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Due to a shortage of resources, exploring new biomass fillers has become critical for paper making. In this study, we reported an eco-friendly strategy for fabricating low-cost and efficient recycled paper with high mechanical properties using corrugated cardboard waste paper and harmless municipal sludge (HMS). First, the characteristics of HMS, including the particle size, pH, specific surface area, organic functional groups and organic component content, were analyzed. Then, the influence of the amount of HMS on the properties of the recycled paper was studied. Finally, the strengthening mechanism of biomass filling recycled paper was discussed. The results showed that HMS, a biomass filler for recycled paper preparation, exhibited excellent physical and chemical properties, with a median particle size of 6.395 μm, a surface area of 39.974 m2 g−1 and organic functional groups. The tensile index of the recycled paper with 30 % HMS was 13.10 Nm/g, which was 16.4 % greater than that of the unfilled paper and showed better thermal stability. This excellent performance could be attributed to the uniform distribution of HMS on the fiber surface, which improved the accessibility of hydrogen bond formation between fibers. Thus, this study proved that HMS was an excellent biomass filler for producing recycled paper. [ABSTRACT FROM AUTHOR]

The effect of shredded waste office paper was considered when producing one-layered particleboard. Five different mixing ratios of shredded waste office paper/wood particles were used (0/100, 25/75, 50/50, 75/25, and 100/0) and two amounts of urea formaldehyde (UF) resin (10% and 15%). The boards were tested for their physical and mechanical properties, including modulus of elasticity (MOE), bending strength (MOR), and internal bond (IB) strength, in accordance with the European Norm (EN) standards. All properties of the boards were found to be improved via increasing the resin content. The 15% UF-bonded board with 100% wood particles had the highest MOR, whereas the board containing 100% wastepaper for 15% UF had the highest MOE. However, there was no statistical difference between the board types. Although increasing wastepaper content in the board negatively affected the IB, the usage of wastepaper up to 25% was shown to be acceptable as a raw material in the production of particleboard. None of the prepared boards met the EN 312 (1999) requirements for thickness swelling. The boards made from shredded waste office paper were more suitable for dry and indoor use. [ABSTRACT FROM AUTHOR]

The primary aim of this research was to explore the feasibility of producing environmentally friendly composite materials by employing diverse hybrid matrices consisting of dammar natural resin, supplemented with small proportions of two synthetic resins: one epoxy and the other acrylic. A blend of paper and chicken feathers served as the reinforcing elements. The fabrication of these composite materials utilized a hand layup technique. Targeted for applications in the furniture industry or interior design, their mechanical properties were assessed through various tests. Specimens were obtained from the manufactured samples and subjected to evaluations for tensile strength, compression, flexure, vibrations, Shore hardness, and water absorption. Results indicated that irrespective of the testing method employed, the mechanical strength properties exhibited a decline with an increase in the percentage of dammar in the hybrid resins, whereas the elasticity properties demonstrated an increase with this percentage.

Hemp hurd fiber, a low-value waste stream from the hemp industry, has potential downstream applications as an alternative to non-renewable plastics for single-use food service ware and packaging applications. Packaging paper substrates made from chemically pulped hemp hurd, mixed in varying ratios with bleached thermomechanical radiata pine pulp were developed and tested. Handsheets were characterized using several mechanical property tests including tensile strength, tearing resistance, burst strength, short-span compression, ring crush, together with Gurley air resistance, contact angle, and Cobb60 tests. Generally, addition of hemp hurd fibers significantly improved handsheet mechanical properties. Hot-pressing of the handsheets so as to approximate molded fiber thermoforming further enhanced their performance, with pure hemp hurd handsheets having the highest mechanical properties and barrier performance. A prototype was successfully thermoformed from hemp fiber, demonstrating overall feasibility of this fibre source for molded fibre objects.

