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Atmospheric pressure plasma polymerization represents a promising coating technology, addressing drawbacks of traditional processes (solvent use, multistep procedures, etc.) while enabling deposition of thin cross‐linked polymer layers with high contour fidelity. We address technological challenges with a novel plasma device that integrates multiple plasma source benefits and investigate the suitability of two plant‐based precursors, chia and tung oil, for plasma polymerization to hydrophobize glass and paper. Chia oil enables the deposition of thin, covalently bonded hydrophobic polymer layers. Such coatings have diverse applications especially inside the paper industry, where water repellents in the form of internal and surface sizing have always been an essential functionalization step. Using bio‐based precursors and reducing extra chemicals contributes to substituting fossil‐based or harmful substances. [ABSTRACT FROM AUTHOR]

Nanocellulose has received enormous scientific interest for its abundance, easy manufacturing, biodegradability, and low cost. Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) are ideal candidates to replace plastic coating in the textile and paper industry. Thanks to their capacity to form an interconnected network kept together by hydrogen bonds, nanocelluloses perform an unprecedented strengthening action towards cellulose‐ and other fiber‐based materials. Furthermore, nanocellulose use implies greener application procedures, such as deposition from water. The surface chemistry of nanocellulose plays a pivotal role in influencing the performance of the coating: tailored surface functionalization can introduce several properties, such as gas or grease barrier, hydrophobicity, antibacterial and anti‐UV behavior. This review summarizes recent achievements in the use of nanocellulose for paper and textile coating, evidencing critical aspects of coating performances related to deposition technique, nanocellulose morphology, and surface functionalization. Furthermore, beyond focusing on the aspects strictly related to large‐scale coating applications for paper and textile industries, this review includes recent achievements in the use of nanocellulose coating for the safeguarding of Cultural Heritage, an extremely noble and interesting emerging application of nanocellulose, focusing on consolidation of historical paper and archaeological textile. Finally, nanocellulose use in electronic devices as an electrode modifier is highlighted. [ABSTRACT FROM AUTHOR]

A lignin-based PU coating was prepared for paper-based green packaging. Two representative diisocyanate were used to prepare the coatings. Due to the rigid aromatic, the physical properties of the TDI system reached the maximum below the lignin content of 40%. The HDI that contains flexible aliphatic chains alleviated the brittleness of coating, and it showed physical advantages when the lignin content was more than 50%. Owing to the high lignin content, the coating presented enhanced thermal stability. After coated with the lignin-based PU coatings, the dry tensile strength of coated paper was improved by 126%. Amazingly, the wet strength was increased from 0.31 to 12.6 MPa with an improvement nearly 40 times. Based on the coordination of lignin, Ag+ was introduced into the PU matrix, which imparted the coating with excellent antibacterial ability. The colony forming units of E. coli and S. aureus were both less than 1. However, no inhibition halo was observed, which indicated that the Ag was firmly anchored on the coating and the antibacterial ability is only available when the bacterial contact the coating surface. The lignin-based PU coating with favorable sustainability and properties shows great potential in paper-based green packaging fields. The prepared PU coating with high lignin content and firmly anchored Ag+ exhibits outstanding physical properties, thermal stability, and antibacterial property, which makes it an ideal candidate to be used in paper-based green packaging. [Display omitted] [ABSTRACT FROM AUTHOR]

Coatings are generally applied for opacity, smoothness and gloss on the paper surface. Pigments such as CaCO3, Kaolin-Clay and Zeolite are used, and natural or synthetic binders are used. In this study, coatings using the CaCO3, Kaolin-Clay and Zeolite pigments on 80 gr/m2 high grade papers were made. PVOH was used as binder. Following coating, papers were processed through supercalendaring and printed with inkjet printer. Using INGEDE method 11p. recycling process printed papers were deinked. The optical properties of the recycled papers obtained after the deinking treatment, were compared with the unprinted papers. At the end of the study, the effect of coating on paper surface and the recycling performances of the inkjet printed papers were revealed. It was determined that the papers in which zeolite was used as a pigment were better, in terms of both surface properties and recycling performance when surface properties and recycling performance of coated papers were examined. When all the results were compared, it was found that the performances of coatings for which zeolite was used were much better than coatings such as CaCO3 and Kaolin-Clay, both in terms of surface coating properties such as opacity, roughness and gloss and recycling results such as brightness. [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]

