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Mass-impregnated (MI) cables have been used for many years as cables in high-voltage direct current (HVDC) systems. In line commutated converter (LCC) HVDC systems, polarity reversal for power flow control can induce significant electrical stress on MI cables. Furthermore, the mass oil and kraft paper comprising the impregnated insulation have significantly different coefficients of thermal expansion. Load fluctuations in the cable lead to expansion and contraction of the mass, creating pressure within the insulation and causing redistribution of the impregnant. During this process, shrinkage cavities can form within the butt gaps. Since the dielectric strength of the cavities is lower than that of the surrounding impregnation, cavitation phenomena in impregnated paper insulation are considered a factor in degrading insulation performance. Consequently, this study analyzes the electrical conductivity of thermally aged materials and investigates the transient electric field characteristics within the cable. Additionally, it closely analyzes the formation and dissolution of cavities in MI cables during polarity reversal based on a numerical model of pressure behavior in porous media. The conductivity of the impregnated paper indicates that it has excellent resistance to thermal degradation. Simulation results for various load conditions highlight that the interval of load-off time and the magnitude of internal pressure significantly influence the cavitation phenomenon. Lastly, the study proposes stable system operation methods to prevent cavitation in MI cables. [ABSTRACT FROM AUTHOR]

The lifespan of an electrical transformer, primarily determined by the condition of its solid insulation, is well known under various operating conditions when mineral oil is the coolant in these machines. However, there is a trend toward replacing this oil with biodegradable fluids, especially esters; therefore, an understanding of the ageing of solid insulation with these fluids is essential. Currently available data do not allow for the selection of the best ester among those available on the market, as each study applies different conditions, making it impossible to compare results. Thus, this paper analyses the degradation of Kraft and Thermally Upgraded Kraft papers with the following five most promising commercial esters: sunflower, rapeseed, soybean, palm, and synthetic. The materials underwent accelerated thermal ageing at 130, 150, and 170 °C, and the integrity of the papers was evaluated through their polymerisation degree and the obtaining of the degradation kinetic models. The wide range of materials studied in this work, which were subjected to the same treatments, allows for a comparison of the esters, revealing significant differences in the impact of the alternative fluids. Sunflower, rapeseed, and soybean esters provided the best paper protection, i.e., the degree of polymerisation of Kraft paper in the tests at 150 °C decreased by 71% with these fluids, compared to the 83% reduction with mineral oil, 79% reduction with palm ester, and 75% reduction with synthetic ester. Furthermore, different kinetic models were obtained to predict the degradation; it was concluded that the Emsley model provides the best fit. Additionally, it was found that the behaviour of a dielectric fluid with one type of paper cannot be extrapolated, which is only noticeable in broad-scope studies. [ABSTRACT FROM AUTHOR]

Polyethylene-, polyvinylidene chloride-, and per- and polyfluoroalkyl substance-coated paper generate microplastics or fluorochemicals in the environment. Here, we report an approach for the development of oil-resistant papers using an environmentally friendly, fluorine-free, water-dispersible poly(dimethylsiloxane) (PDMS) coating on kraft paper. Carboxylic-functionalized PDMS (PDMS-COOH) was synthesized and subsequently neutralized with ammonium bicarbonate to obtain a waterborne emulsion, which was then coated onto kraft paper. The water resistance of the coated paper was determined via Cobb60 measurements. The Cobb60 value was reduced to 2.70 ± 0.14 g/m2 as compared to 87.6 ± 5.1 g/m2 for uncoated paper, suggesting a remarkable improvement in water resistance. Similarly, oil resistance was found to be 12/12 on the kit test scale versus 0/12 for uncoated paper. In addition, the coated paper retained 70–90% of its inherent mechanical properties, and more importantly, the coated paper was recycled via pulp recovery using a standard protocol with a 91.1% yield. [ABSTRACT FROM AUTHOR]

