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Highlights As is well known, Laser print paper is usually produced with high‐quality chemical wood pulp. The laser print waste paper fiber (LPWF) is a high‐quality secondary fiber, and the research and development of high‐value utilization technology for laser print waste paper has attracted much attention in the field of renewable resource recycling. In this study, LPWF was used to reinforce poly(lactic acid) (PLA) composites in the field, and the composites were modified with bioenzyme, cationic polyacrylamide (CPAM), and nano‐silicon carbide (Nano‐SiC) to enhance the interfacial compatibility of LPWF/PLA composites. The study systematically investigated the effects of various modification methods on the characteristics and degradability of composites made from laser print waste paper fiber reinforced PLA resin matrix. The results showed that the mechanical properties of the composites treated with CPAM and Nano‐SiC were significantly improved, with tensile strengths of 54.3 and 59.5 MPa, and flexural strengths of 85.1 and 91.5 MPa, respectively, and the water absorption of the composites was reduced after the modification treatment, while the thermal stability was improved. The degradation performance of the composites in various water environments indicated that the inclusion of LPWF accelerated the water degradation rate of the composites, with the maximum degradation rate of the composite reaching 1.26% in 30 days. Laser print waste paper is an excellent quality recyclable fiber resource. Four modifiers were used to modify LPWF/PLA composites. Characteristics and degradability of the composites were investigated. Significantly improved properties of CPAM and Nano‐SiC modified composites. The degradation rate of composites is increased by the addition of LPWF. [ABSTRACT FROM AUTHOR]

It is well-known that energy consumption is increasing around the world on a daily basis. In the construction sector, a highly effective solution for reducing energy consumption involves exploring both modern and traditional buildings designed to adapt to climate changes. One promising approach is to use paper waste and bio-sourced materials as the basis for insulation. The purpose of this study was to improve the sustainability of buildings by using recycled waste materials that have a positive impact on the environment, people, and the economy. A novel insulating material composed of recycled paper waste and Ampelodesmos mauritanicus leaves and fibers was developed and used in non-load-bearing elements. The paper waste was transformed into pulp and mixed with the bio-sourced materials to create a composite material that exhibits excellent insulation properties. The resulting material is lightweight, durable, and cost-effective. Furthermore, different mechanical and thermal analyses were performed on specimens with varying dosage ratios. The results showed that the developed material has good thermal insulation, with a value of 0.027 W/m.K. [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.

Natural product-based noise-absorbing composite can be an alternative to replace synthetic fiber because of its advantages of high strength, toughness, low price, and abundance to reduce noise. The materials used were pineapple leaf fibers with paper waste. This research aims to study the advantage of natural products to reduce noise by analyzing the coefficient of sound absorption and impact strength to evaluate the absorbing composite. The composites were tested with the Charpy method with ISO 11654 standard and ASTM E23 for sound absorption and impact strength. Sound absorption was carried out using an impedance tube at a frequency range of 250 – 3000 Hz. The volume fraction of pineapple leaf fibers, paper waste, and resin epoxy concentrations were 20% : 30% : 50%, 25% : 25% : 50%, and 30% : 20% : 50%. The thickness for the sound absorption coefficient was 2 cm and 3 cm, while the thickness of the impact strength was 0.5 cm. The highest sound absorption coefficient of pineapple leaf fibers composite for 30% : 20% : 50% volume fraction was 0.788 for sample 2 cm. The highest impact strength for 20% : 30% : 50% volume fraction of the thickness of 0.5 cm was 3.527 J/mm2. The results of the sound absorption coefficient will increase if used more pineapple leaf fibers but it will decrease the impact strength. Based on this research, the pineapple leaf fibers will improve the quality of the composite that can be used as a sound-absorbing material as well. These materials possess the promising potential to decrease waste and are used in industries for a low cost.