This research provides an in-depth assessment of two paper yarn variants, examining their structural, functional, and performance characteristics. These yarns demonstrated favorable properties, including suitable linear density, twist, typical cellulosic functional groups as confirmed by Infrared spectroscopy, minimal hairiness, moisture transfer, and creditable mechanical strength. These yarns have flat layered cross-sections and grooved longitudinal surfaces. In addition, a low hairiness index (1.3–1.33) further acknowledged their smooth surface. Their remarkable evenness (15.86% and 7.08%) supported their effective wicking properties. Despite average breaking strength (0.77 cN/dTex and 1.05 cN/dTex) and moderate elongation, these yarns exhibited exceptional water-washing resistance and retained over 89% breaking strength after 15 washes. This study ranks these paper yarns as highly suitable for durable clothing fabrics, providing promising sustainable alternatives in the textile industry.

The effect of shredded waste office paper was considered when producing one-layered particleboard. Five different mixing ratios of shredded waste office paper/wood particles were used (0/100, 25/75, 50/50, 75/25, and 100/0) and two amounts of urea formaldehyde (UF) resin (10% and 15%). The boards were tested for their physical and mechanical properties, including modulus of elasticity (MOE), bending strength (MOR), and internal bond (IB) strength, in accordance with the European Norm (EN) standards. All properties of the boards were found to be improved via increasing the resin content. The 15% UF-bonded board with 100% wood particles had the highest MOR, whereas the board containing 100% wastepaper for 15% UF had the highest MOE. However, there was no statistical difference between the board types. Although increasing wastepaper content in the board negatively affected the IB, the usage of wastepaper up to 25% was shown to be acceptable as a raw material in the production of particleboard. None of the prepared boards met the EN 312 (1999) requirements for thickness swelling. The boards made from shredded waste office paper were more suitable for dry and indoor use.

The mechanical properties for paper sheets composited with glucose (Glc), methyl cellulose (MC), and carboxymethyl cellulose (CMC) were investigated. The paper composites were prepared by immersing paper sheets in aqueous solutions of these materials and drying at 100 °C for 30 min. The stress–strain curves for these paper composites were measured by a uniaxial tensile apparatus with a stretching speed of 2 mm/min. The breaking stress and strain for untreated paper were 24 MPa and 0.016, respectively. The paper composites demonstrated stress–strain curves similar to the untreated paper; however, the breaking point largely differed for these composites. The breaking strain and breaking stress for the Glc composite slightly decreased and those for the MC composite gradually increased with the concentration of materials composited. Significant increases in the mechanical properties were observed for the CMC composite. The breaking stress, breaking strain, and breaking energy for the 3 wt.% CMC composite were 2.0-, 3.9-, and 8.0-fold higher than those for untreated paper, respectively. SEM photographs indicated that the CMC penetrated into the inner part of the paper. These results strongly suggest that the mechanical improvement for CMC composites can be understood as an enhancement of the bond strength between the paper fibrils by CMC, which acts as a bonding agent. It was also revealed that the breaking strain, breaking stress, and breaking energy for the CMC composites were at maximum at the first cycle and decreased gradually as the immersion cycles increased. [ABSTRACT FROM AUTHOR]

The materials to produce concrete blocks (sand, gravel, and cement) are limited resources that are becoming scarce over time due to their increasing demand in construction. On the other hand, the waste of glass and paper is progressively increasing without being fully utilized through recycling. Therefore, the objective of this scientific research is to evaluate the influence on the mechanical properties of masonry concrete blocks made with recycled glass and paper particles. Likewise, the sample was non-probabilistically selected for convenience, consisting of 192 concrete blocks manufactured with additions of 3% (2% glass particles and 1% recycled paper), 6% (4% glass particles and 2% recycled paper), and 9% (6% glass particles and 3% recycled paper), as well as concrete blocks manufactured without additions. According to the results obtained, at 3%, 6%, and 9% addition of glass and paper particles, the absorption decreased by 4.94%, 3.398%, and 3.52% respectively. However, the warping increased between 1.7mm and 1.8mm, while the compressive strength (f'c) increased to 75kg/cm2, 82kg/cm2, and 77kg/cm2, respectively. Similarly, the axial compressive strength (f'm) increased to 91.22kg/cm2, 94.45kg/cm2, and 92.80kg/cm2, and the diagonal compressive strength (V'm) increased by 8.90kg/cm2, 9.70kg/cm2, and 9.70kg/cm2. Nevertheless, the manufacturing cost of masonry units showed a progressive reduction with the amount of glass + paper addition, amounting to 0.57 USD, 0.55 USD, and 0.53 USD. It was also determined that the optimal addition of these materials in the concrete mix in terms of cost and strength is 9% (glass + paper), resulting in compressive strengths of 77kg/cm2, 92.8kg/cm2, and 9.70kg/cm2, with a cost of 0.53 USD per unit. In conclusion, it can be affirmed that adding glass and recycled paper particles in the production of concrete blocks for use in loadbearing masonry walls positively influences the physical and mechanical properties of the blocks. Additionally, it allows for a reduction in manufacturing costs, leading to significant savings for builders. [ABSTRACT FROM AUTHOR]

