTHOR]

The dynamic mechanical properties of coated offset paper before and after application of isopropyl alcohol and surfactant solutions have been investigated. The mechanical properties of the papers were studied with dynamical mechanical analysis in the tensile mode and the samples were submitted to a uniaxial loading in stress-strain measurements. An increase in the isopropyl alcohol concentration slightly reduced the mechanical strength, while the addition of surfactant clearly made the paper stiffer and weakened the paper strength. As the surface tensions of the liquids were adjusted to the same level, the changes in mechanical properties are ascribed to changes in water-induced wetting and subsequent changes in interfacial properties within the paper constituents. The storage and loss moduli of the paper after application of the surfactant solutions were twice those recorded after isopropyl alcohol treatment. The binder was not affected by the solutions, but there was significant debonding, disrupting the internal or surface structure in the base paper-coating layer interface, especially by surfactant solutions. [ABSTRACT FROM AUTHOR]

Various approaches have been exploited to copy nacreous structure into human‐made structural nanocomposites with similar structure and impressive mechanical performance. However, it is still facing a great challenge to produce large‐sized, strong, and tough, biopolymer‐based nanocomposite, especially for further scale‐up in practical application. Herein, a large‐sized and nacre‐inspired nanocomposite paper can be successfully prepared via a simple evaporation‐induced self‐assembly technique, based on assembling hybrid graphene oxide/sodium alginate (GO/SA) building blocks. Through optimizing the lamellar hybrid interfacial interactions derived from hydrogen‐bonding network, the nacre‐inspired nanocomposite achieves a unique integration of high strength (up to 350.3 MPa) and high toughness (22.4 ± 2.9 MJ m−3), are superior to natural nacre, almost all GO and SA‐related composites, and many engineering materials. The hydrogen bond‐property correlation, combined with a simple assembling technique, will provide a powerful path for the large‐scale production of lightweight, biopolymer‐based materials with excellent mechanical properties. [ABSTRACT FROM AUTHOR]

The paper analyses the effect of waste sludge from paper industry (paper sludge) on physical and mechanical properties of clay bricks, their microstructure and resistance to freezing and thawing. Paper sludge is not hazardous industrial waste mainly consisting of cellulose and calcite. Clay bodies were made from the mix containing from 5% to 20% of paper sludge and fired at 900 °C and 1000 °C temperatures. Open pore structure in the clay body is developed as a result of burnt cellulose fibres and calcite decarbonization. Physical and mechanical properties of clay bodies change depending on the content of added PS: shrinkage, density and compressive strength reduce, water absorption and effective porosity increase. It is recommended to add 5% of paper sludge to the clay body and fire it at 900 °C temperature, or alternatively add 5–15% of paper sludge and fire the clay body at 1000 °C temperature. In terms of resistance to freezing and thawing, such products are regarded as frost resistant in moderately aggressive environment, i.e. in structures protected from direct environmental effects. [ABSTRACT FROM AUTHOR]

This article presents a comparative study of two types of transformer solid insulation: standard Kraft and thermally upgraded Kraft papers. The paper samples were impregnated with two different fluids, namely a synthetic dielectric ester fluid, Midel 7131, and a synthesized mineral oil, Luminol Tri. The impregnated papers were submitted to, accelerated aging at 150°C, temperature higher than the temperatures found inside transformers, for extended periods. The results show that for the first hours of aging, the cellulose depolymerization was similar for all the four studied cases. At a specific point, the paper samples aged in the ester fluid exhibited a lower depolymerization exceeding the 8000 hours of aging without reaching the levelling-off degree of polymerization (LODP). A similar trend was observed through the decrease of mechanical properties of papers in the ester-based oil. However, the difference in performance of both fluids was amplified due to the temperature used; at lower temperatures the difference should be smaller. Additionally, a relationship between the degree of polymerization and the mechanical properties accessed by the tensile testing was obtained regardless of the type of paper or oil. The total acidity in the ester fluid was higher than in mineral oil. Methanol, a chemical marker that is closely linked to the rupture of 1,4-ß-glycosidic bonds of cellulose, showed a partial sensitivity to the cellulose aging in the ester fluid. Furan (C4H4O) content was monitored during the aging and its concentration was found to be sensitive to the depolymerization along with the decrease in the mechanical properties of cellulose papers regardless of the type of paper. More importantly, its concentration was found to be dependent on the type of oil. More investigations are needed to further confirm the importance of furan as an indirect indicator of the mechanical performance along with its correlation with the depolymerization of paper aged in ester fluids. [ABSTRACT FROM AUTHOR]

