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Effects of cellulose nanofibers (CNF) and cationic starch (CS) were evaluated as coating components relative to the physical and mechanical properties of fluting papersheets fabricated from recycled corrugated cardboard fibers. Fabricated fluting papers were subjected to size press applications by three different coating blends. Coating suspensions were prepared at various concentrations of CNF (0.5%, 1%, 2%, 3%, and 4%) and 4 wt% CS, and the same amounts of CS/CNF. The paper sheets were fabricated using size press machine as three-time repetitive applications, followed by one-time drying section, and compared to uncoated, CScoated, and CNF-coated papers. The application of CNF suspensions increased tensile indices up to 11.7%. Moreover, CS/CNF suspensions resulted in a 67.2% increase in tensile index values. The coating of CS/CNF suspensions increased the burst index values by 163% at the CS+1%CNF concentration when compared to the control pulp. Surface application of prepared suspensions reduced the porosity of the samples under all conditions. The highest reduction in the air permeability was observed in the CS+4%CNF-coated samples as 91.5%. It can be concluded that the superficial applications of CNF on the physical and mechanical properties of recycled fluting paper was more effective in the presence of CS. [ABSTRACT FROM AUTHOR]

In this study, a comparative analysis of silver nanoparticles treatment and chitosan coating on packaging paper barrier properties was carried out. In order to examine the water, grease, and antibacterial barrier properties of silver nanoparticle-treated and chitosan-coated laboratory-obtained paper samples, a mixture of bleached softwood and hardwood celluloses was used. In order to conduct the comparative analysis SEM, water contact angle, Cobb60, and Kit tests were carried out on a cellulose sample, and four paper samples (three of them treated with silver nanoparticles—1, 2, and 3 mL/20 cm2 or chitosan coated—0.5, 1, and 2 g/m2) together with the inhibition activity against nine Gram-positive and Gram-negative bacteria, yeast, and fungal strains. The study found out that increasing the silver nanoparticle treatment and chitosan coating led to improved water resistance, while grease resistance was improved only for chitosan coated paper samples. Additionally, paper treated with 3 mL/20 cm2 of silver nanoparticles had the highest antibacterial protection (81.6%) against the Gram-positive bacterium Staphylococcus aureus, followed by Gram-negative Escherichia coli (75.8%). For the rest of the studied microorganisms, the average efficiency of the treated paper was 40.79%. The treatment of the paper with 1 and 2 mL/20 cm2 of silver nanoparticles was less effective—27.13 and 39.83%, respectively. The antibacterial protection of 2 g/m2 chitosan-coated paper samples was the most effective (average 79%) against the tested bacterial, yeast, and fungal strains. At 1 and 0.5 g/m2 chitosan coatings, the efficiency was 72.38% and 54.67%, respectively. Gram-positive bacteria, yeasts, and fungal strains were more sensitive to chitosan supplementation. [ABSTRACT FROM AUTHOR]

In the present study, an environmentally friendly oil- and water-resistant paper was developed using a holo-lignocellulosic nanofibril (LCNF)-based composite coating. The LCNF was prepared from wheat straw using a biomechanical method. Characterizations of oil- and water-resistant coated paper and the effect of LCNF content on the performance of the coated paper were confirmed by combining contact angle analysis, Cobb 300s, and mechanical performance tests. The results show that the barrier performance and mechanical strength of the coated paper were greatly improved with the increase of LCNF content. The contact angle of oil and water of coated paper containing 50% LCNF were 69° and 78°, respectively, while the contact angle of oil and water of the base paper were only 30° and 20°, respectively. Cobb 300s values reduced from 110 g/m2 to 30 g/m2 when the LCNF content increased from 50% to 90%. Moreover, under the coating amount of 20 g/m2, the tensile strength of the coating paper was 0.980 KN/m, an increase of 10.11% compared with the base paper. The bursting strength reached 701.930 KPa, which was 10.75% higher than the base paper. In short, it is feasible to prepare LCNF from wheat straw, and apply it to produce water-proof and oil-proof paper. The water-proof and oil-proof paper developed in this study not only offers a novel approach to addressing white pollution but also presents a new research avenue for exploring the potential applications of agricultural waste. [ABSTRACT FROM AUTHOR]

The vast amount of synthetic polymers used in packaging is putting a strain on the environment and is depleting finite, non-renewable raw materials. Abundantly available biopolymers such as alginate, chitosan and microfibrillated cellulose (MFC) have frequently been suggested in the literature to replace synthetic polymers and their barrier properties have been investigated in detail. Many studies aim to improve the properties of standalone biopolymer films. Some studies apply these biopolymers as barrier coatings on paper, but the solids content in most of these studies is quite low, which in turn would result in a high energy demand in industrial drying processes. The aim of this study is to suggest a laboratory procedure to investigate the suitability of these biopolymers at higher and such more industrially relevant solids content as potential coating materials for paper and board in order to improve their barrier properties. First, biopolymer solutions are prepared at a high solids content at which the viscosity at industrially relevant higher shear rates of 50,000 s−1 (1000 s−1 for MFC) is in the same range as a synthetic reference material (in this case ethylene vinyl alcohol EVOH) at 10 wt%. These solutions are analyzed regarding properties such as rheology and surface tension that are relevant for their coatability in industrial coating processes. Then, free-standing films are cast, and the films are characterized regarding important properties for packaging applications such as different surface, mechanical and barrier properties. Based on these results suitable biopolymers for future coating trials can be easily identified. [ABSTRACT FROM AUTHOR]

In this study, rose oil was encapsulated with stearic acid substituted polyvinyl alcohol macromolecule. In the first part of the study, stearic acid substituted polyvinyl alcohol macromolecule was synthesized and its chemical structure was elucidated by ATR-FTIR and ¹HNMR. Then, rose oil was encapsulated using this obtained polymer. The chemical structure of the obtained capsules was made by ATR-FTIR, and dimensional analysis was done by scanning electron microscope (SEM). After the obtained capsules, a paper coating formula was prepared and coated on 80 g/m² paper. The resulting scented papers were printed using the screen printing technique. The color, gloss, and deformation of the capsules on the surface of the printed and unprinted papers were determined by spectrophotometer, glossmeter and SEM. As a result, it was determined that the synthesized polymer could encapsulate the rose oil and the papers using these capsules could be printed without deformation. [ABSTRACT FROM AUTHOR]