The influences of nano-chitosan and cationic polyacrylamide (cPAM) on the optical and mechanical properties of paper made from chemi-mechanical pulp (CMP) were investigated. Bleached chemi-mechanical pulp (CMP) was selected as the control sample. The cPAM was considered at four levels (0%, 0.25%, 0.5%, and 0.75%), while chitosan was added to the CMP suspension at three levels (0%, 1%, and 2%). Paper test specimens were prepared according to TAPPI standards with a basis weight of 60 g/m2, and their optical and mechanical properties were measured. The results indicated that the opacity, greenness, tear strength, burst strength, and Gurley seconds were increased, whereas brightness, water absorption, and a* factor were decreased by increasing the amount of cPAM. Adding chitosan to CMP increased the a* factor, tear strength, breaking length, burst strength, Gurley seconds, water absorption, and greenness in the resulting paper. When polyacrylamide and nano-chitosan were added simultaneously to CMP, the brightness, water absorption, and greenness of the resulting paper decreased, but opacity, burst strength, tear strength, and air resistance had an appropriate increase. In all treatments, the best results were found at 1% chitosan and 0.5% cPAM due to favorable optical and mechanical properties.

Abstract This research uses WP to investigate the effect of two types of Shredded Waste Paper (SWP) comprising Shredded Copier Waste Paper (SCPWP) and Shredded Cardboard Waste Paper (SCBWP) as additives on the properties of concrete and the structural behaviour of Reinforced Concrete Beam (RCB). The slump, compressive, flexural, and splitting tensile strengths increase by 4–13% for 5–10% addition of SCPWP and decrease by 16–23% for 15% addition of SCPWP compared to 0% addition. For SCBWP, the slump, compressive, flexural and splitting tensile strengths increase by 10–23% for 5–10% addition and decrease by 15–21% for 15% addition compared to 0% addition. 15% of SCPWP and SCBWP addition records the highest effect in water absorption and efflorescence, showing 11% and 10.28% increases with 15% addition of SCBWP and SCPWP. Scanning electron microscope (SEM) analysis reveals that the crack is repaired, and the presence of calcium hydroxide (Ca(OH)2) and calcium–silicate–hydrate (C–S–H) links enhances the concrete strength. The addition of 10% SCPWP and 10% SCBWP in the concrete mixtures improves the structural behaviour of RCB with stirrup spacing (SS) = 100 mm (full), 150 mm and 200 mm (reduced) by increasing the load and reducing the deflection. Apart from that, the concrete bending and shear strains also increase by 44.17% and 34.9%. The failure mode of the RCB changes from shear to bending. This study indicates that SCPWP and SCBWP can be used as additives in concrete at 5% and 10%, and 10% for RCB with significant strength and structural improvement.