Due to accelerated modernization, urban environmental waste is being generated at an exponential rate, and paper is one of the largest solid wastes. Among them, digital printing waste paper has remarkable fiber quality and purity, making it a superior renewable fiber resource. However, the printing method and ink/toner used in the digital printing process are different from traditional printing methods, and the waste paper is relatively difficult to deink, resulting in the traditional waste paper utilization industry (recycled paper) is not given much attention and becomes low-value waste paper. How to realize the resourcefulness and high-value and efficient utilization of digital printing waste paper fiber (DPWF) is a real problem that needs attention in the field of renewable resources. In this paper, DPWF was used in the field of melt blending filled thermoplastic resin composites to avoid the waste paper deinking process while improving various properties of the material. It is shown that the best mechanical properties of the composites are achieved at 35% DPWF content. At the same time, coupling agent was used to further improve the properties of the composites in response to the interfacial incompatibility between fiber and resin. The best modification effect was achieved when the coupling agent was added at 3%, at which time the interfacial, water absorption, crystallization and thermal properties of the composites were improved, among which vinyltrimethoxysilane (A171) and γ-methacryloxypropyltrimethoxysilane (KH570) had significant effects.

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]

Purpose: The purpose of this study is to reveal the usability of waste paper sludge on the production of composite materials and the printability of their surfaces were investigated. Design/methodology/approach: First, composite plates were produced by using dried and milled waste sludge together with polyester resin and epoxy. Screen printing using water, solvent and UV-based inks were carried out. Findings: It was determined that UV and solvent-based inks in both resin groups were permanently attached to the surface of composite plates produced using paper mill waste sludge, while it was found that the adhesion was not achieved sufficiently in cardboard factory waste sludge. Originality/value: The unique aspect of this study is obtained the composite plates from paper mill and cardboard mill waste sludge and improved the printability of them. [ABSTRACT FROM AUTHOR]

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.

Fiber-gypsum board is a composite material, in which fiber is used as the reinforcement in the matrix of gypsum. The purpose of this research was to investigate the effect of adding different amounts of waste paper fibers on the strength, and the fracture behavior of fiber-gypsum board. For this purpose, zero, 5, 10, 15, 20, 25 and 35 percent gypsum was substituted by waste paper fibers in the mixture. The results of bending strength, internal bonding and moisture absorption after one month exposure to 100% relative humidity measurement showed that increasing the percentage of fibers up to 20% increased the mechanical properties. In general, using twenty percent fibers in the mixture increased the bending strength by 50% and the internal bonding was increase two and half times compared to the control samples. The load-displacement curve shows that the dosage of 5 to 15 percent of fibers does not change the fracture behavior of the fibergypsum board and exhibited brittle fracture as in control samples. While at higher dosage, the flexibility increases and the failure becomes ductile. Therefore, the best conditions in terms of strength, resistance, and flexibility was reached at 20% substitution of gypsum with waste paper fibers. [ABSTRACT FROM AUTHOR]

Due to the increasing accumulation of wastes around the world, the demand for sustainable products is increasing. Paper is a commonly disposed of material that can pose problems even when it is recycled. The concept of using cardboard (CB) as a material for furniture production has been around for many years, but CB furniture does not last long. This study examined the feasibility of using post-consumer recycled paper to produce paper-based boards for furniture design. Cardboard (CB) and office paper (OP) were the main post-consumer materials that were used. The CB and OP were mixed with polylactic acid (PLA) and limestone. The boards were made at a temperature of 200 °C and pressed at a pressure of 3.5 N/mm2 using a single opening hydraulic press. The physical and mechanical properties were tested according to the European standards for woodbased panels. Tests that are critical for furniture parts, such as the modulus of rupture (MOR), the modulus of elasticity (MOE), the internal bond, the screw withdrawal resistance, the thickness swelling, and the water absorption were examined. The paperboard samples exceeded some of the requirements for the general use of boards for interior fitments (including furniture) for use in dry conditions (Type P2) and for non-load bearing boards for use in humid conditions (Type P3). [ABSTRACT FROM AUTHOR]