Bio-based polymer composites find increasing research and industrial interest in different areas of our life. In this study, cellulose nanofibers (CNFs) isolated from sugar beet pulp and nanoemulsion prepared from sugar beet pectin and pomegranate extract (PGE) were used for making films and used as coating with antioxidant and antimicrobial activities for paper. For Pectin/PGE nanoemulsion preparation, different ratios of PGE were mixed with pectin using ultrasonic treatment; the antibacterial properties were evaluated to choose the formula with the adequate antibacterial activity. The antioxidant activity of the nanoemulsion with the highest antimicrobial activity was also evaluated. The nanoemulsion with the optimum antibacterial activity was mixed with different ratios of CNFs. Mechanical, greaseproof, antioxidant activity, and antibacterial properties of the CNFs/Pectin/PGE films were evaluated. Finally, the CNFs/Pectin/PGE formulation with the highest antibacterial activity was tested as a coating material for paper. Mechanical, greaseproof, and air porosity properties, as well as water vapor permeability and migration of the coated layer from paper sheets in different media were evaluated. The results showed promising applicability of the CNFs/Pectin/PGE as films and coating material with antibacterial and antioxidant activities, as well as good stability for packaging aqueous, fatty, and acidic food products. [ABSTRACT FROM AUTHOR]

Biodegradable paper cups coated with rice bran wax and whey protein isolate were designed to package popcorn. Coatings with different concentrations of whey protein isolate (5.5, 7.75, and 10% w/v) and rice bran wax (0.2, 0.4, and 0.6% w/v) were applied on the outer surface of the paper cups. Thickness, color changes, Young's modulus and tensile strength, water vapor transmission rate (WVTR) of the coated and uncoated cups, and also popcorns properties (pH, texture, and sensory properties) were evaluated. Water vapor transmission rate, Young's modulus, thickness, total color change index, and tensile strength of coated cups with the optimal coating formulation was 19.785 (g/m2 day), 11.810 (MPa), 276.583 (µm), 1.839, and 11.222 (MPa), respectively. The results showed that paper cup coating increased thickness and yellowness and reduced the brightness, Young's modulus, and WVTR. Coating had a positive effect on the pH and texture of popcorns packaged in coated cups than samples packed in uncoated cups (p <.05). With increasing storage time due to moisture absorption, popcorn changes from crisp to viscoelastic and increases tissue firmness (p <.05). Popcorns' taste in uncoated cups had gained significantly lower scores by panelists compared with the samples packed in coated cups. There was a significant decrease in the general acceptance of popcorn during storage and also the type of coating used in the packaging cup (p <.05). Storage time and type of coating showed no significant effect on the moisture content, odor, and appearance of popcorn. In sensory evaluation, the coated packaging increased the taste, no difference in odor and appearance, and increased the overall acceptance of popcorn compared to the sample in uncoated cups. In general, the results showed that paper cup coating could be a new approach for barrier property improvement in paper‐based food packaging and extending the shelf life of the products. [ABSTRACT FROM AUTHOR]

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

The high demand for flexible electroconductive elements, such as organic coatings, is associated with the development of IoT devices, wearable health monitoring devices, and similar devices. To meet cost and environmental standards, the ideal coating should use the richness of nature, be biodegradable, and be water soluble to avoid the use of harmful organic solvents. All of these criteria are met by the composite coating consisting of sodium lignosulfonate (SLS) and multiwall carbon nanotubes (MWCNTs). Furthermore, the SLS/CNT coating on paper substrates is highly electroconductive, hydrophobic, and resistant to annealing, high humidity, bending, and scratching. The electrical conductivity of the SLS/CNT coating varies depending on the substrate used, but it is highly conductive and resistant on all substrates tested. Most importantly, due to the use of abundant and mass produced and cheap materials, the price of a coating containing 77 wt% SLS and 23 wt% CNT, with a sheet resistance of 113 Ω/sq is estimated to be around 2.05 EUR/m2. This coating can be especially beneficial for large-scale applications, such as heating films. [Display omitted] • SLS is an affordable and readily available stabilizer for CNT dispersion in water. • SLS/CNT creates a highly conductive coating on cellulose substrates. • The SLS/CNT coating on paper has potential applications as cost-effective sensors or heaters. • The conductivity of the coating is influenced by the properties of the substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] • A groundbreaking approach was proposed to produce phosphorylated cellulosic paper. • Cellulose phosphorylation by thermo-compression induces a hornification phenomenon. • Hornification increases the paper crystallinity (91%) and thus the overall quality. • Coating the papers with EVA polymer strongly increase their specific properties. • The new phosphorylation approach produced an effective paper for packaging. With the increasing demand for environmentally friendly alternatives to traditional plastic packaging, the development of sustainable cellulosic-based materials has become a strategic research topic. In this concept, a groundbreaking approach was adopted herein to produce phosphorylated cellulose microfibers (CMFs)-based paper packaging via a one-pot preparation step using a thermo-compression process (150 °C under pression for 45 min) in the presence of diammonium hydrogen phosphate ((NH 4) 2 HPO 4 , denoted DAP) and urea. This process involves a chemical mechanism leading to the production of phosphorylated cellulosic paper with a very compacted structure induced by the hornification phenomenon. This phenomenon reveals the formation of additional and irreversible strong hydrogen bonds leading thus to an increase of the materials' crystallinity up to 91%, and to an enhancement of their morphological, thermal stability, flame retardancy, hydrophobicity, water vapor permeability, and mechanical strength properties. To further enhance these properties, and thus their potential applications, the as-produced phosphorylated CMF paper samples were then coated with a thin layer (40 ± 1.11 µm) of poly[ethylene-co-(vinyl acetate)] (EVA) polymer. A comparison of collected properties with those from non-phosphorylated CMFs or from materials prepared using the conventional phosphorylation process clearly demonstrates that the proposed one-pot preparation method led to the production of advanced materials more effective for packaging applications. Overall, the findings associated to this work could be used as a proof-of-concept for the development of sustainable packaging materials, which could be made by following a more efficient and cost-effective manufacturing procedure than current benchmarks. [ABSTRACT FROM AUTHOR]

Papers are raw materials with high flammability. Some of the products produced in the printing industry are used in places requiring high heat resistance. High-tech papers can be produced by adding a flame retardant to the paper coating formulation or pulp. In this study, it is aimed to prepare polyvinyl alcohol (PVA)- zinc borate / melamine / zinc borate-melamine paper coating formulations and to produce flame retardant paper by coating on paper. For this purpose, primarily zinc borate is produced by boric acid and zinc carbonate reaction. In the second part of the study, four different coating formulations were prepared by adding zinc borate, melamine and their double mixtures to the main formulation, where PVA polymer matrix was used as binder, and coatings were made on an 80g/m2 paper surface. Limiting oxygen index (LOI), gloss, color, surface energy and contact angles properties of the produced papers were determined. Offset printing was done onto coated papers with IGT C1 test printing machine. All produced flame retardant papers have good printability characteristics. [ABSTRACT FROM AUTHOR]