Two investigative stages are presented in this study, which aim to establish basic standards for the use of calcined paper sludge (CPS) in the stabilization of soils. The soils were stabilized with CPS and with mixtures of CPS and cement (C). The total percentage of binder was between 3 and 6% by weight. The blending ratios (by weight) of the CPS:C mixtures were 50∶50 and 25∶75. The first stage took place in the laboratory, and the second stage, in the field, involved in situ stabilization of 250 m of subgrade using dry-mix methods. The bearing capacity of the stabilized soils was determined in the laboratory. In the second stage, the densities of the subgrade were measured in the field following compaction and deflections at 7 days. Furthermore, the evolution of its unconfined compressive strength (UCS) was measured over 90 days. The results reveal optimal mechanical behavior of the stabilized soil at CPS:C ratios of approximately 25∶75. [ABSTRACT FROM AUTHOR]

Abstract: The texture of the C–S–H gels formed in ternary cement blends containing thermally activated paper sludge (APS), fly ash (FA) from coal combustion and Ordinary Portland Cement (OPC) was studied by means of the specific surface area (SSA) and pore-size distribution (PSD), which were measured by the sorption isotherms of nitrogen gas and the BET method. Two differentiated zones in the PSD of the C–S–H gel at ∼10–20nm and ∼5nm were observed. The proportion of such zones depends on the age of hydration and amount of OPC replacement. The incorporation of the additions (APS and FA) clearly revealed an increase in both porosity and SSA. This effect decreased with the progress of hydration together with a refinement of the nano-porous structure of C–S–H. High correlations were found among these nanostructure characteristics of the C–S–H gel and mechanical strengths. [Copyright &y& Elsevier]

The influence of fiber characteristics and calendering on the structure and properties of aramid paper was investigated. Laboratory aramid handsheets were prepared, and the structure and properties of them were investigated by Field Emission Scanning Electron Microscopy (FESEM), Dynamic Mechanical Analysis (DMA), X-ray Diffractometer (XRD) and strength test. A comparison with commerical Nomex papers showed that overdrawn fibers with high initial modulus and film-like fibrids were helpful for improving the interface bonding and mechanical strength of aramid paper. Hot calendering improved the crystallinity, storage modulus and interface bonding of aramid materials, thereby greatly improving the mechanical strength of aramid paper. [ABSTRACT FROM PUBLISHER]

The structural characteristics of cellulose and chalk nanoparticles were studied by the methods of electronic microscopy, laser light scattering, X-ray diffraction, sorption, water retention, and some others. It is shown that nanocellulose consists of rodlike particles having an increased hydrophility. In contrast to the organic nanocellulose, the inorganic nanochalk contains ellipsoidal particles having a relatively low hydrohpility. Paper samples containing cellulose fibers and nanoparticles, as well as flocking and sizing agents, were made and their properties were tested. Testing the mechanical properties of the paper samples showed that the introduction of the hydrophilic cellulose nanoparticles, having a developed surface, decreased the porosity and sharply increased the strength of the final paper. In contrast to this result, chalk nanoparticles did not improve the physicomechanical properties of paper, because of the low bonding between the inorganic particles and the organic cellulose fibrils. [ABSTRACT FROM AUTHOR]