Xuan paper is one of the most famous handmade papers in China and is an important paper for conservation. However, the evenness of Xuan paper has not yet received much attention. In this study, the distribution of the in-plane grammage and mechanical properties of Xuan paper are measured. It is found that the distribution of the in-plane grammage and mechanical properties of Xuan paper is uneven. In the handmade direction, the grammage and mechanical properties of Xuan paper are overall largest in the lower area, followed by the upper and middle areas. The sheet forming process of Xuan paper has an important effect on the distribution of in-plane grammage, mechanical properties, and fiber orientation of Xuan paper. The folded state has a negative effect on the mechanical properties of the folded area of Xuan paper. This study will help raise awareness of the unevenness in physical properties of Xuan paper, which is important in both conservation and research applications. [ABSTRACT FROM AUTHOR]

Following the surge in power loads and continuous improvement in the voltage level, insulating papers' mechanical and electrical properties face new challenges. However, traditional inefficient “tentative” trial and error experiments are formidable to rapidly and efficiently prepare cellulose composite insulating paper because the direct scientific theory or simulation guidance is insufficient. To solve this problem, the nano-silica(nano-SiO2)/polyimide(PI)/cellulose composite models were designed and their mechanical, and dielectric properties were predicted by molecular dynamics (MD) simulation. The preparation of corresponding nano-SiO2/PI/cellulose insulating paper was guided by the MD simulation results and their surface morphology, mechanical properties, and electrical properties were investigated. The experimental results are in good agreement with the MD simulation results and confirmed that P3 insulating paper possesses the best comprehensive performance, and its tensile strength, relative permittivity, dielectric loss, volume resistivity, and breakdown strength are 71.44 MPa, 2.39, 0.2%, 5.16 × 1015 Ω∙m, and 75.8 kV∙mm−1, respectively. This work proves the feasibility and effectiveness of using MD simulation to guide the development of new insulating papers, and compared with the existing traditional preparation methods, this method is expected to be applied to study various new materials in the future and promote the vigorous development of new materials.

The development of new construction materials is a crucial issue in the building construction industry, as it is one of the most energy and resource-intensive industries. Paper has played a significant role in daily activities since its creation. a wide range of applications thanks to its adaptable qualities. Paper waste can be found in a variety of places, including newspapers, offices and schools. Paper waste is a rich source of fibre and can be utilised as a building material. Utilization of paper wastes can help to reduce pollution and waste in the environment. The purpose of this review study is to highlight and examine some current studies that look into the potential applications of post-consumer paper waste in concrete specimens. The review had been conducted on the research paper between the year 2010 till 2023, paper waste does have potential to be incorporated with cementbased material with the right formulation and percentages. This review data focused on the mechanical properties of concrete. [ABSTRACT FROM AUTHOR]

The mechanical properties for paper sheets composited with glucose (Glc), methyl cellulose (MC), and carboxymethyl cellulose (CMC) were investigated. The paper composites were prepared by immersing paper sheets in aqueous solutions of these materials and drying at 100 °C for 30 min. The stress–strain curves for these paper composites were measured by a uniaxial tensile apparatus with a stretching speed of 2 mm/min. The breaking stress and strain for untreated paper were 24 MPa and 0.016, respectively. The paper composites demonstrated stress–strain curves similar to the untreated paper; however, the breaking point largely differed for these composites. The breaking strain and breaking stress for the Glc composite slightly decreased and those for the MC composite gradually increased with the concentration of materials composited. Significant increases in the mechanical properties were observed for the CMC composite. The breaking stress, breaking strain, and breaking energy for the 3 wt.% CMC composite were 2.0-, 3.9-, and 8.0-fold higher than those for untreated paper, respectively. SEM photographs indicated that the CMC penetrated into the inner part of the paper. These results strongly suggest that the mechanical improvement for CMC composites can be understood as an enhancement of the bond strength between the paper fibrils by CMC, which acts as a bonding agent. It was also revealed that the breaking strain, breaking stress, and breaking energy for the CMC composites were at maximum at the first cycle and decreased gradually as the immersion cycles increased.