Nanostarch has a small particle size and large surface area compared with traditional modified starch. In this study, nanostarch was prepared by dual screw extrusion and was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and X-ray diffraction (XRD). The nanostarch was studied as a coating adhesive in surface coating of lightweight coated paper. The crystallinity of nanostarch granules was decreased by dual screw extrusion, and its average particle size was about 100 nm. The results showed that for the paper coating formula of styrene butadiene latex and an ordinary oxidized coating starch ratio of 9:5, all ordinary oxidized coating starch and part of the styrene butadiene latex can be replaced by nanostarch. When 5 parts of ordinary oxidized coating starch and 4 parts of styrene butadiene latex were replaced by 6.5 parts nanostarch, the water retention property of nanostarch coating was increased by 64.0%, and its viscosity was decreased by 11.0%. The IGT printing surface strength of lightweight coated paper by the nanostarch coating was increased by 11.6%, and the glossiness of coated paper was increased by 7.2%. These results show that nanostarch surface coatings have good prospects for application in papermaking. [ABSTRACT FROM AUTHOR]

A polyaniline/clay combination was prepared via: 1) mixing polyaniline dispersion with clay; or 2) in situ polymerization of aniline in the presence of clay. To deliver electrical conductivity to cellulosic paper, the polyaniline/clay composition was applied to the paper surface by Meyer rod coating. The conductive paper was analyzed by Scanning Electron microscopy (SEM) and Fourier Transmission Infrared spectroscopy (FTIR). For comparison purposes, conductive paper was also prepared by in situ polymerization of aniline in the presence of cellulosic fibers. The insitu formed polyaniline was deposited on the fiber surface, and the polyaniline-deposited cellulosic fibers were made into paper sheets. It was found that at the same aniline content, paper surface coating with polyaniline/clay composition gave a much higher conductivity in comparison with the use of polyaniline-deposited cellulosic fibers for paper sheet formation. [ABSTRACT FROM AUTHOR]

Hydrophobic noncrystalline porous starch (NCPS) containing microporous and amorphous structures was prepared from native corn starch via heat treatment, solvent exchange, and alkyl ketene dimer (AKD) modification. Then, antibacterial packaging was produced by combining silver nanoparticles with the hydrophobic NCPS (hydrophobic NCPS/Ag) and employing this biobased coating as a layer on the base paper. The antibacterial activity, strength, and barrier properties of the hydrophobic NCPS/Ag-coated paper were measured. In addition, the fine porous surface of NCPS, the distribution of the silver nanoparticles in hydrophobic NCPS as well as the network structure of uncoated paper and coated paper were characterized by scanning electron microscopy. Meanwhile, the hydrophobicity of the corn starch, hydrophobic NCPS, uncoated paper, and coated paper were determined using water contact angles. The silver nanoparticles had a positive effect on the antibacterial activity against Escherichia coli and Staphylococcus aureus. The air permeability, oil resistance, water vapor transmission rate, water absorption, whiteness, tensile strength, and burst strength improved compared to the uncoated paper. [ABSTRACT FROM AUTHOR]

This paper presents the results of trials to evaluate the color-stripping behaviour of offset printing colors and the effect of coating on deinking performance. Oil-based four-color inks were separately printed as base printing on coated and uncoated white poster paper, and then extensive pulping and deinking processes were carried out. Standard offset printings were conducted on paper samples using cyan, magenta, yellow, and black colors (CMYK), and the effects of deinking efficiency on the removal of each color were analysed. The pulps were made at Micro-Maelstrom Laboratory Pulper at specified conditions with and without bleaching agents. Formamidin sulfinic acid and hydrogen peroxide formulation were used as reductive and oxidative bleaching agents, respectively. Flotation deinking and thickening of pulp were practiced using Degussa flotation and thickening cell. The changes in the optical properties, such as brightness, whiteness, and color value (CIE L*, a* b*) of deinked pulp were determined. It was found that optical properties of color-stripped pulps from coated papers were better than that of uncoated office papers. However, yield was quite low in coated papers since fillers were lost during flotation process. Cyan color was found to be the most difficult one in four main color printing inks stripping out in deinking process. [ABSTRACT FROM AUTHOR]

The concept of dry surface treatment for paper coating applications has been available for more than ten years. Different from conventional coating methods such as extrusion coating and suspension coating, dry surface treatment involves a combined process of non-contact deposition of coating materials and surface smoothening of the coated paper. Pronounced features of this concept include avoidance of the need for paper drying and elimination of various negative consequences related to rewetting of the paper with water, etc. However, to date the concept has not been commercialized. Some significant challenges remain. Commercializable technologies for production of size-controllable coating particles and their electrostatic deposition onto paper are the key. Reconsidering this interesting concept may at a minimum shed light on the technological advancement in the area of pulp and paper. [ABSTRACT FROM AUTHOR]

The penetration of ink into paper affects the final appearance of printing and the amount of ink usage. In this work, UV-curing fluorescent rose ink was used to investigate the penetration and distribution of the ink pigments as well as their correlation with the surface topography of paper. The ink penetration and distribution were characterized with Confocal Laser Scanning Microscopy (CLSM), whereas the microstructure of the paper surface was observed using Atomic Force Microscopy (AFM). The AFM results showed that the surface of the paper coated with kaolin layer was the smoothest among the samples. Also the pore size of the calcium carbonate coating layer was smaller than that of the kaolin coating layer. Meanwhile, the pore size distribution of the calcium carbonate coating layer appeared to be relatively narrow, compared with other samples. The results of CLSM images indicated that the depth, size, and arrangement of pores affected the penetration depth and distribution of ink pigment on coated paper. The large pores led to deeper penetration of ink pigments, and uniform ink absorption occurred when the pore distribution was uniform. The UV-curing ink pigments not only set on the surface of the uncoated paper, but also they penetrated into the paper interior and adhered to the fiber surface. [ABSTRACT FROM AUTHOR]

This research focused on the production of a novel calcium silicate pigment made from pulverized coal fly ash and its application as a coating pigment in a size press for fiber replacement. Improved specific base paper properties of the newsprint was investigated. This novel coated fly ash based calcium silicate (FACS) pigment and conventional precipitated calcium carbonate (PCC) pigment was applied using a cylindrical laboratory coater. When a 4.3 gsm coat weight of FACS was used during the size press application, the brightness increased 10 points, whereas, when the coat weight of FACS was increased to 7.8 gsm, the brightness increased to 21 points as compared to base newsprint sheet; however, FACS brightness was lower than the PCC coated newsprint sheet. Also, there was a significant gain in other newsprint specific base properties when fly ash based pigment was used. This indicated that it is feasible to utilize a novel fly ash based pigment in the size press coating application to replace fiber in order to reduce production cost, improve specific base properties, and reduce environmental pollution. To the authors' knowledge, this is the first study reporting the application of fly ash as a coating pigment for quality enhancement of newsprint. [ABSTRACT FROM AUTHOR]