Limnocharis flava is a noxious aquatic weed that poses a threat to paddy cultivation. The high cellulose and low lignin contents in this plant make it a potential raw material for papermaking. Against this backdrop, this study was taken up to develop Limnocharis flava (LF) based sheets containing natural fibres from Banana (B), Pineapple (P), and Rice Straw (RS) as reinforcing agents. The influence of carboxymethyl cellulose (CMC) as a binder on the LF-based sheets was also studied. To enhance the mechanical and moisture resistance properties, a chitosan coating was provided to the sheets. Analytical tests for mechanical properties, water barrier properties, functional groups, structure and microstructure, thermal properties and biodegradability were performed. Among the samples, LF + B showed the highest tensile strength (34.86 Mpa) and bursting strength (13.055 kg/cm2), while LF + R had higher puncture and tearing strengths. Chitosan coating was found to enhance the sheets and improve the water barrier properties mechanically. The contact angle of LF + B increased from 91.6° to 110.65°, while the water vapour transmission rate of LF reduced from 532.18 to 404.47 on providing chitosan coating. The significant interactions of reinforcing agents were confirmed by the results of FTIR and that of the coating by the SEM micrographs. The LF-based sheets were also found to have decent thermal stability. The high value of the crystallinity index in LF + R samples supported their remarkable mechanical properties. This study proclaims the notable suitability of Limnocharis flava in manufacturing paper for packaging applications. [Display omitted] • Limnocharis flava based composite sheets were developed for packaging applications • Bio coating using chitosan was applied to enhance quality parameters • The developed material had impressive mechanical and water barrier properties • The developed material was used for cardamom packaging alternative to wood pulp /plastic packaging [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]

Raman spectroscopy and micro-Raman mapping have been used to study the distribution of different chemical components at the surface of coated papers. The paper coatings contain organic nanoparticles with a structure of poly(styrene-co-maleimide) and encapsulated vegetable oils. Raman spectroscopy is able to differentiate between various types of oil, i.e., polyunsaturated, monounsaturated, or saturated, and indicates that the degree of imidization and reactivity of the oil (amount of free oil) complement each other. The surface mapping over large areas (5 × 5 mm2) illustrates good homogeneity of the coating layer and even surface coverage. The imide and oil are homogeneously distributed within the coating itself without a tendency for agglomeration. The covered areas of imide and oil mostly overlap for polyunsaturated oils, while larger amounts of oil occur outside the imide zones for monounsaturated and saturated oils. The latter indicates that the oil is partly "free" within the coating and acts as a continuous binder phase. The surface mapping over smaller areas (1 × 1 mm2) shows the coating and cellulose covered areas are complementary. The surface maps confirm that interaction between the coating and paper substrate happens through hydrogen bonding. Heterogeneities in the coating are due to the presence of remaining ammonolyzed maleic anhydride precursors forming amic acid moieties. The organic phase, oil phase, and cellulose substrate can also be differentiated by principal component analysis of the surface maps. [ABSTRACT FROM AUTHOR]

Recently shown to meet regulatory requirements for safety assessment, high-performance thin-layer chromatography hyphenated with the SOS-Umu-C bioassay and S9 metabolization was applied to various food contact material prototypes, such as paper, plastic and coating samples. Studying reversed versus normal phase separation and piezoelectrical spraying versus syringe dosage of the bioassay, 14 genotoxic bands were detected. Three epoxides of linolenic acid were identified as genotoxic candidates in the paper migrate by heated electrospray and atmospheric pressure chemical ionization high-resolution mass spectrometry. These were confirmed by co-chromatography with linolenic acid epoxides. Comparatively poorer detection limits of in vitro microtiter plate bioassays and opposing effects/signal responses in the sample explained false-negative responses for paper migrate. However, the in vitro SOS-Umu-C microtiter plate bioassay confirmed the genotoxicity of a simulated linolenic acid epoxidation, and after sample concentration, the paper migrate mutagenicity was confirmed by the Ames-MPF™ bioassay. • On-surface metabolic activation via S9 system studied by piezoelectric spraying. • Assay application investigated via two techniques (ChromaJet versus Derivatizer). • Genotoxic compounds detected in migrates of packaging material. • Genotoxic epoxides of linolenic acid identified in paper migrate. • NP/RP-HPTLC−Vis/FLD−(S9)–SOS-Umu-C bioassay and −APCI/HESI-HRMS. [ABSTRACT FROM AUTHOR]