The high production of paper, followed by a more significant concern with environmental and economic issues, has led to greater relevance to paper recycling and its raw uses as composite filler. Composites of polypropylene with 10, 20, and 30 wt.% of recycled office waste paper were produced by injection molding and characterized by mechanical and thermal properties. All composites presented a slight reduction of 15°C in thermal stability compared to the polymeric matrix. Moreover, as the filler amount increased, the degree of crystallinity was reduced proportionally. The mechanical test showed similar tensile strength values among neat polymer andcomposites but also showed an increase in the composite’s tensile modulus, related to the stiffness of the natural filler. The composite with a higher percentage of waste paper (30 wt.%) maintained equivalent properties as neatpolypropylene and other composites (10 and 20 wt.%). Thus, 30 wt.% composites proved to be an excellent material with less synthetic polymer percentage, keeping thermal and mechanical properties comparable to the neat PP.Furthermore, this composite does not need chemical treatment or additives harmful to the environment. It is suitable for future applications in various plastic products such as packaging and domestic utensils.

The objective of this study was to better understand the effect of micro/nanofibrils added as reinforcement on paper handsheets, their physical-mechanical performance and barrier properties, and to determine the ideal cellulose nanofibrils (CNF) proportion to increase such paper properties. Mechanically produced CNF were added at increasing amounts (0%, 2%, 5%, 8% and 10%) to commercial Eucalyptus pulp to produce paper handsheet samples. Morphology, crystallinity, physical-mechanical and air barrier properties of the paper handsheets were evaluated. The results suggested that adding CNF has decreased the presence of empty spaces inside and on the surface of the paper handsheets by up to 61% due to the interaction between fibers and nanofibrils. The paper handsheets became denser, more compact and resistant to passage of air, as well as with greater mechanical performance with higher CNF content (10%). The bursting index is approximately 5 times higher on paper with addition of 10% of CNF compared to control paper handsheets. There were significant gains in the studied properties without any change in CNF/fibers surface charge or the use of any cationic polymer to assist the retention of nanofibrils and fibers. This study highlights the potential of CNF as additives in papermaking process, increasing its properties.

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The addition of sugarcane pulp sand (SCPS) and paper grain sand (PGS) to concrete bricks was proven effective in this study. This research not only investigated the engineering of incorporating SCPS and PGS into concrete bricks to build lightweight bricks but also examined the possibility of substituting fine aggregates with agricultural and industrial wastes to safely dispose of or recycle wastes. Concrete bricks were subjected to multiple tests, such as scanning electron microscopy, to evaluate their compressive strength, flexural strength, bulk density, apparent porosity, water absorption, unit weight, and microstructure. The primary objective of this research was to determine the optimal blend of crushed SCPS and PGS to replace fine aggregates. In accordance with the current study, compressive strength was increased when the ideal mixing ratio of fine aggregate substitution with ground SCPS and PGS was achieved. Fine aggregate replacement ratios from up to 10 %, 20 %, 30 % and 40 % waste products. In addition to the use of wastes, replacing fine aggregates with agricultural and industrial wastes. Compared with the control sample, the bricks with SCPS + PGS-10 % demonstrated significantly better mechanical characteristics after 28 days, with compressive strength increasing by 8.52 % and flexural strength increasing by 18.43 %. Microstructure research validated the effectiveness of SCPS + PGS in improving brick strength and unit weight. In addition to production, generic nonstructural light bricks reduce overall carbon emission, agricultural and industrial wastes and required construction materials, solving environmental pollution problems caused by construction waste in the future.

This study aims to comprehensively examine the influence of three distinct additives, namely carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC), and cellulose nanofibers (CNF), on the performance enhancement of corrugated base paper. For this purpose, steam‐exploded rice straw was treated with varying concentrations (2, 4, 6, 8, and 10 wt%) of CMC, HPMC and CNF. Analysis of the rice straw pre and post expansion, as well as the modified corrugated base paper, was conducted using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), tensile performance testing, and scanning electron microscopy (SEM). Results indicated that adding CMC, CNF, and HPMC to corrugated base paper significantly improved bonding between paper layers, particularly at 2 %, 6 %, and 8 % concentrations, respectively. This enhancement notably increased tensile strength and elastic modulus of the corrugated base paper. Tensile performance saw increases of 57.76 %, 59.01 %, and 60.25 %, while elastic modulus showed increments of 52.7 %, 9.4 %, and 136.69 %, respectively. These findings provide valuable insights for the preparation of corrugated base paper and highlight the potential of CMC, HPMC, and CNF in enhancing paper mechanical properties. [ABSTRACT FROM AUTHOR]