Though paper is an environmentally friendly alternative to plastic as a packaging material, it lacks antibacterial properties, and some papers have a low resistance to oil or water. In this study, a multifunctional paper-coating material was developed to reduce the use of plastic packaging and enhance paper performance. Natural cellulose nanocrystals (CNCs) with excellent properties were used as the base material for the coating. The CNCs were functionalized into dialdehyde CNCs (DACNCs) through periodate oxidation. The DACNCs were subsequently complexed using erythrosine as a photosensitizer to form an erythrosine–CNC composite (Ery-DACNCs) with photodynamic inactivation. The Ery-DACNCs achieved inactivations above 90% after 30 min of green light irradiation and above 85% after 60 min of white light irradiation (to simulate real-world lighting conditions), indicating photodynamic inactivation effects. The optimal parameters for a layer-by-layer dip coating of kraft paper with Ery-DACNCs were 4.5-wt% Ery-DACNCs and 15 coating layers. Compared to non-coated kraft paper and polyethylene-coated paper, the Ery-DACNC-coated paper exhibited enhanced mechanical properties (an increase of 28% in bursting strength). More than 90% of the bacteria were inactivated after 40 min of green light irradiation, and more than 80% were inactivated after 60 min of white light irradiation. [ABSTRACT FROM AUTHOR]

For shaped charge blasting projects in mining, civil engineering, and similar fields, it is proposed to modify the charge structure by combining slotted tubes and shaped charge liners to obtain a new type of charge structure. This aims to achieve directional rock breaking through the focused action of the shaped charge. The influence of different slotted pipe materials on the directional rock-breaking effect of concentrated energy using a new charge structure is explored through theoretical analysis combined with model test study, high-speed camera, stress–strain gauge, and other equipment. A comparison is made between slotted pipes made of aluminum, kraft paper, and PVC, with the cutting width of 2 mm. Based on the characteristics of the cracks formed after blasting, the new charge structure made of aluminum slotted pipe produces a penetrating crack that is almost consistent with the pre-cracking direction. Based on the corresponding characteristics of successively released blasting energy, the guiding and convergence effect of the new charge structure made of aluminum slotted pipe on the explosion energy is greater than that of the new charge structure made of the other two types of slotted pipe material. According to the strain data measured after blasting, the peak arrival time of the strain peak in the direction of the slotted pipe on one side of the shaped hood is shorter than that in the other two directions, and the peak strain is greater than that in the other two directions while having a better energy gathering effect. Based on the findings, the new charge structure with directional energy concentration has a damage reduction effect. Furthermore, the material of aluminum slotted pipe is found to be better than PVC slotted pipe, whereas the material of PVC slotted pipe is better than kraft paper slotted pipe in achieving directional rock breaking. [ABSTRACT FROM AUTHOR]

Contact and repellent toxicities of essential oil from Cnidium monnieri (L.) Cuss. (Apiales: Apiaceae) fruit on adults of Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae), and its ability to protect stored tobacco leaves from adult L. serricorne infestation were investigated. Essential oil from C. monnieri fruit had potent contact and repellent toxicities against adults of L. serricorne, and the contact and repellent activity increased significantly with increasing exposure time and dose. The greatest corrected mortality of contact toxicity bioassays killed 85.1% at 0.24 µl/cm2 at 72 hours of exposure. The greatest mean percentage repellency in repellent toxicity bioassays killed 93.5% of class V at 0.16 µl/cm2 at 48 hours of exposure. Essential oil of C. monnieri fruit substantially protected packaged flue-cured tobacco leaves from adult L. serricorne infestation. The number of L. serricorne was zero in flue-cured tobacco leaves packaged in kraft paper bags coated with essential oil of C. monnieri fruit at 0.04 µl/cm2 at 45 days. The results suggest that essential oil of C. monnieri fruit is a promising alternative to commonly used insecticides to control L. serricorne. Se investigó el efecto por contacto y la repelencia del aceite esencial de frutos de Cnidium monnieri (L.) Cuss. (Apiales: Apiaceae) en adultos de Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae), así como la posibilidad de proteger hojas de tabaco almacenadas. El aceite esencial tuvo alta toxicidad y repelencia y ambas cualidades incrementaron al aumentar la dosis y el tiempo de exposición. La mayor mortalidad corregida y toxicidad por contacto fue 85.1% con 0.24 µl/cm2 y 72 horas de exposición. La mayor repelencia mató 93.5% de la clase V a 0.16 µl/cm2 y 48 h de exposición. El aceite esencial protegió el tabaco curado de la infestación de adultos de L. serricorne. El número de L. serricorne en hojas de tabaco curado en bolsas fue cero con la concentración de 0.04 µl/cm2 a los 45 días, lo que representa una alternativa a los insecticidas que se usan para el control de la plaga. [ABSTRACT FROM AUTHOR]