Superhydrophobic materials have recently attracted great interest from both academia and industry due to their promising applications in self-cleaning, oil–water separation, etc. Here, we developed a facile method to prepare hybrid PDMS/TiO2 fiber for superhydrophobic coatings. TiO2 could be uniformly distributed into PDMS, forming a hierarchical micro/nano structure on the surface of the substrate. The contact angle of the superhydrophobic coating could reach as high as 155°. The superhydrophobic coating possessed good self-cleaning performance, corrosion resistance, and durability. It was found that gravity-driven oil–water separation was achieved using stainless steel mesh coated with the PDMS/TiO2 coating. More importantly, the coated filter paper could not only separate oil and pure water but also corrosive solutions, including the salt, acid, and alkali solution. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of size press coating on two types of recycled papers using different types of nanofibrillated cellulose (NFC) and cationic starch (CS) on physical and mechanical properties. Wheat straw was used as a cellulose source, and NFC was obtained through oxidative and enzymatic pretreatments. Recycled fluting and coreboard papers were coated with cationic starch/NFC blends at various concentrations of NFC (0.5%, 1%, 2%, 3%, and 4%) using a three-time repetitive size press application, followed by one-time drying section, and compared to uncoated papers. The application of a coating suspension containing 4% periodate-oxidized NFC on both paper surfaces resulted in a significant improvement in the tensile index, burst index, and internal bond strength of the papersheets, with increases of up to 60.6%, 96.3%, and 119.9%, respectively. Furthermore, significant decreases in air permeability were also observed with reductions of 75% and 81.6% for coreboard and fluting papers, respectively. Compared to other pretreatment methods, periodate oxidation resulted in higher viscosity values in NFC samples. Therefore, the application of periodate-oxidized NFC with a size press resulted in a significant improvement in the mechanical and barrier properties of papers made from recycled pulps. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) or PLA is a well-known biodegradable polymer derived from renewable resources such as corn strach, tapioca strach, and sugar cane. PLA is the most extensively utilized biodegradable polyester with potential to replace conventional petrochemical-based polymers. However, PLA has some drawbacks, such as brittleness and poor gas barrier properties. Nano composite polymers have experience and increasing interest due to their characteristics, especially in mechanical and thermal properties. The objectives of this research were to prepare PLA formulations using three different PLAs. The formulas giving high gloss coating film were selected to prepare nano composite film by incorporated with different amount of various types of organoclays. The physical properties of the PLA coating films were studied and it was found that the PLA 7000D with 0.1%w/w of Cloisite 30B provided decent viscosity for coating process. In addition, the nano composite coating films showed good physical properties such as high gloss, good adhesion, and good hardness. There is a possibility of using the obtained formulation as a paper coating film. [ABSTRACT FROM AUTHOR]

A series of multi-walled carbon nanotube (MWCNT)-coated cellulose papers were manufactured by a facile dip-coating process, and their performance in electric heating and electromagnetic interference (EMI) shielding materials was investigated by considering the microstructure, thermal stability, and electrical property. With increasing the cycle of the dip-coating process, the apparent thickness of MWCNT/cellulose papers increased on a monotonic basis. It was observed that MWCNTs are coated dominantly on cellulose fibers on the paper surfaces, in addition to their partial coating on the inside of cellulose papers, which is supported by the anisotropic electrical conductivity of the papers in the in-plane or thickness direction. For MWCNT/cellulose paper obtained by single dip-coating cycle, high apparent electrical conductivity in the in-plane direction of 0.02 S/cm was achieved. The electrical conductivity in the in-plane direction increased significantly from 0.02 S/cm to 1.11 S/cm with increasing the dip-coating cycle from 1 to 30. Accordingly, MWCNT/cellulose papers with >1 dip-coating cycle exhibited excellent electric heating performance in terms of temperature responsiveness, steady-state maximum temperature, and electrical energy efficiency at constant applied voltages. In addition, high EMI shielding effectiveness of ∼20.3 dB (∼99.1% attenuation) was achieved at 1 GHz by MWCNT/cellulose paper with ∼1.11 S/cm and ∼170 μm only. [ABSTRACT FROM AUTHOR]

In order to improve the whiteness of fly ash, the particles were coated by in-situ precipitation of calcium carbonate. After different mass ratios of calcium oxide to fly ash were mixed into water, a certain amount of carbon dioxide was bubbled into the mixture to form a precipitated calcium carbonate deposit on the surface of fly ash. With the help of scanning electron microscopy (SEM), the process and the coating mechanism of the unmodified and modified fly ash were studied. The results showed that when a 1:1 mass ratio of calcium oxide to fly ash was implemented, the whiteness of fly ash was increased from 30.3 (the original fly ash) to 74.0 (the modified fly ash). After appropriately controlling for the rate of carbon dioxide, the whiteness was improved to meet the standard for filler in the papermaking industry, and also great advantages in paper physical strength were demonstrated. [ABSTRACT FROM AUTHOR]

A chemo-mechanical model is developed to investigate the effects on the stress development of the coating of polycrystalline Ni-rich LiNixMnyCozO2 (x ⩾ 0.8) (NMC) particles with poly(3,4-ethylenedioxythiophene) (PEDOT). The simulation results show that the coating of primary NMC particles significantly reduces the stress generation by efficiently accommodating the volume change associated with the lithium diffusion, and the coating layer plays roles both as a cushion against the volume change and a channel for the lithium transport, promoting the lithium distribution across the secondary particles more homogeneously. Besides, the lower stiffness, higher ionic conductivity, and larger thickness of the coating layer improve the stress mitigation. This paper provides a mathematical framework for calculating the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coating of NMC active particles mitigates stress levels. [ABSTRACT FROM AUTHOR]

The demand for fiber-reinforced polymers (FRPs) has significantly increased in various industries due to their attributes, including low weight, high strength, corrosion resistance, and cost-efficiency. Nevertheless, FRPs, such as glass and Kevlar fiber composites, exhibit anisotropic properties and relatively low interlaminar strength, rendering them susceptible to undetected damage. The integration of real-time damage detection processes can effectively mitigate this issue. This paper introduces a novel method for fabricating embedded capacitive sensors within FRPs using a coating technique. The study encompasses two types of fibers, namely glass and Kevlar fiber/epoxy composites. The physical vapor deposition (PVD) technique is employed to coat bundle fibers with conductive material, thus creating embedded electrodes. The results demonstrate the uniform distribution of nanoparticles of gold (Au) along the fibers using PVD, resulting in a favorable resistance of approximately ≈100 Ω. Two sensor configurations are explored: axial and lateral embedding of the coated yarn (electrodes) to investigate the influence of load direction on the coating yarn. Axial-sensor configuration specimens undergo tensile testing, showcasing a linear response to axial loads with average sensitivities of 1 for glass and 1.5 for Kevlar fiber/epoxy composites. Additionally, onset damage is detected in both types of fiber composites, occurring before final fracture, with average stress at the turning point measuring 208 MPa for glass and 144 MPa for Kevlar. The lateral-sensor configuration for glass fiber-reinforced polymer (GFRP) exhibits good linearity towards strain until failure, with average gauge factors of 0.25 and −2.44 in the x and y axes, respectively. [ABSTRACT FROM AUTHOR]