A significant increase in the consumption of recycled fiber products has been observed worldwide, and the industry is forced to solve the challenges of recycled fiber quality and add strength agents and/or virgin fibers to reach sufficient properties. In order to investigate whether the mechanical and air permeability properties of waste fiber (WF) material can be significantly improved by adding wood kraft fibers (KF), hemp soda fibers (HF), and ammonium persulfate oxidated cellulose nanofibrils (CNF), different fiber blends were prepared and tested. Results revealed the excellence of hemp fibers over wood fibers regarding the improvement of WF products. The results of WF after the addition of 10% mixed fibers (KF + HF) were higher than the results of a 50% KF addition. The impact of CNF depended on fiber composition and properties. A formula for modeling the CNF impact on different fiber compositions was proposed. Obtained fiber material samples showed suitability for home composting, thus contributing to the goals of the European Green Deal regarding reducing landfill waste and the development of cleaner products. [ABSTRACT FROM AUTHOR]

Oil palm empty fruit bunch (EFB), an abundant fiber material obtained after extracting the oil from the strands, is classified as short fiber which needs supporting agent in order to enhance its mechanical strength for papermaking purpose. The main objective of this research is to investigate the effects of beaten EFB fibers incorporated with microcrystalline cellulose (MCC). Two types of beaten EFB fibers from 500 to 1000 revolutions were applied with MCC. The selected percentage of MCC addition was 0%, 3%, 6%, and 9%. Papermaking process was conducted according to TAPPI Standard T 205 sp-02. By incorporating MCC into EFB fibers, the porosity of the paper decreased while the opacity increased. Paper with 6% of MCC addition had the highest mechanical properties especially on the tensile strength. Beating effect was also found as a great factor in influencing the strength of the papers made from EFB fibers with MCC. Beating revolution of 500 showed excellent properties for tear, burst, and folding endurance. Based on physical, mechanical, and optical properties, the produced paper is found potential in the manufacture of writing or high-quality printing grade paper.

The primary aim of this research was to explore the feasibility of producing environmentally friendly composite materials by employing diverse hybrid matrices consisting of dammar natural resin, supplemented with small proportions of two synthetic resins: one epoxy and the other acrylic. A blend of paper and chicken feathers served as the reinforcing elements. The fabrication of these composite materials utilized a hand layup technique. Targeted for applications in the furniture industry or interior design, their mechanical properties were assessed through various tests. Specimens were obtained from the manufactured samples and subjected to evaluations for tensile strength, compression, flexure, vibrations, Shore hardness, and water absorption. Results indicated that irrespective of the testing method employed, the mechanical strength properties exhibited a decline with an increase in the percentage of dammar in the hybrid resins, whereas the elasticity properties demonstrated an increase with this percentage. [ABSTRACT FROM AUTHOR]

Expansive soil exhibits significant swellings and shrinkages, which may result in severe damage or the collapse of structures built upon it. Calcium-based admixtures, such as lime, are commonly used to improve this problematic soil. However, traditional chemical additions can increase significant environmental stress. This paper proposes a sustainable solution, namely, the use of lignin fiber (LF) from the paper industry to partially replace lime as an amendment for expansive soils. Both the macroscopic and microscopic characteristics of the lignin fiber-treated expansive soil are extensively studied. The results show that the mechanical properties of expansive soil are improved by using lignin fiber alone. Under the condition of an optimal dosage of 8%, the compressive strength of lignin fiber-modified soil can reach 193 kPa, the shear strength is increased by 40% compared with the untreated soil, and the water conductivity is also improved with the increase in dosage. In addition, compared with 2% lime-modified soil, the compressive strength of 8% lignin fiber- and 2% lime composite-treated expansive soil increased by 50%, the cohesion increased by 12%, and the water conductivity decreased significantly. The microstructure analysis shows that at an 8% lignin fiber content, lignin fibers interweave into a network in the soil, which effectively enhances the strength and stability of the improved soil. Simultaneously, the fibers can form bridges across the adjacent micropores, leading to the merging of pores and transforming fine, dispersed micropores into larger, connected macropores. Lime promotes the flocculation of soil particles, forming larger aggregates and thus resulting in larger pores. The addition of fibers exerts an inhibitory effect on the flocculation reaction in the composite-improved soil. In conclusion, lignin fibers are an effective addition used to partially replace calcium admixture for the treatment of expansive soil, which provides a sustainable and environmentally friendly treatment scheme for reducing industrial waste. [ABSTRACT FROM AUTHOR]