This research attempts to fabricate a novel type of pressure‐sensitive adhesive (PSA) tape utilizing epoxidized linseed oil (ELO) as the primary component in an effort to reduce reliance on petrochemical polymers. This raw material comes from the natural renewable resources, making this tape a more environmentally friendly choice in reducing impact on the environment and alleviating resource pressure. The ester groups on ELO are subjected to hydrolysis in order to yield a combination of epoxy linseed oil fatty acids (ELFAs) containing both epoxy and carboxyl groups. By controlling the temperature and catalyst conditions, the epoxy and carboxyl groups undergo a ring‐opening reaction, resulting in the self‐polymerization of the ELFA mixture and the formation of hydroxy‐functionalized polymers. These polymers are then applied as a coating on kraft paper and subsequently cut to produce PSA tapes. The tapes produced using this method exhibit a peak peel strength of 20.538 N per 25 mm. Moreover, the incorporation of glycerol ester of rosin serves to enhance the peel strength, resulting in a higher value of 21.883 N per 25 mm. The utilization of sealing the cardboard box by the tapes also serves as validation for the immense capabilities of the tapes in practical applications. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate) (PHB), a biodegradable polymer, has been studied as a substitute for petroleum-based polymers used for barrier coating to improve the barrier and mechanical properties of paper. In this study, ethyl cellulose (EC), a cellulose derivative, was used to prepare a polymer blend for enhancing the barrier properties of PHB. The prepared PHB/EC blend was then applied as a paper coating material. Additionally, the barrier and mechanical properties of the PHB/EC blend-coated paper based on the PHB/EC mixing ratio and coating weight were analyzed. The results showed that the EC could act as a binder for the PHB/EC blendcoated paper. Consequently, the PHB/EC blend-coated paper exhibited significant improvements in mechanical and barrier properties, including a substantial increase of over 100% in internal bond strength, more than 20% in tensile strength, exceeding 60% enhancement in water resistance, and a remarkable increase of over 90% in air permeability. [ABSTRACT FROM AUTHOR]

The use of alternative insulating liquids instead of mineral oil in transformers is spreading around the world due to their superior fire resistance. Furthermore, researchers have demonstrated that these oils increase the lifespan of the solid insulation of the transformers and, thus, the life expectancy of the equipment. Retrofilling of transformers with natural and synthetic esters allows companies to benefit from the properties of using these liquids without making an investment into new machinery. This paper investigated the ageing process of Kraft paper that was retrofilled with a natural ester in the laboratory. The Kraft paper samples were subjected to accelerated thermal ageing in an oven at 130 °C, and markers such as the degree of polymerisation and tensile strength were measured. The ageing tests comprised a first period, where the samples were immersed in mineral oil, followed by a replacement of the oil with a natural ester. As moisture is a determinant factor for paper ageing, two sets of samples with different moisture contents were tested. The results showed that the retrofilling of the transformers may slow down the degradation rate of the solid insulation despite the presence of remaining mineral oil adsorbed in the paper. [ABSTRACT FROM AUTHOR]