The reutilization of paper mill sludge as filler/reinforcement of polypropylene composites has been evaluated. The results show that the increasing content of sludge in composites resulted in materials with higher Young's modulus, although with lower tensile strength and deformation at break. Thus, in composites submitted to tensile stress paper mill sludge behaved mainly as filler. On the contrary, when materials were submitted to flexural stresses sludge worked partially as reinforcement. The addition of a coupling agent enhanced the fiber-matrix interface. As a result, composite materials with improved mechanical properties, either to tensile, flexural and impact tests were obtained. Considering the mechanical properties of the materials obtained, the substitution of traditional mineral fillers by paper mill sludge is a feasible alternative for composites used in low mechanical demand applications. [ABSTRACT FROM AUTHOR]

The present work shows the suitability of using recovered cardboard boxes for the development of high-performance papers through the use of cellulose nanofibers (CNF) and sodium carboxymethyl cellulose (CMC-Na). CNF were prepared by enzymatic hydrolysis using bleached kraft hardwood pulp, while a commercial grade of CMC-Na was used. Both were added in bulk together with polyethylenimine (PEI) as wet-end additive to improve pulp drainability. The combination of 3 wt% CNF and 7.5 wt% CMC-Na double the breaking length of paper. In addition, the use of 0.4 wt% of PEI significantly decreased the Schopper – Riegler degree, while mechanical properties remained almost at the same level. It was found that it is possible to recover and even increase the properties of recycled papers, with the added advantage that no structural damages were caused on the fibres, increasing the life span and recyclability of paper products. [ABSTRACT FROM AUTHOR]

Aramid paper based on poly ( p -phenylene terephthamide) (PPTA) is a typically excellent insulation material, but the common preparation is complex and tedious. In this work, using the PPTA based aramid nanofibers (ANFs) synthesized by the bottom-up polymerization induced self-assembly process, insulation paper was fabricated through the vacuum assisted filtration without any high pressure or high temperature treatment. Importantly, the ANF paper exhibits improved electrical insulation, desired mechanical strength and good thermal stability, which is attributed to the tightly weaved architecture formed by the nanofibers. [ABSTRACT FROM AUTHOR]

In this paper, polysiloxane is used to modify insulation paper cellulose, and molecular dynamics methods are used to evaluate the glass transition temperature and mechanical properties of the paper before and after the modification. Analysis of the static mechanical performance of the model shows that, with increasing temperature, the elastic modulus of both the modified and unmodified cellulose models decreases gradually. However, the elastic modulus of the modified model is greater than that of the unmodified model. Using the specific volume method and calculation of the mean square displacement of the models, the glass transition temperature of the modified cellulose model is found to be 48 K higher than that of the unmodified model. Finally, the changes in the mechanical properties and glass transition temperature of the model are analyzed by energy and free volume theory. The glass transition temperatures of the unmodified and modified cellulose models are approximately 400 K and 450 K, respectively. These results are consistent with the conclusions obtained from the specific volume method and the calculation of the mean square displacement. It can be concluded that the modification of insulation paper cellulose with polysiloxane will effectively improve its thermal stability. [ABSTRACT FROM AUTHOR]

Through design hierarchical architectures and interlayer interaction, multifunctional macroscopic graphene oxide papers tend to attain outstanding mechanical properties. Three dimensional architectures functionalized graphene oxide papers are self-assembled with zirconium diboride particles and poly(vinyl alcohol, PVA) using vacuum assisted filtration method. Firstly, ternary graphene oxide micro-scale structures are achieved by the addition of zirconium diboride particles. Then, PVA is introduced to enhance the interface interaction between graphene oxide nanosheets and zirconium diboride particles. The results show significant enhancements in fracture strength (~ 200%) and tensile modulus (20–100%) are attained through synergistic effect of ternary graphene oxide structures and interlayer interaction between PVA, graphene oxide and zirconium diboride particles. [ABSTRACT FROM AUTHOR]