The potential utilization of melamine impregnated paper (MIP) waste in thermoplastic composites was investigated. Composites were also manufactured utilizing wood flour (WF) at the same filler rates for comparison. The composites were manufactured using a compression molding method. The effects of filler type and filler rate on the mechanical properties of low-density polyethylene (LDPE)-based composites were evaluated. Mechanical properties, such as tensile and flexural strengths, were determined in accordance with ASTM D638 (2001) and ASTM D790 (2003), respectively. Results showed that filler type and filler content had significant effects on all mechanical properties investigated. Both fillers improved all mechanical properties except for tensile strength and elongation at break of LDPE. In conclusion, MIP waste has a potential to be utilized in thermoplastic-based composite manufacturing and might generate some economic and environmental benefits. [ABSTRACT FROM AUTHOR]

In this study, the reinforcing effect of recycled newsprint paper (RNP) in cement boards has been investigated. The experiment was designed to apply two variable factors, RNP and calcium chloride (CaCl2). Cement-fiber boards with the density of 0.7 kg/m3 were manufactured using fiber/cement ratios of 10:90, 15:85, 20:80 and 25:75 (w/w) and 3% and 5% CaCl2 as accelerator. Minimum four boards (replications) were fabricated for each combination of variables, and the mechanical and physical properties of the boards were evaluated. The statistical analysis showed that the effect of the RNP and CaCl2 contents on modulus of rupture of cement fiber boards were significant at 1% significant level. The results showed that addition of CaCl2 enhanced the mechanical properties of the boards. All properties of the boards were improved as the CaCl2 content was increased from 3% to 5%. The modulus of rupture and modulus of elasticity of the boards decreased with addition of RNP, and the maximum values were obtained at RNP loading of 10%. The results also showed that as the fiber content was increased, significant increase in water absorption and thickness swelling occurred. Increasing RNP fiber content from 10% to 25% reduced both the mechanical and physical properties considerably. The optimum condition was obtained when the RNP and CaCl2 contents were 10% and 5%, respectively.

Responsiveness was given to the effects of cassava starch and natural rubber as binders on the flexural strength and the water absorptivity properties of the developed rattan particulate reinforced paper pulp based composites. Paper pulp was produced by chopping waste papers into smaller pieces and soaked in boiled water after which it was stirred thoroughly to form paper pulp. Rattan particulate was produced by hammering, chopping, pounding and milling of rattan canes followed by sieving into a particle size of 437 µ. Varying mass of paper from 300-400 g and particulate rattan in treated and untreated form of 2-8 g were mixed and bonded with natural rubber and cassava starch, respectively for the various samples developed. The mixtures were thoroughly mixed to produce homogenous pastes and poured into 150 x 50 x 30 mm detachable mould and compacted for 5 minutes using a laboratory compaction machine maintained at 20 KN. The developed composites were allowed to cure at room temperature for 27 days after which flexural and water absorptivity tests were carried out on the samples. It was noticed that the composite samples ST4 and S5 containing cassava starch happen to be the best in terms of flexural strength while NR2 gave the best water- repellent outcome.

In this investigation, tensile and physical properties of polypropylene (as matrix)/wheat straw fiber/paper mill sludge (as filler) composites was studied. The ratio of wheat straw fiber/ paper mill sludge was selected as 40/0, 30/10, 20/20, 10/30 and 0/40 (w/w) were used. Also, for better compatibility between the two phases 3% MAPP as coupling agent was used. Mixing process was done in twin screw internal mixer extruder, and then composite samples were manufactured by injection molding. Result indicated that the tensile modulus of elasticity improved with increasing fillers and also it was observed that the toughness of composite increased when compared to the pure PP, while due to the usage of more paper sludge, these properties was improved. Tensile strength of composite decreased with adding 40% wheat straw fiber, but with addition of sludge tensile strength increased significantly. Adding wheat straw in PP matrix and its hydrophilic properties resulted in the highest rates of water absorption and thickness swelling. However, adding paper sludge and lower amount of lignocellulosic material, and the compatibilizer noticeably decreased the physical properties due to better bonding between two phases.