The aim of this research is to predict the mechanical properties along with the behaviors of standard insulating paper used in power transformers under thermal aging. This is conducted by applying an artificial neural network (ANN) trained with a multiple regression model and a particle swarm optimization (MR-PSO) model. The aging of the paper insulation is monitored directly by the tensile strength and the degree of polymerization of the solid insulation and indirectly by chemical markers using 2-furfuraldehyde compound content in oil (2-FAL). A mathematical model is then developed to simulate the mechanical properties (degree of polymerization (DPV) and tensile index (Tidx)) of the aged insulation paper. First, the datasets obtained from experimental results are used to create the MR model, and then the optimizer method PSO is used to optimize its coefficients in order to improve the MR model. Then, an ANN method is trained using the MR-PSO to create a nonlinear correlation between the DPV and the time, temperature, and 2-FAL values. The acquired results are assessed and compared with the experimental data. The model presents almost the same behavior. In particular, it has the capability to accurately simulate the nonlinear property behavior of insulation under thermal aging with an acceptable margin of error. Since the life expectancy of power transformers is directly related to that of the insulating paper, the proposed model can be useful to maintenance planners. [ABSTRACT FROM AUTHOR]

The main objective of this research is to evaluate the influence of coating based on cellulose micro/nanofibrils (CMF) and carboxylated styrene butadiene rubber (XSBR) on sack kraft paper, for possible use in packaging. Filmogenic solutions were applied manually as a coating on sack kraft paper. These solutions were prepared by suspensions of CMF 1.5 % w/v with the addition of different content of XSBR (0, 2, 10, and 20 % about the total mass of CMF). Uncoated sack kraft paper was used as control. Films were obtained by casting and characterized physically, morphologically, and mechanically. The results demonstrated that XSBR and CMF composite suspension showed good performance as a coating on sack kraft paper. The formation of homogeneous structures well distributed on paper can be observed on scanning electron microscope images. Coatings containing XSBR presented a smoother surface, less porosity and hydrophilicity, and a greater coalescence, with good properties of air resistance and water vapor permeability. However, regarding mechanical properties, there were no improvements in coated papers. Therefore, the present study contributed information on the development of more flexible and hydrophobic cellulosic papers for possible applications in the industrial packaging sector. [ABSTRACT FROM AUTHOR]

One of the possible causes of transformer failures is high moisture in the winding insulation system. In an extreme case, when the critical temperature is exceeded, a sudden release of water vapor from the transformer insulation, called the bubble effect, can occur. This article analyzes the initiation temperature of the bubble phenomenon in various solid insulation materials (Kraft cellulose paper and aramid-based high-temperature papers such as Nomex® 910 and Nomex® 926) immersed in two electro-insulating liquids (mineral oil and Midel 7131 synthetic ester). The initiation temperature of the bubble effect depends mainly on the moisture content of the solid insulation, but it was found to be slightly lower for high-temperature materials than for cellulose. However, after taking into account the differences related to uneven water absorption of the tested materials, the differences in the initiation temperature of individual solid materials are very small. Synthetic ester, compared to mineral oil, slightly increases the bubble initiation temperature, regardless of the solid material used. [ABSTRACT FROM AUTHOR]

The effects of cattail/poplar straw weight ratio, sandwich panel thickness, and the number of kraft paper layers at the core of sandwich panels on the modulus of rupture (MOR) of the panels were predicted using an artificial neural network (ANN) and an adaptive neuro-fuzzy inference system (ANFIS). The prediction accuracy of the MOR based on experimental data, in terms of the mean absolute percentage error, was smaller than 1.4 and 1.1%, with coefficients of determination 0.94 and 0.995 for the ANN and ANFIS models, respectively. These models can easily predict the bending strength of lignocellulosic-based sandwich panels with a high precision in the manufacturing process. [ABSTRACT FROM AUTHOR]