Many different processes have been developed to grow graphene film to protect metals. These processes are primarily based on chemical vapour deposition and are challenging to scale. In this paper, we have attempted to grow the reduced graphene oxide (rGO)-like film using the natural resin 'shellac' as a precursor through the simple process of dip coating of shellac varnish and annealing of coated substrates in a reducing atmosphere. X-ray diffraction (XRD) analysis and Raman spectroscopy were used to establish the rGO phases grown in the coating. The corrosion studies of rGO films grown on cold-rolled interstitial-free steel are investigated with different loadings of shellac in the varnish solution and subsequent heat treatments. Scanning electron probe micro-analysis was done to do elemental analysis, and potentiometric studies were done to investigate the corrosion behaviour of the coatings. The structure–property correlation of the film has established the corrosion mechanism using different microscopy techniques. [ABSTRACT FROM AUTHOR]

Kenaf (Hibiscus cannabinus L.) is a relatively new industrial crop which has been identified as an alternative source of fiber in the papermaking industry in Malaysia. In this study, experimental unbleached kenaf kraft paper samples were used as a substrate to produce water-resistant paper by employing a special coating. In the preparation of the coating formulation, commercially precipitated calcium carbonate (PCC) was used as the filler, in addition to 0 to 0.32 w/w g of hydrophobic stearic acid (SA). Polymer latex (PL) was added at 0.4 to 0.16 w/w g into the coating compound to control the surface roughness of the samples. The paper morphology was examined by employing a scanning electron microscope (SEM). Hydrophobic kenaf kraft paper prepared in this study had water contact angle (θ) greater than 90°. Hydrophobic paper made with formulation PL4c resulted in the highest value contact angle of 147°. The process of surface coating by dipping increased the water contact angle and this treated paper achieved a high hydrophobic level. For mechanical properties, the coated kenaf paper showed decreasing tensile strength as the addition of stearic acid increased. [ABSTRACT FROM AUTHOR]

Carbon aerogel is a promising material in various applications, such as water treatment, insulators, catalysts, and sensors, due to its porosity, low density, conductivity, and good chemical stability. In this study, an inexpensive carbon aerogel was prepared through lyophilization and post-pyrolysis using waste paper. However, carbon aerogel, in the form of short belts, is randomly entangled without a crosslinking agent and has weak mechanical properties, thus limiting its applications, which would otherwise be various. In this paper, a novel strategy is proposed to fabricate a PDMS-coated carbon aerogel (Aerogel@PDMS). Benefiting from microwave heating, precise PDMS coating onto the carbon frame was able to be carried out in a short amount of time. PDMS coating firmly tied the carbon microstructure, maintaining a unique aerogel property without blocking its porous structure. FE-SEM, RAMAN, XPS, and FT-IR were all used to confirm the surface change in PDMS coating. Compressible stability and water contact angle measurement showed that Aerogel@PDMS is a perspective organic solvent absorbent due to its good resilience and its hydrophobicity, and, as a result, its organic solvent absorption capacity and repeated absorption were evaluated, ultimately suggesting a promising material in oil clean-up and pollution remediation in water. Based on our experimental results, we identified elastic carbon aerogels provided by a novel coating technology. In the future, then, the developed carbon/PDMS composite can be examined as a promising option for various applications, such as environmental sensors, virus sensors, and wearable sensors. [ABSTRACT FROM AUTHOR]

Herein, we fabricated a starch-based flexible coating for food packaging papers with excellent hydrophobicity and antimicrobial properties. FTIR (Fourier transform infrared) and XRD (X-ray diffraction) spectra revealed the homogeneous dispersion of the ZnO nanoparticles (NPs) in the composite film within 5% ZnO NP dosage. SEM (scanning electron microscope) and AFM (atomic force microscope) micrographs confirmed the increased roughness on the composite film with the increased dosages of ZnO NPs. Hydrophobic characteristics showed that dramatic enhancement was obtained in the values and stabilities of DCAs (dynamic contact angles) in the resultant film and coated paper. TG (thermogravimetry) results demonstrated the increased thermal stabilities of the composite films. Significantly, a decreased water vapor transmission rate was observed in the coated paper. When 20% guanidine-based starch and 2% CMC (carboxy methyl cellulose) was added, a flexible coating with excellent antimicrobial activity towards Escherichia coli can be obtained. Furthermore, the migration of ZnO NPs into the food simulants was well below the overall migration legislative limit. The resultant starch-based flexible composite film and coated paper established an effective approach to develop a green-based material for food packaging applications. [ABSTRACT FROM AUTHOR]

Abstract: Hyphenated techniques like Py-GC/MS (pyrolysis-gas chromatography/mass spectrometry) result often in complex chromatograms containing a high information density. Extracting meaningful information is difficult and time consuming. Especially with automatic sampling, data evaluation becomes a major bottleneck. An effective approach to automate the characterization of chromatograms is presented. The database approach consists basically of three steps: measuring reference substances to generate a database, measuring unknown or difficult samples and using the database for the identification of these samples. The compiled database contains a collection of mass spectra of pyrolysis products with data such as retention index and additional information from which reference substances the pyrolysis products may derive. The developed database approach has been tested on designed mixtures of compounds forming “white pitch”. “White pitch” is a typical type of deposit found in paper production processes deriving from chemicals used in coating processes. [Copyright &y& Elsevier]

Abstract: Preceramic papers loaded with inorganic fillers may be used as preforms in a novel manufacturing technique to fabricate lightweight ceramic structures. In order to reduce the porosity caused by burning out cellulosic fibers and organics, porous preceramic paper-derived alumina substrates were post-treated via two different coating routes using silica suspension or methylphenylvinylhydrogen polysiloxane. Sintering of the alumina-filled preceramic papers in air at 1600°C for 2h resulted in a non-uniform distributed open porosity ranging from 23 to 26%. After coating and infiltration, all samples were additionally heat treated up to at 1500°C for 2h. Thermal analysis (DTA/TG) was applied to determine the pyrolysis temperature of polysiloxane. Microstructure and phase analysis were performed respectively by SEM and XRD. After sintering, water absorption, apparent density and open porosity of test pieces were determined, and mechanical properties of the substrates were evaluated before and after coating. For the samples coated with silica suspension, the mechanical strength remained in the same range of those for uncoated samples, while for the polysiloxane coated samples the mechanical strength steadily increases after repeated impregnation steps, reaching ∼350MPa. [Copyright &y& Elsevier]