To model advanced 3-D forming strategies for paper materials, the effects of environmental conditions on the mechanical behavior must be quantitatively and qualitatively understood. A tensile test method has been created, verified, and implemented to test paper at various moisture content and temperature levels. Testing results for one type of paper for moisture contents from 6.9 to 13.8 percent and temperatures from 23 to 168 degrees Celsius are presented and discussed. Coupled moisture and temperature effects have been discovered for maximum stress. Uncoupled effects have been discovered for elastic modulus, tangent modulus, hardening modulus, strain at break, tensile energy absorption (TEA), and approximate plastic strain. A hyperbolic tangent function is also utilized which captures the entire one-dimensional stress-strain response of paper. The effects of moisture and temperature on the three coefficients in the hyperbolic tangent function may be assumed to be uncoupled, which may simplify the development of moisture- and temperature-dependent constitutive models. All parameters were affected by both moisture and temperature with the exception of TEA, which was found to only be significantly dependent on temperature. [ABSTRACT FROM AUTHOR]

Fiber classification of aramid fibrids was carried out using a Bauer-McNett fiber classifier, and the molecular weight and thermal properties of different sizes of aramid fibrids were determined with viscometry and differential scanning calorimetry (DSC), respectively. Aramid handsheets were made from different sizes of aramid fibrids and aramid short fibers, and the relationship between mechanical strength of aramid handsheets and thermal properties of aramid fibrids was examined. In addition, aramid papers from four different sources were also investigated to elucidate the relationship between their thermal properties and mechanical strength. It was found that aramid fibrids passing through 30-mesh screens and remaining on 50-mesh screens and aramid fibrids with narrower molecular weight distribution are suitable for the production of high-strength aramid papers. Lower crystallinity and wider molecular weight distribution are important contributors to the lower mechanical strength of domestic aramid paper when compared to that of Nomex paper. [ABSTRACT FROM AUTHOR]

Abstract: Fumigants, including methyl bromide and ethylene oxide, are generally used for the preservation of the Korean cultural heritage, especially paper products like letters and books. However, the use of fumigants is banned because of their harmful effects on humans and the environment. Gamma irradiation is being considered as an alternative for the sterilization of insects and fungi in organic products. Therefore, the purpose of this study was to investigate the sterilization effects of radiation and its effect on the mechanical properties of the Korean traditional paper—Hanji. Treatment doses of 9kGy and 8kGy of gamma irradiation inactivated 5 log units of Aspergillus niger and Bacillus cereus spores inoculated on Hanji, respectively. The gamma irradiations up to an absorbed dose of 50kGy resulted in no significant changes in the tensile strength, bursting strength, and appearance of Hanji. These results confirmed that radiation treatment disinfects the Korean traditional paper efficiently without changing its properties and that this treatment could be used to prevent the damage of Korean ancient archives by molds and fungi. [Copyright &y& Elsevier]

Abstract We developed a paper-type electrode for the next-generation wearable devices by complementary hybridization of methyl cellulose and carbon nanotubes (CNTs). The large-scale hybrid paper was fabricated using an incomparably simple and low-cost solution process. Structural features, surface hydrophobicity, and chemical interaction between CNTs and cellulose of the hybrid papers were systematically explored by adjusting the concentration of CNTs. The hybrid papers demonstrated superb mechanical durability even under highly strained conditions such as folding, crumpling and re-flattening regardless of the concentration of CNTs. The electrical properties of the CNTs/methyl cellulose were well-preserved even when folded as origami or submerged in water. [ABSTRACT FROM AUTHOR]