Wood-based paper fibers are inherently biodegradable. In contact with moist soil and in compost, papermaking fibers are readily broken down by soil microbes. Resistance to biodegradation is needed, as paper is used for special applications such as mulching in agriculture and forestry, the coating of construction materials, and for packing and wrapping under conditions where packaging materials may be exposed to contact with moist soil or other type microbial active contamination. A preceding study showed that paper chemical crosslinking with glyoxal, citric acid (CA), or methylated 1,3-dimethylol-4,5-dihydroxyethylene urea (mDMDHEU) results in substantially improved paper wet strength and lower paper water absorbency. The present study examined the efficiency of chemical crosslinking treatments with CA and with mDMDHEU to decrease the biodegradation rate of laboratory paper sheets and a sack paper, both made of kraft fibers. The biodegradation was examined using a 48-h enzymatic degradation test and a 2-month soil burial test. The results indicate that chemical crosslinking is an effective non-biocidal method for making sulphate kraft paper more resistant to biodegradation. In some end-uses, improved resistance to biodegradation, along with improved paper wet performance, can enhance paper performance comparable to plastic films. [ABSTRACT FROM AUTHOR]

Corrugated panels possess excellent thermomechanical properties, but, with presently no hygrothermal applications for building envelopes, their full potential still needs to be explored. This study characterized the physical properties of three biobased corrugated compositions to identify potential building applications. Flat samples of the same compositions were analyzed for certain properties to aid in understanding. As this characterization is groundbreaking, the testing was based on or inspired by established standards. Results suggest that the panels with two wood veneer cores and two kraft paper surfaces coated with polymers are the most promising, as such structures are less sensitive to water and possess a good moisture buffer value that should be advantageous for building construction. Corrugated panels are particularly interesting because their inner materials have properties comparable to those of conventional wood-based panels such as plywood. However, the apparent properties of corrugated panels become one to ten times smaller or larger, which opens up new design possibilities for building envelope applications. [ABSTRACT FROM AUTHOR]

The aim of this study is to propose a test method for the determination of the quality of transformer paper insulation. For this purpose, the oil/cellulose insulation systems were exposed to various accelerated aging tests. The results of the aging experiments of normal Kraft and thermally upgraded papers, two different types of transformer oil (mineral and natural ester), and copper are shown. Aging was carried out in various experiments at 150 °C, 160 °C, 170 °C, and 180 °C with dry (initial values ≤ 0.5%) and moistened cellulose insulation (initial values 3–3.5%). Following insulating oil and paper, degradation markers were measured: the degree of polymerization, tensile strength, furan derivates, methanol/ethanol, acidity, interfacial tension, and dissipation factor. It was found that the aging of cellulose insulation in cycles was 1.5–1.6 times faster in comparison to continuous aging, due to the more pronounced effect of hydrolytic mechanism in cyclic aging owing to the produced and absorbed water. Furthermore, it was observed that the high initial water content in cellulose increases the aging rate two to three times more than in the dry experimental setup. The proposed aging test in cycles can be used to achieve faster aging and to compare the quality of different insulating papers. [ABSTRACT FROM AUTHOR]

In this work, we aimed to analyze suspensions of cationic starch by adding 5 wt%, 7 wt%, and 10 wt% of bentonite as a bilayer coating on kraftliner paper (85 g/m2). The controls were doubly-wet-and-dry and uncoated kraftliner paper. In a coating machine, the formulations were applied until reaching a grammage of 15 g/m2 and then dried at 103 ± 2 °C. The test was carried out about pH, solids content, and viscosity of the suspensions. The physical characteristics of the coated papers were evaluated, as well as their ability to block water, water vapor, and oil/grease. We also analyzed with scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy. The packaging, having a water contact angle of up to 78° and 189 g/m² for Cobb, showed a low resistance to water, which is further responsible for decreased mechanical resistance. Nevertheless, the coating did not change the permeability to water vapor, however, bentonite promoted a decrease in wettability and Cobb value of the paper. The addition of 7 wt% bentonite to the cationic starch matrix promoted high oil resistance with 12 for kit-oil, while 10 wt% bentonite promoted greater pencil hardness, with a value of 8H. Bentonite strength and cationic starch showed good interaction, increasing oil resistance. [ABSTRACT FROM AUTHOR]