The demand for high-grammage paper, 150 g/m2 or more, is increasing for product protection and aesthetic value. Fold cracking, resulting from high mechanical pressure during folding, considerably decreases the economic feasibility of such products for papermaking companies. Fold cracking can be reduced through creasing, but defects possibly occur as fiber bonds are broken. In this study, the fold cracking of high-grammage paper that was not treated through creasing was explored. The mechanical and folding properties of six types of pulp fibers were evaluated based on their beating degree. The fines content of the fiber differed according to the beating condition. Using pulp with low fines content improved the folding properties. The mechanical properties of hardwood pulp were enhanced with increased beating degree. The mechanical properties of softwood pulp were considerably increased, and fold cracking occurred with increasing beating degree. Therefore, to improve the fold cracking, beating should be applied appropriately, following the type and mixing ratio of pulp fibers. Finally, softwood pulp mixing is proposed as a strategy to control fold cracking while maintaining the unique characteristics of high-grammage paper. [ABSTRACT FROM AUTHOR]

A significant increase in the consumption of recycled fiber products has been observed worldwide, and the industry is forced to solve the challenges of recycled fiber quality and add strength agents and/or virgin fibers to reach sufficient properties. In order to investigate whether the mechanical and air permeability properties of waste fiber (WF) material can be significantly improved by adding wood kraft fibers (KF), hemp soda fibers (HF), and ammonium persulfate oxidated cellulose nanofibrils (CNF), different fiber blends were prepared and tested. Results revealed the excellence of hemp fibers over wood fibers regarding the improvement of WF products. The results of WF after the addition of 10% mixed fibers (KF + HF) were higher than the results of a 50% KF addition. The impact of CNF depended on fiber composition and properties. A formula for modeling the CNF impact on different fiber compositions was proposed. Obtained fiber material samples showed suitability for home composting, thus contributing to the goals of the European Green Deal regarding reducing landfill waste and the development of cleaner products.

The demand for particleboard has been increasing over the years. Currently, most particleboards are produced from wood which may not be sustainable in the long term. Therefore, there is need of exploring alternative materials such as making particleboards from waste materials. This study investigated the mechanical properties of particleboard consisting of waste leather shavings and waste papers blended together by unsaturated polyester. A single-layered particleboards were manufactured using compression method. Different resin contents (60%, 70%, 80%, and 90%) and leather/paper ratios (100:0, 25:75, 50:50, 75:25) were used to determine the effects on the mechanical properties (internal bond, bending strength, compression, and impact strength) of fabricated boards. From the results of this study, it was found that leather shavings and waste papers can be used as alternative raw materials for particleboard production and that mechanical properties were depended on the resin content and the blend ratio. Also, mechanical properties were reduced with resin content increment, except for impact strength, and improved by high paper blend ratio. It could be concluded that the produced particle panels could be used for indoor application or interior equipping. Additionally, it is recommended that further studies can be done on morphological analysis to establish the bonding between the particles and matrix.

This review focuses on polymeric waste-paper composites, including state-of-the-art analysis with quantitative and qualitative discussions. Waste paper is a valuable cellulose-rich material, produced mainly from office paper, newspaper, and paper sludge, which can be recycled and returned to paper production or used in a new life cycle. A systematic literature review found 75 publications on this material over the last 27 years, with half of those published during the last five years. These data represent an increasing trend in the number of publications and citations that have shown an interest in this field. Most of them investigated the physicomechanical properties of composites using different contents of raw waste paper or the treated, modified, and cellulose-extracted types. The results show that polyethylene and polypropylene are the most used matrices, but polylactic acid, a biodegradable/sourced polymer, has the most citations. The scientific relevance of waste-paper composites as a subject includes the increasing trend of the number of publications and citations over the years, as well as the gaps identified by keyword mapping and the qualitative discussion of the papers. Therefore, biopolymers and biobased polymers could be investigated more, as well as novel applications. The environmental impact in terms of stability and degradation should also receive more attention regarding sustainability and life cycle analyses. [ABSTRACT FROM AUTHOR]