Composite production of polypropylene polymers was considered in this work as the matrix, filled with the fiber of wheat straw and paper mill sludge; different ratios were evaluated relative to their potential as reinforcement materials. Maleic anhydride polypropylene (MAAP) was used at 3% by weight. The bending modulus of elasticity of the composites significantly increased with both types of filler. The highest bending modulus of the composites was found with 40% of paper mill sludge. Using 40% wheat straw fiber decreased bending strength, but the addition of paper mill sludge increased bending strength. The highest bending strength of the composites related to polypropylene/10% of wheat straw fiber and 30% of paper mill sludge. In terms of impact strength, the use of paper mill sludge had a higher impact on strength than wheat straw fiber composites. The inclusion of MAPP improved the mechanical properties of all composites. Scanning electron micrographs showed that the composite paper mill sludge improved the adhesion and dispersion of the filler (paper mill sludge/fiber paper instead of wheat) in the matrix.

Regarding its geographical location, West Sumatra is an area prone to earthquakes. The solution to this condition is by mitigating the effects through the construction of earthquake-resistant buildings. Earthquake-resistant buildings may be constructed by replacing polymeric materials with characteristics of light, durable and good flexibilities. One of which by replacing stone as common building structure with composite material. Composite wall panels that are expected to be utilized to construct a resistant building, are made by mixing polypropylene plastic waste with coconut fiber and primary sludge from paper mill waste. The mixing method was performed using an extruder (dry mixing with heat). Composition of coconut fiber, primary sludge, and paper mill waste were 20:20:60, respectively based on the previous study. Method for casting composite wall panels was performed using hot-press. The composite wall panels showed a flexural properties of 9.6 N/mm², modulus of elasticity of 2,640 N/mm², melt temperature at 161.21°C, combustion point at 463.55oC, decomposition point at 476.99°C, carbon residue of 15.1%, density of 1.093 g/cm³, thickness swelling of 0.104%, internal bond strength of 0.61 N/mm², a good morphochemical interaction and following EN 634-2-2007 standard. [ABSTRACT FROM AUTHOR]

Due to accelerated modernization, urban environmental waste is being generated at an exponential rate, and paper is one of the largest solid wastes. Among them, digital printing waste paper has remarkable fiber quality and purity, making it a superior renewable fiber resource. However, the printing method and ink/toner used in the digital printing process are different from traditional printing methods, and the waste paper is relatively difficult to deink, resulting in the traditional waste paper utilization industry (recycled paper) is not given much attention and becomes low-value waste paper. How to realize the resourcefulness and high-value and efficient utilization of digital printing waste paper fiber (DPWF) is a real problem that needs attention in the field of renewable resources. In this paper, DPWF was used in the field of melt blending filled thermoplastic resin composites to avoid the waste paper deinking process while improving various properties of the material. It is shown that the best mechanical properties of the composites are achieved at 35% DPWF content. At the same time, coupling agent was used to further improve the properties of the composites in response to the interfacial incompatibility between fiber and resin. The best modification effect was achieved when the coupling agent was added at 3%, at which time the interfacial, water absorption, crystallization and thermal properties of the composites were improved, among which vinyltrimethoxysilane (A171) and γ-methacryloxypropyltrimethoxysilane (KH570) had significant effects. • DPWF is an excellent quality recyclable fiber resource, with 35% being its optimal content when used as a reinforcement. • Three structurally similar modifiers were used for the improvement of interfacial boundaries and 3% was the optimum content. • The kinetics of water absorption and thermal decomposition of the composites were investigated. [ABSTRACT FROM AUTHOR]

In this study two types of paper sludge, prepared by Mazandaran wood and paper company and Latif papermaking company along with wood flour utilized as plastic filler in polypropylene and high density polyethylene based composites. Weight percentage ratio of coupling agent, polymer and filler were kept constant 2%, 38%, and 60% in all formulations, respectively and composites were prepared by varied ratios of paper sludge and wood flour include 0: 60, 40: 20, 20: 40, and 60:0. Density, water absorption and thickness swelling of injection molded composites then measured. The results indicated the gradual substitution of wood flour by paper sludge increases the density of composites, and improves their water absorption and thickness swelling. The ratio of paper sludge to wood flour had statistically significant difference on all these properties, but the paper sludge type showed statistical difference just on the density of composites. Further to that, polypropylene based composites demonstrated lower density, water absorption and thickness swelling compared to high density polyethylene based ones.