Fourier transform Raman spectroscopy and (dispersive) confocal Raman microscopy have been applied to quantitatively and qualitatively describe the local distribution of chemical moieties of poly(styrene- co -maleimide) coatings on paper substrates containing different amount of imide. In parallel, local coating defects have been imaged for a better understanding of the influence of the coating composition on homogeneity at macro- to microscale levels. From FT-Raman spectroscopy, the imide content was calculated in quantitative agreement with previous thermoanalytical data. From dispersive spectroscopy, the measuring parameters were optimized for single-point measurements including signals of the coating and macropoint measurements including more intense signals of the paper. The large surface maps (5 × 5 mm 2 ) provided good quantification for the lateral distribution of imide moieties and coverage for coatings with different thickness and imide content, based on relative intensities of imide/styrene and imide/cellulose bands. The inhomogeneities were related to the formation of surface patterns for coatings with high viscosity and presence of non-imidized residues. From detailed surface maps (1 × 1 mm 2 ), sensitive Raman bands were selected to describe variations in imide and styrene concentrations, conformations and interactions with fillers and cellulose. Based on data from Raman analysis, interactions between nanoparticles and cellulose possibly happened through hydrogen bonding. [ABSTRACT FROM AUTHOR]

The appearance or printing quality of paper surfaces is mostly characterized by their glossiness, measured with a glossmeter as specular reflectance. The gloss properties of a base paper substrate can be improved after application of a poly(styrene-co-maleimide) nanoparticle coating under pure conditions or in the presence of different vegetable oils. The specular gloss properties of 11 different nanoparticle paper coatings have been determined under 75° and 85° incident light angles, with good relation between values along parallel (machine) and perpendicular (transverse) direction. The gloss properties for the different coatings have been further related to the surface topography. Therefore, the statistical and spatial surface roughness parameters have been studied in detail at two length scales including non-contact profilometry (1 × 1 mm2) and atomic force microscopy (2 × 2 μm2). Based on values of the Rayleigh parameter for non-contact profilometry, the surfaces can be considered as optically rough. The gloss values cannot be directly related to statistical surface roughness parameters. Otherwise, an experimental power-law model for gloss has been proposed as a function of (β/Sq) with correlation length β and root-mean-square roughness Sq. A best-fit model illustrates that gloss properties of various nanoparticle paper coatings mainly relate to the spatial surface roughness parameters determined from non-contact profilometry. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 596-610, 2016 [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the feasibility of using highly filled powders as electrostatically applied paper coatings. Powders prepared by two different methods were suitable for electrostatic deposition and they attached to the paper surface with a grounded backing. Pressing at elevated temperatures turned out to be a crucial process step for improving the adhesive and cohesive strengths of the powder coating layer on paper. Limited mechanical interlocking with the base paper and an uneven pressure profile were factors impairing the surface strength of the coated paper. On the other hand, factors such as higher polymer content, higher pressing temperature, pre-heating the paper prior to coating, and increasing the number of hot roll nips increased adhesion between the coating and the base paper. Powder coatings as such had uneven thickness, and they displayed a relatively broad pore size distribution. [ABSTRACT FROM AUTHOR]

In parallel with the development of nanoparticle coatings for protection of paper substrates, detailed descriptions of the surface topography with micro- to nanoscale roughness features are needed. In this work, papers have been coated with poly(styrene-co-maleic anhydride) nanoparticles including different types of vegetable oils and the surface roughness was evaluated at 2000 × 2000 μm 2 to 0.2 × 0.2 μm 2 length scales by combining non-contact optical profilometry (NCP) and atomic force microscopy (AFM). The relationships between roughness data were studied for statistical roughness parameters, spatial roughness parameters and in the frequency domain. In order to compare AFM roughness more accurately, the original images were flattened to remove effects of the underlaying fibrous substrate and highlight features of the nanoparticle coating. More detailed information on the coating topography could be obtained by considering bearing ratio curves and histograms, where it was concluded that the oil-filled coatings form a rather thin and continuous coating that closely follows the shape of the cellulose fibers. The relation between statistical roughness parameters from NCP and AFM follows an exponential trend with relatively low coefficient of determination. The increase in surface roughness with length scale showed a transition point attributed to short- and long-range surface features. Therefore, the correlation length was used as a spatial roughness parameter that provides a successful extrapolation of the average roughness over different length scales in a double logarithmic diagram with very high coefficient of determination. Based on the power spectral density, it was difficult to exactly distinguish between the different types of SMI/oil coatings, as they include similar nanoscale features. The frequency roughness parameters were better suited for extrapolation than statistical roughness parameters but little less efficient than the spatial roughness parameters. [ABSTRACT FROM AUTHOR]