The high production of paper, followed by a more significant concern with environmental and economic issues, has led to greater relevance to paper recycling and its raw uses as composite filler. Composites of polypropylene with 10, 20, and 30 wt.% of recycled office waste paper were produced by injection molding and characterized by mechanical and thermal properties. All composites presented a slight reduction of 15°C in thermal stability compared to the polymeric matrix. Moreover, as the filler amount increased, the degree of crystallinity was reduced proportionally. The mechanical test showed similar tensile strength values among neat polymer andcomposites but also showed an increase in the composite's tensile modulus, related to the stiffness of the natural filler. The composite with a higher percentage of waste paper (30 wt.%) maintained equivalent properties as neatpolypropylene and other composites (10 and 20 wt.%). Thus, 30 wt.% composites proved to be an excellent material with less synthetic polymer percentage, keeping thermal and mechanical properties comparable to the neat PP. Furthermore, this composite does not need chemical treatment or additives harmful to the environment. It is suitable for future applications in various plastic products such as packaging and domestic utensils. [ABSTRACT FROM AUTHOR]

Expansive soil exhibits significant swellings and shrinkages, which may result in severe damage or the collapse of structures built upon it. Calcium-based admixtures, such as lime, are commonly used to improve this problematic soil. However, traditional chemical additions can increase significant environmental stress. This paper proposes a sustainable solution, namely, the use of lignin fiber (LF) from the paper industry to partially replace lime as an amendment for expansive soils. Both the macroscopic and microscopic characteristics of the lignin fiber-treated expansive soil are extensively studied. The results show that the mechanical properties of expansive soil are improved by using lignin fiber alone. Under the condition of an optimal dosage of 8%, the compressive strength of lignin fiber-modified soil can reach 193 kPa, the shear strength is increased by 40% compared with the untreated soil, and the water conductivity is also improved with the increase in dosage. In addition, compared with 2% lime-modified soil, the compressive strength of 8% lignin fiber- and 2% lime composite-treated expansive soil increased by 50%, the cohesion increased by 12%, and the water conductivity decreased significantly. The microstructure analysis shows that at an 8% lignin fiber content, lignin fibers interweave into a network in the soil, which effectively enhances the strength and stability of the improved soil. Simultaneously, the fibers can form bridges across the adjacent micropores, leading to the merging of pores and transforming fine, dispersed micropores into larger, connected macropores. Lime promotes the flocculation of soil particles, forming larger aggregates and thus resulting in larger pores. The addition of fibers exerts an inhibitory effect on the flocculation reaction in the composite-improved soil. In conclusion, lignin fibers are an effective addition used to partially replace calcium admixture for the treatment of expansive soil, which provides a sustainable and environmentally friendly treatment scheme for reducing industrial waste.

Paper-based friction material is a typical paper-based composite that is usually cured via hot-pressing. This curing method does not account for the effect of pressure on the matrix resin, resulting in uneven distribution of resin in the material and reducing the mechanical properties of friction materials. To overcome the above shortcomings, a pre-curing method was introduced before hot-pressing, and the effects of different pre-curing degrees on the surface morphology and mechanical properties of paper-based friction materials were studied. The pre-curing degree significantly affected the resin distribution and interfacial bonding strength of the paper-based friction material. When the material was cured at 160 °C for 10 min, the pre-curing degree reached 60%. At this point, most of the resin was in a gel state, which could retain abundant pore structures on the material surface without causing mechanical damage to the fiber and resin matrix during hot-pressing. Ultimately, the paper-based friction material exhibited improved static mechanical properties, decreased permanent deformation, and reasonable dynamic mechanical properties.