Composite films were studied as possible candidates for the central or support layer of synthetic paper in a multilayer structure. Recycled post-consumer polypropylene films were reinforced with inorganic fillers at various compositions and under several processing conditions, with the aim of optimizing the physical and mechanical properties of rigidity and low density. Three types of CaCO3, with and without surface treatment of the particles, were used, but only the treated ones were suitable for use in paper films. These samples were then used to analyze possible correlations of properties with composition and processing conditions, varying the CaCO3 particle size distribution and the film processing method, from casting extrusion (flat die) to blown-film extrusion (tubular die). An increase in film stiffness was observed as a function of CaCO3 content and a concentration of 30% CaCO3 was found to be best for the specific application. The flat films were stiffer than the tubular ones. The densities of all the composite films were considered high, compared to a pulp-based paper and a commercial synthetic paper. No significant effect on the physical-mechanical properties analyzed was observed when the CaCO3 particle size distribution was varied. Microcavities were found to form at the surface of flat films submitted to a bi-orientation process performed at laboratory scale; no other sample showed this surface morphology.

This research was carried out to produce a rattan particulate reinforced paper pulp based composite with satisfactory flexural and water absorptivity that can serve in applications such as household ceiling and partitioning board. Paper pulp was produced by chopping waste papers into smaller piece and soaked in boiled water after which it was stirred thoroughly to form paper pulp. Rattan particulate was also produced by beating, chopping and milling of rattan canes. The rattan particles were sieved from where particle size of 437 u was used. Varying mass of paper from 300-400 g and particulate rattan in treated and untreated form within the range of 2-8 g were mixed and bonded with natural rubber that serves as binders for the various samples produced. The mixtures were thoroughly mixed and poured into 150x50x30mm detachable mould and compacted for 5 minutes using a laboratory compaction machine. The composite were allowed cure at room temperature for 21 days after which flexural and water absorptivity tests were carried out on the samples. It was found that the composite samples denoted as NRT4 and NR5 happen to be the best in terms of flexural strength properties while the addition of rattan particulate fiber aid water repellent potential for the developed composites. [ABSTRACT FROM AUTHOR]

Fly ash-based calcium silicate (FACS), which has a large surface area (121 m2/g) and porous structure, has the potential to be used as a filler for the production of high-bulk paper. In theory, paper with a higher bulk has a lower strength. This work explores the possibility of improving paper strength without compromising its bulk through co-flocculation of cellulosic fines and FACS. To investigate the effect of co-flocculation on paper properties, composites made with various ratios of fines to FACS were studied. Results showed that paper bulk and tensile strength increased with increasing ratio of fines to FACS, up to 0.3 at 17% filler content. To further confirm these findings, the structures of composites were studied with a light microscope and scanning electronic microscope (SEM). Images showed that the composite formed at the ratio of 0.3 exhibited a larger size and looser structure than other composites, which can be attributed to the improvement of the paper’s strength and bulk. Schemes for the composite formation process and its interactions with fibers were also proposed.

Traditional wood-based panels composed of wood and petroleum based adhesives is widely used in furniture manufacturing and construction industries. However, these adhesives are not biodegradable, inhibiting the recycling of artificial board. More seriously, the emission of carcinogenic formaldehyde will lead to severe pollution and environmental issues. This study presents a method for preparing self-bonding composites. Waste poplar powder is used as raw material in the biocomposite, in which exogenous lignin is added, and lignin is extracted from the waste of the paper industry - black liquor, which is beneficial to the environment and the recycling of resources. The resulting biocomposites are characterized by aldehyde-free, better strength, and water stability. The dimensional stability and mechanical strength, bending strength (84.40 MPa), and tensile strength (35.40 MPa) of the biocomposite are 2.0 and 1.6 times that of composites obtained by hot pressing without pretreatment and are 2.7 and 2.4 times that of medium density fiberboard (MDF), lignin plays an important role as an adhesive, which is the key to improving mechanical properties. Moreover, the biocomposite features higher water stability and fire resistance than the traditional wood fiberboard. In conclusion, the developed black liquor-wood biocomposites are potential alternatives used to replace the formaldehyde wood-based fiberboard. [Display omitted] • An aldehyde-free wood-based panel was prepared by a resource-saving method. • The flexural and tensile strengths are 84.40 MPa and 35.40 MPa. [ABSTRACT FROM AUTHOR]