There are some important advantages presented by metal specimens coated with WIP-C1 (Ni/CrC)-type materials. However, given the coating methods and the stress under dynamic loads, there are issues that need to be taken into account, particularly in terms of the behavior at the interface between the two materials. Using standardized cylindrical 1018 steel specimens uniformly coated with WIP-C1 (Ni/CrC) by cold spraying, this study investigated the fatigue behavior of the specimen as a whole, focusing on the interface areas of the two materials. The fatigue life diagram is given, to a large extent, by the behavior of the base material. As a result, in this work, we have focused not so much on the fatigue behavior of the assembly as on the integrity of the coating material and the defects, failures, etc., that may occur at the interface after a certain number of cycles. The applied load was cyclic fatigue through alternating–symmetric cycles. Scanning optical microscopy was used to observe plastic deformations and crack propagation during the breakage process. It was found that both the base material zone and the cover material zone presented good performance when the maximum stresses were at low values. A fatigue durability curve was also plotted, showing a conventional appearance for a metallic material, slightly influenced by the destruction of the base material interface. At higher maximum stress and, consequently, to large strains, a series of destructions at the interface of the two materials, of different types, were observed and will be highlighted in the paper. [ABSTRACT FROM AUTHOR]

A novel process involving a paper-based ultrafiltration (UF) membrane was developed via paper coating technology. The membrane employed a paper sheet as support layer and a coated thin film layer of adhesive. The proper selection of paper sheet support layer was crucial to the performance of the ultrafiltration membrane. A paper sheet with beating degree of 85°SR and basis weight of 50g/m² was chosen as the support. PVA was chosen as the adhesive. The paper-based ultrafiltration membrane achieved high retention performance while using a simple production process and keeping the production cost low. Disadvantages of the membrane included low porosity and low pure water flux. So further investigation is still needed to produce a fully satisfactory paper-based ultrafiltration membrane. [ABSTRACT FROM AUTHOR]

In this study antibacterial coated paper packaging with improved properties were prepared from incorporation of nanoclay montmorillonite and antimicrobial triclosan into coatings. The materials were characterized by mechanical and antimicrobial tests, water barrier and thermal analysis. It was demonstrated that use of nanoclay increases significantly the tensile strength of coated papers, besides increase the thermal stability of them. All triclosan-containing papers presented inhibitory effect against Staphylococcus aureus and Escherichia coli. In addition, all coated papers presented superior water barrier due to coating process. The new nanocomposite developed shows great potential for antimicrobial packaging applications. [ABSTRACT FROM AUTHOR]

A new approach for the chemical modification of the surface of paper based on the application of colloidal mixtures containing cationic starch and polyoxometalates on uncoated base paper is presented. Polyoxometalates with the Keggin-type structure and physical properties similar to those presented by coating pigments, namely H3PW12O40∙23H2O, H4SiW12O40∙24H2O, and K7PW11O39∙9H2O, have been used in order to improve the quality of inkjet printing. The analysis of the different samples by FTIRATR spectroscopy showed the presence of the polyoxometalates (and the cationic starch) on the top surface of the paper. In addition, the determination of surface energy parameters, namely the polar component (σsp) and the dispersive component (σsd) of the surface energy, by contact angle measurements revealed that, for the new samples, the polar component level was much higher than that of the uncoated base paper. The quality of inkjet printing, evaluated by parameters such as the gamut area and the optical density, was considerably improved by these surface treatments. [ABSTRACT FROM AUTHOR]

Multiphysics models were used to simulate the deformational characteristics experienced by paper under metering blades. Paper is found to slip microscopically at the backing roll interface and subsequently buckle either side of the blade during metering operations. Micro-slippage of the paper at the interface is a linear function of the separation height incurred during buckling. The effects of altering the static coefficient of friction as well as the properties of the backing roll material are studied. Increasing the coefficient of static friction reduces the extent of buckling while a non-linear relationship is found to arise on increasing the elastic modulus of the backing roll material. The mechanisms involved in micro-buckling deformation are explicated herein. [Copyright &y& Elsevier]

The use of paper as a sustainable packaging material is favored, but it lacks sufficient barrier properties in terms of water repellence and oil resistance. Novel approaches consider active packaging materials or coatings with controlled release providing additional functionality for delivery of specific components to the surface. In this study, the development of a waterborne coating with organic nanoparticles and encapsulated sunflower oils is presented as a system for thermal release of the oil and on-demand tuning of the final barrier properties of the paper substrate. After synthesis of the nanoparticles, it seems that the encapsulation of various grades of sunflower oil (i.e., either poly-unsaturated or mono-unsaturated) strongly affects the encapsulation efficiency and thermal release profiles. The water contact angles are controlled by the oil release and chemical surface composition of the coating upon thermal heating. The oil resistance of the paper improves as a more continuous oil film is formed during thermal release. In particular, the chemical surface composition of the paper coatings is detailed by means of micro-Raman spectroscopy and surface imaging, which provide an analytical quantification tool to evaluate surface coverage, oil delivery, and variations in organic coating moieties. [ABSTRACT FROM AUTHOR]

Natural fibers do not have a long life in soil; therefore, they cannot replace synthetic textiles in many applications. However, in order to solve ever-increasing global environmental problems due to microplastics, more and more natural polymers must be used, creating a need for research into the sustainable life extension of natural fibers. Lignin is, along with cellulose, a main component of wood, and is produced in large quantities as waste during paper production. With appropriate processing, lignin can be exploited/used as a textile auxiliary to combine the strength-enhancing properties of textiles made from natural fibers with the protective properties of a lignin coating. However, there is not yet sufficient research on how to integrate lignin into textile applications. For this purpose, in this study, we have investigated whether thermoplastic lignin can be processed as a surface protective coating. We tested lignin as a yarn coating to extend the service life of cellulosic textiles. Cotton yarns have been coated with lignin in variations of coating mass, characterized and investigated by means of soil burial tests. As the soil burial tests conducted in climate chamber and outdoor field environments showed, the lifespan of textiles made from natural fibers can be significantly extended with a lignin coating. Long-term resilience has been demonstrated in standard burial tests. In the outdoor tests, the lignin coating was still fully intact, even after about 160 days of burial. The textile materials coated in this way enable sustainable applications, especially for geotextiles. They have an adjustable, sufficiently long service life; however, they are still biodegradable, and can therefore replace some applications, such as vegetating trench/brook slopes, with synthetic materials. Lignin-coated textiles have the potential to significantly reduce the carbon footprint, reduce not only the dependence on petroleum-based products but also the amount of microplastics entering the environment. Further research can be conducted to improve lignin compounding in terms of other interesting properties for specific textile applications. Process optimization could increase the protective effect and further extend the life of useful textiles in soil. [ABSTRACT FROM AUTHOR]