Highlights • LbL technique was conducted to assemble starch PEMs on recycled fibers. • Recycled fibers was also treated by refining as commonly industrial method. • RSM optimized PEMs-treated fibers as mixed with refined pulp on paper properties. • The model predicted acceptable paper strengths at lower-refined fibers loading. Abstract Layer-by-layer (LbL) treated recycled fibers were investigated in mixtures with refined pulp relative to the mechanical properties of paper. The LbL treatments were conducted to assemble consecutive cationic and anionic starch layers on the fibers of old corrugated container (OCC) pulp. Fibers zeta potential was measured to examine the success of LbL treatment. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to reveal the differences between treated and untreated fibers surface and network. Subsequently, the LbL-treated fibers were added to the refined OCC pulps. Optimization of paper (60 ± 3 g m-2 basis weight) strength properties including: tensile index, Scott bond (internal bonding), and ring crush test (RCT) was carried out by response surface methodology (RSM). The meaningful change of zeta potential substantiated cationic/anionic starch layers construction. The AFM results showed that the surface of fibers were covered with starch, which was consistent with deposition of polyelectrolyte multi-layers (PEMs). The surfaces of the LbL-treated fibers were rough in comparison with untreated fibers. The optimization of mechanical parameters using RSM indicated that refining time significantly affected the paper’s mechanical properties. The property values of 44.5 N.m/g tensile index, 149 J/m2 Scott bond, 32 mN RCT, and 245% strain at break were achieved at optimal conditions of 16 min refining time and the addition ratio of 17.6% LbL treated pulp respectively. [ABSTRACT FROM AUTHOR]

Practical applications require scalable, low cost and facile approaches to fabricate coatings that are repellent to liquids and yet are resistant to mechanical impact and abrasion which may occur during service operation of these materials. Here we report fabrication of superhydrophobic (SHP) coatings on paper substrates by one-step spray-coating of fluorinated silica nanoparticles. The coatings were extremely repellent to water and organic liquids with surface tensions higher than ~ 45 mN/m, as demonstrated by the sliding angles that are lower than 5°. The coated paper substrates retained their liquid repellency behavior without any discernable change in their static contact and sliding angles following different mechanical wear tests. Mechanical robustness together with demonstrations in self-cleaning, anti-icing and food-packaging show great promise for the use of fabricated paper substrates in different applications. A significant finding of the present work is that the mechanical robustness of the spray-coated fluorinated silica nanoparticles in the absence of any polymeric matrix/binder was dramatically higher on paper in comparison to flat substrates. These results suggest that the inherent microstructure of the paper provides a suitable matrix for protecting the functionalized nanoparticles against external mechanical effects and present an effective strategy for improving the mechanical robustness of the coatings fabricated by one-step spray-coating of nanomaterials. [ABSTRACT FROM AUTHOR]

The effects of partial or complete replacement of two commercial fillers, carbon black (CB) and silica on cure characteristics, tensile properties, fatigue life, morphological properties, and rubber-filler interaction of paper sludge (PS) filled natural rubber composites were elucidated. Compounding was carried out on a two-roll mill with total filler loading of 30 phr. Results indicate that maximum torque, tensile strength, elongation at break, tensile modulus, and fatigue life increased the cure time while the scorch time decrease with increasing carbon black loading ratio of PS/CB filled natural rubber composites. On the other hand, increased loading of silica in PS/silica weight ratio resulted in an increment in cure time, scorch time, maximum torque, elongation at break, and fatigue life but not significantly altering tensile strength and tensile modulus of the natural rubber composites. In addition, PS/silica filled natural rubber composites exhibit lower maximum torque, tensile properties, and fatigue life compared to the PS/CB filled natural rubber composites. Rubber-filler interaction and SEM micrograph studies proved that the higher interaction between carbon black and natural rubber occurred in PS/CB filled natural rubber composites rather than PS/silica filled natural rubber composites. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated the aging and deterioration of cardboard and Fabriano paper supports painted directly with linseed-oil-based tidanium dioxide paint. The researchers examined the effects of aging by heat or ultraviolet light on the mechanical properties, optical properties, and pH of Fabriano paper and cardboard. Thermogravimetric analysis was used in studying the thermal stability of the paper.