Literature research revealed that scientific work on the characteristics of historical decorative laminates (DLs), like typology, and particularly the material-technical aspects related to the composition and build-up is scarce in the field of conservation-restoration of modern materials. This paper aims to take the first step towards filling in this knowledge gap by demonstrating that an in-depth literature research and complementary chemical-physical analytical techniques are useful in characterising and contextualising historic decorative laminates. This research focused on gaining additional information within chemical analyses on material-technical insights. This could serve as a basis for a more comprehensive historical context. Several historical samples from different sample-catalogues and museum objects, spanning a period from 1953 to 1993, were collected and their respective cross-sections were characterised with infrared (mapping), FT-Raman, and dispersive micro-Raman spectroscopy. The different layers, such as the protective, decorative, and core layers were investigated, and materials such as melamine formaldehyde, urea formaldehyde, cellulose, lignin, titanium dioxide (rutile), zinc sulphide, synthetic organic pigments PR112 (monoazo pigment, Naphthol AS), and PG8 (azo metal complex, Pigment Green B) were detected. [ABSTRACT FROM AUTHOR]

Cellulosic packaging containing an active and sustainable coating can prolong the shelf-life of cherry tomatoes, maintaining the nutritional composition and physical integrity. A new and sustainable active material packaging was developed based on the silver-impregnated-zeolite incorporation into chitosan Kraft paper coating. Zeolite (NaY) was modified by cation exchange with silver ion (NaY-Ag) and incorporated into a chitosan filmogenic matrix, forming an active coating on the Kraft paper surface. The active coating paper formulation was defined using an experimental design 22 + central points with independent variables: chitosan concentration (1–2%, w/w) and NaY-Ag zeolite concentration (0.2–1.2% w/w). The efficiency of the ethylene scavenger active packaging material was evaluated by packing a perishable fruit (cherry tomato) and conditioning it for 30 days at 25 ± 2 °C. The cherry tomatoes conditioned in active coating paper presented a weight loss reduction of 29% and maintenance of the texture associated with the adsorption capacity of ethylene gas. After 30 days of storage, the a* color parameter increased by 39%, compared to fruits packed in uncoated packages, which increased the a* values by 79%, indicating a slower rate of ripening of cherry tomatoes packed in the active silver-impregnated zeolite NaY chitosan coating on Kraft paper material. The active packaging systems developed showed a tendency to reduce the ripening rate of the fruit, controlling the ethylene concentration in the headspace, and also could contribute to minimizing the impact that synthetic polymer coatings have on paper degradation, presenting a sustainable characteristic. [ABSTRACT FROM AUTHOR]

We describe a wet creping approach, applicable not only for softwood kraft papers in the grammage range of 30–120 g/m2 but also for 300 g/m2 CTMP board. Creping of board requires a certain level of deformability in the material, which is controlled by its solids content. The concept was tested at laboratory scale using a device on which temperature, blade angle and line load could be adjusted. The sample density was decreased by creping due to small-scale delamination of the structure, leading to separate inner layers with a wavy appearance. The strain at break was remarkably increased and agreed well with the theoretical estimate based on the crepe ratio and the breaking strain of the uncreped sample. Simultaneously, tensile strength was reduced by creping. In terms of tensile strength and stretch, 60–70 % solids content during creping was optimal for the tested board. [ABSTRACT FROM AUTHOR]