Composite production of polypropylene polymers was considered in this work as the matrix, filled with the fiber of wheat straw and paper mill sludge; different ratios were evaluated relative to their potential as reinforcement materials. Maleic anhydride polypropylene (MAAP) was used at 3% by weight. The bending modulus of elasticity of the composites significantly increased with both types of filler. The highest bending modulus of the composites was found with 40% of paper mill sludge. Using 40% wheat straw fiber decreased bending strength, but the addition of paper mill sludge increased bending strength. The highest bending strength of the composites related to polypropylene/10% of wheat straw fiber and 30% of paper mill sludge. In terms of impact strength, the use of paper mill sludge had a higher impact on strength than wheat straw fiber composites. The inclusion of MAPP improved the mechanical properties of all composites. Scanning electron micrographs showed that the composite paper mill sludge improved the adhesion and dispersion of the filler (paper mill sludge/fiber paper instead of wheat) in the matrix. [ABSTRACT FROM AUTHOR]

An approach is demonstrated for the manufacturing of a microfibrillated cellulose (MFC) composite paper. A key element in the manufacturing paradigm is the use of high consistency suspensions to improve retention and minimize the need for water removal after forming. The rheological characterization of the composite furnish, which contained 70% structured pigment, 20% MFC, and 10% pulp fibers, revealed a gel-like shear thinning behavior of the suspension, which differs greatly from traditional fiber-based papermaking furnishes. The results from laboratory and pilot scale studies show that the headbox consistency range from 5 to 10% offers the best combination of processing, forming characteristics, retention, and dewatering. While the furnish dewatering in laboratory scale was very problematic, under suitable dynamic conditions the wire section dewatering was excellent. The results of this study suggest that the MFC composite can be manufactured on a modified paper machine and that the final product will have an attractive cost structure.

Polyaniline/filter-paper (PANI/FP) composite was prepared by in-situ polymerization of polyaniline onto filterpaper and subsequently evaluated for the removal of Coomassie brilliant blue (CBB) from aqueous solution. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier-transform infrared (FTIR) spectroscopy were used to investigate the morphology and physicochemical properties of PANI/FP composite. Batch experimental results showed that the pH value and temperature could affect the removal capability of the PANI/FP composite. Langmuir and Freundlich models were used to analyse the equilibrium adsorption. Pseudo-first and pseudo-second order models were used to investigate the kinetics of CBB adsorption onto PANI/FP composite. [ABSTRACT FROM AUTHOR]

In the present work, unshredded waste newspaper based composites have been prepared in polyester resin matrix. Reinforcing material, waste newspaper is characterized by chemically, X-ray diffraction (XRD) methods, Fourier transform infrared spectroscopy (FTIR) and tensile properties. Three different fibre content composite samples, namely 25%, 34%, and 50% (by weight) are prepared by hand lay-up techniques. Water absorption and thickness swelling tests are conducted by immersing composite samples in distilled water at room temperature. It is found that the percentage of moisture uptake and thickness swelling are increased as the fibre volume fraction is increased due to the high cellulose content. The tensile, flexural and interlaminar shear strength properties of water immersed samples are investigated and compared with dry composite samples. It is observed that after swelling the mechanical properties of composites are found to decrease with increase in percentage moisture uptake. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with a new application of polyaniline (PAn) and polypyrrole (PPy) synthesized chemically. Coated on sawdust via cast method the polypyrrole/sawdust (PPy/SD) and polyaniline/sawdust (PAn/SD) were used as effective adsorbents for the removal of heavy metals, anions, color and COD (chemical oxygen demand) from mill paper wastewater. The products were investigated in terms of morphology and chemical structure using scanning electron microscopy and Fourier-transform infrared spectroscopy (FTIR), respectively. It was found that PPy/SD and PAn/SD are very simple to prepare and can be used as effective adsorbents in the removal of anions, heavy metals, color and COD from paper mill wastewater. [Copyright &y& Elsevier]