An efficient synthetic route to scalable high-performance graphene paper (G-paper) with high conductivity and excellent mechanical and chemical stabilities has been demonstrated. This paper-like electrode material comprises a poly(vinyl butyral- co -vinyl alcohol- co -vinyl acetate) (P(VB- co -VA- co -VAc)) copolymer adhesion layer and water-dispersible graphene (WDG) active material. A highly conductive, ductile, and mechanically robust G-paper was obtained using the Meyer rod coating method. The P(VB- co -VA- co -VAc) copolymer played an important role in smoothing the G-paper surfaces, resulting in enhanced conductivity of the G-paper. Moreover, the copolymer enhanced the mechanical stability of the G-paper through its strong hydrogen bonding interactions with WDG sheets and cellulose molecules. The as-prepared G-paper coated with P(VB- co -VA- co -VAc) exhibited low sheet resistance (115 Ω/sq), high tensile strength (37.2 MPa), good bending stability, and excellent acid-base resistance. [ABSTRACT FROM AUTHOR]

In the present work the evolution of physical and mechanical properties of papers and nanopapers is studied. Handsheets made of eucalyptus fibres reinforced with 0, 25, 50, 75 and 100 wt% of nanofibrillated cellulose (NFC) content were fabricated using a Rapid Köthen-like equipment. The obtained papers and nanopapers were physical- and mechanically-characterized. The results showed a significant increase in density and a reduction of porosity in the samples during their transition from paper to nanopaper; besides, nanopapers were more transparent and smoother than normal papers. These physical changes where more evident with increasing amounts of NFC. Regarding mechanical properties, nanopapers with a 100 wt% content of NFC improved their strength and rigidity in 228 and 317 %, respectively, in comparison with normal papers. The evolution of strength and rigidity from paper to nanopaper was linear in relation to the amount of NFC, which means that the ultimate tensile strength was mainly dependant on nanofibril failure. [ABSTRACT FROM AUTHOR]

The ability to increase the filler content of paper without significantly sacrificing its mechanical strength is of high interest for papermakers. In this work, three samples of ground calcium carbonate (GCC), differing in size and in brightness, modified with silica via the sol-gel method, were used as fillers in papermaking. Handsheets were produced using a eucalyptus kraft pulp furnish and with a filler amount near 20%. It was found that not only were the strength properties of the handsheets produced with the modified GCCs always significantly better than those obtained with the unmodified GCCs (e.g., the tensile index exhibited improvements of 16 to 20%), but bulk also was increased (by 7 to 13%). Some decreases in the light scattering and opacity values were noted when using the modified GCC, but the brightness was roughly the same. The enhanced fiber-to-filler bonding may be attributed to the hydrogen bonding between the cellulosic fibers and the hydroxyl groups of the silica coating the calcium carbonate particles. [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]

Abstract: The use of paper-mill residuals in concrete formulations was investigated as an alternative to landfill disposal. The mechanical and durability properties of concrete containing paper-mill residuals collected from a wastewater treatment-plant were evaluated. Class F fly ash was used as a replacement for Portland cement (PC) when incorporated into concrete mixtures containing paper-mill residuals and the resulting products were compared to normal concrete. Compressive, splitting tensile, flexural strength and drying shrinkage tests were carried out to evaluate the mechanical properties for up to 90days. Rapid chloride-permeability tests and initial surface-absorption tests were carried out at 28days to determine the durability properties. Concrete containing paper-mill residuals showed improvement in the durability test results when PC was replaced with class F fly ash. [ABSTRACT FROM AUTHOR]

The study compares conventional and recycled office paper, based on experimental work. To confront the market needs, we have to find alternatives in respond to enormous necessity and application of office paper. Therefore, one way in dealing with the problem is to replace or just decrease the use of paper made entirely from primary components, mainly wood fibres (deciduous and conifer). We analysed mechanical, optical, structural and microscopic properties of conventional and recycled office papers. Experiments were performed on three conventional and three recycled office papers attainable on the market. The results obtained from measurements confirm the presumption that the mechanical and surface properties of recycled office paper can be collated and they discern from conventional office paper. [ABSTRACT FROM AUTHOR]