Micro hole is the fundamental feature found in any device and its components. Hence this paper aims to produce the micro holes using electrochemical micromachining (EMM). The existing machining techniques in EMM for creating micro holes are associated with more overcut (OC). Hence, reducing OC and enhancing the machining rate (MR) is essential. This paper aspires to investigate the effect of the graphite electrode with magnetic force on the copper plate. Four different tools, namely the electromagnetic graphite tool (EMGT), permanent magnet graphite tool (PMGT), graphite tool, and stainless steel (SS) tool, are employed for these experiments. The major influencing factors are machining voltage in volts, duty cycle in % and electrolyte concentration in g/l was considered on MR and OC. The results revealed that EMGT, PMGT, and graphite electrodes produce MR of 106.4%, 74.6 % and 44.5 % over the SS tool at a parameter level of 23 g/l, 15 V, and 85%, respectively. Furthermore, graphite and EMGT electrodes resulted in 11.9% and 3.41% reduced OC, respectively, than the SS tool at parameter levels of 8 V, 95% and 28 g/l. Additionally, the scanning electron microscope (SEM) picture examination is conducted to identify the magnetic field effect on the work surface. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have showed great potential for next-generation lighting and display technologies. However, its stability is still one of the key problems that limit its practical application. In this paper, by comparing the specific surface area (SSA) and pore width of aluminum oxide (AlO x) and silicon oxide (SiO 2) barrier layers, the relationship between the porosity of barrier layers and the stability of QDs was studied. The results showed that the synthesized SiO 2 -QD-AlO x , which has the smallest SSA in the synthesized QD composites, exhibited the best stability on the quantum dot diffuser plate (QD-DP). Moreover, the operational lifetime (T 80) at 450 nm blue light excitation was increased by a factor of 3.41 compared to that of bare QDs. Meanwhile, the prepared QD-DP containing dense SiO 2 -QD-AlO x composites significantly improved the resistance to light, heat, moisture and oxygen. Finally, the prepared QD-DP was assembled into a Mini-LED TV with a wide color gamut and excellent display performance (a color gamut of 157.4 % for commercial normal TV, and 107.19 % for the National Television System Committee (NTSC 1931)). This technique provides favorable guide for effectively enhancing the stability of QDs in lighting and display technologies. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have showed great potential for next-generation lighting and display technologies. However, its stability is still one of the key problems that limit its practical application. In this paper, by comparing the specific surface area (SSA) and pore width of aluminum oxide (AlO x) and silicon oxide (SiO 2) barrier layers, the relationship between the porosity of barrier layers and the stability of QDs was studied. The results showed that the synthesized SiO 2 -QD-AlO x , which has the smallest SSA in the synthesized QD composites, exhibited the best stability on the quantum dot diffuser plate (QD-DP). Moreover, the operational lifetime (T 80) at 450 nm blue light excitation was increased by a factor of 3.41 compared to that of bare QDs. Meanwhile, the prepared QD-DP containing dense SiO 2 -QD-AlO x composites significantly improved the resistance to light, heat, moisture and oxygen. Finally, the prepared QD-DP was assembled into a Mini-LED TV with a wide color gamut and excellent display performance (a color gamut of 157.4 % for commercial normal TV, and 107.19 % for the National Television System Committee (NTSC 1931)). This technique provides favorable guide for effectively enhancing the stability of QDs in lighting and display technologies. [ABSTRACT FROM AUTHOR]

Summary: The cellulose paper-based functional materials modified by Zn-NDI and Cu-NDI were prepared by the coating method. The chemical structures were characterized by FTIR, XRD, UV-vis and SEM, and the photochromic properties of the composite functional materials wer e studied. The results showed that Zn-NDI and Cu-NDI were successfully prepared and retained on the surface of copy paper, the wavelength of photochromic reaction is between 300-400 nm of MOFs materials. Optical analysis confirmed that the NDI/paper, Zn-NDI/paper and Cu-NDI/paper changed from tan to wheat, light green to olive, and dark tan to brown after 60 seconds of exposure to hernia light irradiations, the MOFs coated paper returned to its original color when it was placed in the dark for 4 hours. The above results indicated that the prepared Zn-NDI and Cu-NDI coated paper composites exhibited excellent photochromic ability and had potential applications in the field of anti-counterfeiting packaging materials. [ABSTRACT FROM AUTHOR]

In the long-term working state, stains such as dust, oil, and charged particles in the environment are prone to deposit on the surface of the power equipment, which has great security risks. To achieve anti-stain performance, fluorocarbon composite coating with a low surface energy was prepared and studied. In this paper, SiO2 nanoparticles were used as inorganic fillers and fluorocarbon resin was used as the substrate to form anti-stain coatings. By adjusting and optimizing the ratio of fillers and organic resins, coatings with different static contact angles were constructed. The optimum composite coating has a contact angle of 151 ± 2° and a surface energy of 9.6 mJ/m2. After high-temperature treatment (up to 200 °C), immersion in corrosive solutions (pH 3–11), and sandpaper abrasion (after 5 abrasion cycles), the coating has been proven to show good thermal, chemical and mechanical stability. Our study provides significant research and market opportunities for the anti-stain application of the fluorocarbon composite coating on power equipment. [ABSTRACT FROM AUTHOR]

• A simple approach is proposed to fabricate a Janus-paper with superhydrophobicity/superhydrophilicity. • When the prepared mimosa-like Janus-paper is immersed in water, it bends immediately like mimosa. • Janus-paper can significantly improve the cell biocompatibility. • Superhydrophobic and superhydrophilic surfaces can be used for microdroplet transportation. Janus-materials were processed though different characteristics integrate to achieve important functions which have aroused great interest among the scientific research and industrial applications. However, the facile fabrication of Janus-materials with the attributes of chemical-free, low-cost, and simple process is still a great challenge. Herein, inspired by the mimosa and lotus leaf, a Janus-paper with superhydrophobicity /superhydrophilicity is successfully fabricated by a conjunction of PDMS and candle soot coating. The water and sliding contact angles of the superhydrophobic surface are 162° and 1°, respectively, and it also shows a good antifouling properties and mechanical durability. Additionally, the cell biocompatibility of superhydrophobic surface is significantly improved, holding the potential as a cell culture carrier. Due to the inhomogeneous swelling inside the internal structure, the Janus-paper exhibits a mimosa-like behavior when immersed in water, endowing the actuation of a boat model on the water surface. Moreover, due to the different adhesions, the superhydrophobic and superhydrophilic surfaces can be used for microdroplet transportation and water storage devices. This bio-inspired approach provides a new generic route for fabrication of Janus-paper for potential multifunctional applications. [ABSTRACT FROM AUTHOR]