Rational compositions of a polymer composite material are proposed and technological prerequisites for manufacturing technical products for chemical engineering, based on liquid resol phenol–formaldehyde resins and dispersed fibrous filler manufactured by mechanical processing of the organic waste from fiber production in the pulp and paper industry are evaluated. Methods and parameters of technological stages, including the preparation of raw materials and their mixtures, production of a polymer dispersed filled press material, and hot molding (pressing) products, were determined and tested. Recommendations are given on the hardware and process design of the technological stages of the production of a quality polymer composite material and improvement of its properties. The regularities of changes in the physical and mechanical properties (response on compression, tension, and bending, as well as impact strength and moisture and oil absorption) of the composites with the concentration of dispersed fibrous filler at the recommended thermal pressing parameters (temperature 170 °C, specific pressure 20 MPa, exposure time 1 min/ 1 mm product thickness). Clear evidence is provided showing that the upper limit of the percentage of dispersed fibrous filler in the studied phenolic samples is 40-60%, and at higher percentages the mechanical parameters are strongly deteriorated and the moisture and oil absorptions become much higher than the limits permitted by standards for technical phenolic plastics. The results of the study make it possible to recommend the compositions based on liquid resol phenol–formaldehyde resins and modified fibrous waste from the pulp and paper industry and the hardware and process design for the production of phenolic products of chemical engineering. The developed composites allow homogeneous coloring in various colors (except for white) and imparting to their surface a smooth shiny texture. [ABSTRACT FROM AUTHOR]

We report an innovative sensor for the determination of low levels of total cholesterol (TC) in saliva. The sensor consists of an enzyme-loaded nitrocellulose (NC) paper and an impedimetric sensor based on hybrid material derived from Pt black/PEDOT:PSS (BPt/PEDOT) and Pt black/Nafion (BPt/Nafion) composite. The enzyme-loaded NC paper combined impedimetric sensor with the BPt/Nafion composite was able to detect TC values in the range of 5–4000 ng/ml with a normalized sensitivity (impedance change) of 7.5%/decade at 1 kHz and 0.99 linear correlation. In order to detect cholesterol in saliva reliably, the detection limit should be lower than the clinical level in saliva (5–46 μg/ml). The fabricated sensor had a detection limit that was sufficiently low and it had a wide detection range. In addition, the impedimetric sensor with BPt/Nafion composite exhibited more reproducible and cholesterol-selective normalized impedance changes than the sensor with the BPt, BPt/PEDOT electrode. In the human serum and saliva test, the impedance change from diluted serum and saliva concentration was compared. The impedimetric sensor exhibited relatively well matched correlation between diluted serum and standard TC. And TC concentration in saliva was at least 10 −3 less than the concentration in the serum. [ABSTRACT FROM AUTHOR]

Lignocellulosic material used as raw material in pulp and paper production due to major chemical alterations produce different waste compounds and composite manufacturing is an area providing the opportunity to utilize such wastes. In order to investigate the feasibility of using papermaking sludge in composite production, four combinations of wood flour/ papermaking sludge/ high density polyethylene ratio were formulated, then composite panels were made and the physical properties of manufactured panels were evaluated. The content of maleated polyethylene (MAPE) and the polymer was constant 2% and 38% respectively, for all formulations. The results indicated that long term water absorption in particular thickness swelling decreased with increasing sludge content. Furthermore, moisture diffusion coefficient of samples containing 30% sludge and 30% wood flour was more than others. The results revealed that using papermaking sludge can be an alternative option for lignocellulosic raw material.