Newly developed packaging paper made of biopulped pineapple leaf fiber (PALF) and poly(lactic acid)(PLA) was studied. PALF packaging sheets were solvent impregnated with PLA at different concentrations in order to improve their moisture barrier and mechanical performance. With the impregnation of PLA at a concentration of 4%, the packaging material exhibited a low moisture uptake and a high tear index. An electron micrograph of the sample at 4% impregnation revealed uniform and packed PLA reversed microsphere morphology. These results suggest that surface coating via biodegradable polymers, such as PLA, may be utilized for manufacturing packaging materials in industrial applications. This new packaging material could reduce the dependency on woodbased paper and plastic-based packaging. [ABSTRACT FROM AUTHOR]

The effect of nanosilica particles on the water resistance of a polyurethane/nanosilica composite coated paper substrate was investigated. The polyurethane/nanosilica composite coating was prepared by dispersing nanosilica powder into solvent-based polyurethane using high mechanical stirring force. Paper substrate was coated with polyurethane/nanosilica composite using a Rod Mayer technique. Various compositions of polyurethane/nanosilica composite coatings on paper substrate were prepared. The total thickness of the paper coated with polyurethane/nanosilica composite was 0·3 mm. The field emission scanning electron microscopy images indicated that the presence of nanosilica has improved the surface roughness and porosity of paper substrate. The addition of nanosilica in polyurethane coating had increased the water resistance ability of the coated paper. It was demonstrated that polyurethane/nanosilica-6% shows better water resistance and exhibits better thermal stability than the nanocomposites with lower nanosilica loading. Fourier transform infrared spectroscopy result shows that there was no chemical reaction between nanosilica and polyurethane. [ABSTRACT FROM AUTHOR]

This review describes the state-of-the-art of material derived from the forest sector with respect to its potential for use in the packaging industry. Some innovative approaches are highlighted. The aim is to cover recent developments and key challenges for successful introduction of renewable materials in the packaging market. The covered subjects are renewable fibers and bio-based polymers for use in bioplastics or as coatings for paper-based packaging materials. Current market sizes and forecasts are also presented. Competitive mechanical, thermal, and barrier properties along with material availability and ease of processing are identified as fundamental issues for sustainable utilization of renewable materials. [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]

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]

Abstract: Papers have a complex hierarchical structure and the end-user functionalities such as hydrophobicity are controlled by a finishing layer. The application of an organic nanoparticle coating and drying of the aqueous dispersion results in an unique surface morphology with microscale domains that are internally patterned with nanoparticles. Better understanding of the multi-scale surface roughness patterns is obtained by monitoring the topography with non-contact profilometry (NCP) and atomic force microscopy (AFM) at different sampling areas ranging from 2000μm×2000μm to 0.5μm×0.5μm. The statistical roughness parameters are uniquely related to each other over the different measuring techniques and sampling sizes, as they are purely statistically determined. However, they cannot be directly extrapolated over the different sampling areas as they represent transitions at the nano-, micro-to-nano and microscale level. Therefore, the spatial roughness parameters including the correlation length and the specific frequency bandwidth should be taken into account for each measurement, which both allow for direct correlation of roughness data at different sampling sizes. [Copyright &y& Elsevier]

Abstract: The objective of the present work was to understand how the structural, surface, water vapour and gas barrier properties of wheat gluten (WG) coated paper could be influenced by the features of paper. For this purpose, a surface treated paper (TP) and an untreated paper (UTP) were compared. Penetration of WG-coating into the bulk of paper was more pronounced in UTP than TP. This led to the formation of a significant junction zone resulting in an interpenetrated structure for WG–UTP, suggesting a composite-like structure, while a bi-layer one was obtained for WG–TP. Differences in WG penetration were related to the hydrophilicity, roughness and porosity of the paper used. Even though the extent of penetration did not greatly affect the surface properties (water and oil resistance), the transfer properties (water vapour, O2 and CO2) of WG-coated papers were significantly improved when WG-coating highly penetrated: while the WG–TP behaved as a micro-perforated material, the WG–UTP behaved as WG-film. [Copyright &y& Elsevier]