As one of the most abundant natural polymers in nature, polysaccharides have the potential to replace petroleum-based polymers that are difficult to degrade in paper coatings. Polysaccharide molecules have a large number of hydroxyl groups that can bind strongly with paper fibers through hydrogen bonds. Chemical modification can also effectively improve the mechanical, barrier, and hydrophobic properties of polysaccharide-based coating layers and thus can further improve the related properties of coated paper. Polysaccharides can also give paper additional functional properties by dispersing and adhering functional fillers, e.g., conductive particles, catalytic particles or antimicrobial chemicals, onto paper surface. Based on these, this paper reviews the application of natural polysaccharides, such as cellulose, hemicellulose, starch, chitosan, and sodium alginate, and their derivatives in paper coatings. This paper analyzes the improvements and influences of chemical structures and properties of polysaccharides on the mechanical, barrier, and hydrophobic properties of coated paper. This paper also summarizes the researches where polysaccharides are used as the adhesives to adhere inorganic or functional fillers onto paper surface to endow paper with great surface properties or special functions such as conductivity, catalytic, antibiotic, and fluorescence. [ABSTRACT FROM AUTHOR]

Porosity is closely related to the corrosion and wear properties of a coating processed by thermal-spraying technology, and the quantitative characterization of porosity is a crucial part of the research on coating structures. The current image analysis method often uses the mechanical polishing method recommended by ISO to measure a coating porosity. This method has been proved to be an effective method for the characterization of oxide coatings. However, due to the significant differences in the physical and chemical properties between aluminum and oxides, this method may not be suitable for aluminum coatings, and a more appropriate approach needs to be explored. In this paper, the effects of three polishing technologies (mechanical polishing, argon-ion-beam polishing, and electrolytic polishing) on the porosity measurement of pure aluminum coatings were compared and studied. The research results showed that the commonly used mechanical polishing method and more advanced argon-ion-beam polishing method could not completely reveal the pore structure because SiC particles would be embedded in the pure aluminum coatings during mechanical polishing, filling large pores. Although electrolytic polishing technology had advantages in revealing the macroporous structure, it would introduce a microporous structure and oxides, which would affect the measurement of the coating porosity. The composite polishing technology (electrolytic polishing + argon-ion-beam polishing) could perfectly reveal the pore structure in the pure-aluminum coating, and the porosity of arc-sprayed aluminum coating was 9.9%, which was close to the macroscopic true value measured using the weighing method of 10.2%. [ABSTRACT FROM AUTHOR]

Due to its chemical structure and the resulting dielectric properties, the processing of the commonly used particle foam material, expanded polypropylene (ePP), is limited. Processing within the radio-frequency welding process is therefore only possible with the use of processing aids. In this paper, a new approach for the use of a solid and dielectric heatable coating for the production of three-dimensional welded components out of ePP is presented. For this purpose, three different types of water-soluble polymer polyvinyl alcohol (PVA) were analyzed as potential coating materials. The thermal and dielectric properties of the coating were further adjusted by a modification with glycerol. The maximum amount of glycerol tested was 25% by volume. It influences both the temperature development in the radio-frequency (RF) welding process as well as the adhesive bond between the ePP foam particles. It is shown that the 120 °C approach in the RF welding process resulted in a cohesive bond between the coating layers. In this way, bonded plates can be produced. In mechanical tests with compression of 20%, the manufactured plates show sufficient load capacity. Furthermore, it can be shown that a separation of PVA and ePP by type, and thereby a separation of the foam particles, is possible with the use of hot water. This might open a new way for recycling of particle foams. [ABSTRACT FROM AUTHOR]

The increasing usage of petroleum-based compounds has prompted numerous environmental concerns. Consequently, there has been a steady rise in research on the synthesis of useful materials from natural sources. Paper technologists are seeking environmentally acceptable dry end and wet end additives. Among the bio-based resources available, nanocellulose is a popular sustainable nanomaterial additive in the paper industry because of its high strength, high oxygen barrier performance, low density, great mechanical properties, and biocompatibility. NC’s extensive hydroxyl groups provide a unique possibility to dramatically modify the hydrophilicity and charge of the surface in order to improve their potential applications in the paper industry. The current paper reviews two series of surface modifications, each with various subcategories, depending on why modified nanocellulose is added in the paper production: to improve barrier properties or to improve mechanical properties of packaging materials. The methods presented in this study use the minimum amount of chemically hazardous solvents to have the least impact on the environment. This review focuses on modifications of nanocellulose and their subsequent application in the papermaking. The knowledge and the discussion presented in this review will form a literature source for future use by various stakeholders and the sustainable paper manufacturers. [ABSTRACT FROM AUTHOR]

This paper systematically introduces the application status of coating-preparation technology on light alloys in the field of aviation parts repair. Included are the advantages and disadvantages of thermal spraying technology and laser cladding technology in the application process, as well as the research status and application prospects of the emerging cold spray (CS) technology and supersonic laser deposition (SLD) technology. Compared with traditional thermal-spraying technology, CS has many advantages, such as low spraying temperature, low oxygen content of the coating, and low porosity, which can effectively avoid oxidation, burning loss, phase change, and grain length during thermal spraying. CS can prepare oxygen-sensitive, heat-sensitive, amorphous, and nanomaterial coatings that are difficult to prepare by traditional thermal-spraying technology. However, in the preparation of high-strength super-hard alloys, CS has shortcomings such as low deposition efficiency and bonding strength. SLD overcomes the shortcomings of CS while inheriting the advantages of CS. In the future, both technologies will be widely used in repairing and remanufacturing in the field of aviation. Based on the principles of CS and SLD, this paper introduces, in detail, the deposition mechanism of the coating, and the specific application examples of CS in the aviation field at the present stage are described. The research and application status of the two technologies in the fields of anti-corrosion coating, wear-resistant coating, functional coating, repair, and remanufacturing in recent years are reviewed. Finally, the application and development prospects of CS and SLD are discussed. [ABSTRACT FROM AUTHOR]

This paper contributes to broadening the knowledge regarding coated PCBN tool wear in the finish turning operations of nickel-based superalloy GH4202. Three different coating PCBN tools (uncoated, TiN, and TiAlN) were used for finishing turning of superalloy GH4202. Cutting tests were carried out at a wide range of cutting speeds (vc = 50–400 m/min). Two different cutting conditions (dry and wet cutting) were also introduced. Aspects of tool wear and generated surface quality were studied. It was found that the protective function of the coating was limited only to the low cutting speed range. EDS analysis was used to analyze the wear mechanism under different cutting speeds. Different coatings exhibited different performance under different working conditions. The TiN coating was the most sensitive to the cutting coolant, and the uncoated tool was the most stable. Significant deposition of wear products was observed at high cutting speeds with the addition of cutting coolant. [ABSTRACT FROM AUTHOR]