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

The present study investigated the use of algae biorefinery waste and wastepaper in the preparation of cost-effective and eco-friendly xerogels for the removal of congo red (CR) and Fe2+. The xerogel properties such as density, swelling degree and porosity were modified by incorporating alginate extracted from the brown seaweed Cystoseira trinodis. The developed biosorbents exhibited a light and porous network structure and were characterized by a fast uptake of CR and Fe2+ and adsorption efficiency was increased at pH 6–8. The equilibrium adsorption capacity was found to be 6.20–7.28 mg CR g−1 biosorbent and 8.08–8.39 mg Fe2+ g−1 biosorbent using different xerogels. The adsorption of CR obeyed first-order kinetics, while, Fe2+ followed second-order kinetics. Intraparticle diffusion model suggested a boundary layer effect. The adsorption capacity was maximally obtained as 41.15 mg g−1 and 169.49 mg g−1 for CR and Fe2+ using wastepaper/ Spirulina and wastepaper/alginate/ Spirulina xerogel, respectively. Temkin isotherm fitted better to the equilibrium data of CR adsorption than Langmuir and Freundlich models. While, equilibrium data of Fe2+ exhibited a best fit to both Langmuir and Freundlich models. Additionally, the Dubinin-Radushkevich isotherm suggested that adsorption mechanism of CR or Fe2+ is predominately physisorption. Investigation of thermodynamic parameters such as ΔH° and ΔS° and ΔG° confirmed the feasibility, spontaneity, randomness and endothermic nature of the adsorption process. Electrostatic attraction, H-bonding and n-π interactions were mainly involved in the biosorption process of CR. The results of this study showed that the developed xerogels could be effectively applied for dye and heavy metal removal at low concentrations. Image 1 • Algal biorefinery and paper wastes were utilized for the development of xerogels. • Xerogels effectively adsorbed congo red and Fe (II) from aqueous solution. • Incorporation of alginate into xerogels affected their physico-chemical properties. • The adsorption mechanism was predominately physisorption. • Temkin isotherm well suited CR adsorption, while Langmuir and Freundlich best fitted Fe adsorption. [ABSTRACT FROM AUTHOR]

Background: Until now, environmental sustainability issues are almost entirely unsolved for packaging materials. With the final aim of finding materials with a single recycling channel, cellulose fiber/poly(vinyl)alcohol composites were investigated. Methods: After extrusion and injection molding, samples of composite with different cellulose fiber content (30%, 50% and 70% w/w) were tested. Results: Tensile mechanical tests exhibited an improvement in composite stiffness when the reinforcement content was increased together with a decrease in composite elongation. Solubility tests performed at room temperature and 45°C showed different behavior depending on the water-resistant film applied on the composite (50% cellulose fiber content). In particular, the uncoated composite showed complete solubility after 2 hours, whereas at the same time point, no solubility occurred when a non-water-soluble varnish was used. Conclusions: The proposed composites, named Poly-paper, appear to warrant further investigation as highly sustainable packaging. [ABSTRACT FROM AUTHOR]

We report a novel biodegradable piezoelectric composite fabricated from paper and the piezoelectric salt, sodium potassium tartrate tetrahydrate (Rochelle salt, which we term PiezoSalt). The piezoelectric composite is non-toxic and is fabricated free of environmentally harmful solvents by impregnating PiezoSalt into a paper matrix through the crystallization of a concentrated PiezoSalt brine solution. The composite exhibits an effective piezoelectric constant between 3 and 25 pC N −1 , dielectric constant of 7, mass density of 625 kg m −3 , and a Young’s modulus between 7 and 8 GPa. When directly actuated, cm-scale cantilevers consisting of PiezoSalt paper produced clearly audible sound waves, illustrating one potential application. PiezoSalt paper composite provides a scalable, high throughput approach for biodegradable sensors and transducers with unsurpassed environmentally friendly processing. [ABSTRACT FROM AUTHOR]