Abstract: The objective of this work was to compare and understand the aroma compound barrier property of two impregnated–supercalendered papers, with or without surface coating, and one plastic film (BOPP) in standard conditions of temperature (25°C) and relative humidity gradient (50%) for foodstuff storage. For that purpose, solubility, diffusivity and permeability coefficients were determined for a homologous series of ethyl esters with a range of physico-chemical properties and vapor concentrations. Whatever the aroma compound and its vapor concentration, the non-coated paper was the more permeable; the coated paper and BOPP presenting close and lower permeability values. The transfer behavior was mainly controlled by aroma compound diffusivity related to packaging microstructure. Mutual affinity between aroma compound and packaging surface, determined experimentally or estimated, was related to their respective hydrophobicity. Conversely to papers which were treated to become more hydrophobic, BOPP was surface-treated to become more hydrophilic. In the conditions of the study, ethyl hexanoate sorption slightly increased BOPP crystallinity. [Copyright &y& Elsevier]

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]

Abstract: Antimicrobial papers were prepared by coating paper with soy protein isolate (SPI) solution as inclusion matrix of carvacrol, an antimicrobial agent. Addition of carvacrol (30% w/w of SPI) to SPI solution (10% w/v) prepared at 25°C induced soy protein aggregates and viscosity decrease. Heat treatment (50, 70, 90°C) of SPI solutions and carvacrol addition improved homogeneity reduced particles size and increased viscosity of solutions. The aggregated structure of SPI in the presence of carvacrol at 25°C may play the role of a trapping structure leading to low carvacrol losses during coating and drying process of paper (9.6% against 37% after heat treatment at 90°C) and to lower release rates specially the first three days (0.04g/m2/day and 0.31g/m2/day when SPI coating solutions were prepared at 25 and 90°C, respectively). Regardless of the heat treatments received by the SPI solutions, residual carvacrol quantities in the coated papers after 50 days ranged between 0.6 and 0.7g/m2. [Copyright &y& Elsevier]

Abstract: The need for kaolin pigments by the paper industry with controlled optical and physical properties have significantly changed the type of filler and coating clays available to the paper industry. Processing equipment now used in the production of kaolin products is much more sophisticated and controllable than in the past. Better understanding of the mineralogy and the physical and chemical properties of kaolins, in addition to improved processing techniques, has allowed the kaolin processors to produce engineered or tailored grades that meet particular needs of the user. Particle size and shape, brightness, gloss, opacity, and viscosity can be altered and controlled to meet specific requirements of the paper coater. Examples of several types of engineered products available for use by the paper industry are discussed. [Copyright &y& Elsevier]

The migration of five surrogate contaminants, anthracene, benzophenone, dimethyl phthalate, methyl stearate and pentachlorophenol, from paper and paperboard into water through a polyethylene (PE) coating layer was investigated. Virgin paper and paperboard coated with PE films of 0.012 and 0.030mm thickness were spiked evenly with standard 1-ml solutions containing 5mg of each surrogate. The spiked papers were placed in contact with the PE coating layer at 10 and 24 °C for 21 days. The resulting surrogate migration through the PE layer into 100ml water was measured by an analytical method developed here that used gas chromatography equipped with a flame ionization detector. Non-polar surrogates of anthracene and methyl stearate did not show any significant migration. In the case of the thin layer coating of 0.012mm, polar water-soluble contaminants of benzophenone, dimethyl phthalate and pentachlorophenol showed an equilibrated or maximized migration after 1 day, even at a refrigerated temperature of 10 °C. A thick PE coating of 0.030mm thickness delayed the progress of contaminant migration, which was also slower at lower temperature. Our results indicate that polyethylene coatings should not be seen as a complete barrier against possible contaminants in paper packaging materials under chilled or ambient conditions. Several variables such as coating thickness, temperature and suspected contaminants need to be considered to control the possible contamination risk from recycled or printed paper. [ABSTRACT FROM AUTHOR]

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]

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]

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]