This article is to study corporate social responsibility through packaging and communicated CSR to evaluate consumer buying decisions using the packaging from coconut fibrin. Packaging was obtained from local materials in the community of Samut Sakorn Province, Thailand. Using local waste material (coconut fibrin) for green packaging, it is beneficial to the environmental issue, and can create jobs in the community by making paper and packaging from coconut fibrin. Coconut pulp paper has performed under alkaline conditions coupling a mixture of natural additives consisting of carboxymethyl cellulose and corn starch. The obtained pulp paper was tested according to The National Standard of Kraft paper. It was characteristic of the liner board. The individual packaging was fabricated and used as an instrument for the consumer perception study (258 informants). We found the consumer view of business doing CSR is an ethical organization (4.44) that deems to present responsibility to society and the environment. The decisions were agreed upon, and consumers were delighted to buy the packaging. The CSR activity through the packaging could induce community development in job creation and reduces waste in the community by adding value to green packaging. The CSR activity of business influences the positive perception of consumers. [ABSTRACT FROM AUTHOR]

[Display omitted] Although thousands of superhydrophobic composites have been reported, it is still a challenge to develop eco-friendly superhydrophobic materials by a simple and low-cost strategy. Here, a paper-based superhydrophobic material was prepared by carbon fiber powders and polydimethylsiloxane through a facile spraying method. This obtained material has excellent liquid resistance and self-cleaning properties, whose contact angle reaches 155°. In addition, it possesses excellent photothermal conversion characteristics with a stable surface temperature of 73.4 °C and good water evaporation performance with an evaporation rate up to 1.08 kg/(m2·h) under one solar intensity (100 mW/cm2). Also, it has outstanding self-deicing performance, whose deicing time is 120 s earlier than that of the untreated surface under one solar intensity. An adaptability test shows this strategy of functional coatings can also be applied to other fiber substrates (coating paper, kraft paper, non-woven fabric, paulownia veneer, etc.). Overall, this superhydrophobic material has a promising application prospect in many fields such as waterproof packaging, deicing materials, water evaporation materials, etc. [ABSTRACT FROM AUTHOR]

Typical scanning electron microscopy (SEM) micrographs obtained for cellulose nanofibrils (a), paper handsheets surface without CNF addition (b) and with 10% CNF (c) Cellulose nanofibrils used as reinforcement go through the fibrillation process in equipment that have discs with grooves on the surfaces against which the pulp is exposed to cyclical and sequential stresses. Preparation of paper handsheets (fiber/CNF) CNF were added directly to the cellulose pulp at 0, 2, 5, 8 and 10 wt% proportion before forming the paper handsheets. Box-plot for tensile index (a), tearing index (b), bursting index (c), stretch (d) and modulus of elasticity (e) in paper handsheets with the addition of different amounts of nanofibrils Figure 6 shows the variations of tensile (a), tearing (b), and bursting (c) indexes, and stretch (d) and modulus of elasticity (e) of cellulose paper handsheets due the addition of different CNF contents. Keywords: Composite fibers; kraft paper; mechanical properties; cellulose microfibrils (CMF); nanocellulose; papermaking; ; ; ; (CMF); ; EN Composite fibers kraft paper mechanical properties cellulose microfibrils (CMF) nanocellulose papermaking ZH (CMF) 7818 7833 16 11/21/22 20221220 NES 221220 GRAPHICAL ABSTRACT Graph Introduction Cellulose nanofibrils (CNF) or cellulose microfibrils (CMF) are known to present unique properties such as high strength and stiffness and to enable numerous applications such as reinforcement material in composites and paper (Osong, Norgren, and Engstrand [21]). [Extracted from the article]

Slaker grits (SG) and biomass fly ash (BFA), two waste streams generated in the pulp and paper industry, are commonly disposed of in landfills, a practice with a high economic and environmental burden. In this work, their individual valorization as fillers in a commercial screed mortar formulation was evaluated in order to achieve a more sustainable management practice. The waste streams were characterized in terms of true density, particle size and morphology, and chemical and mineralogical composition. The influence of their incorporation amount (5.0, 7.5, and 10.0 wt.% of the total solids) and pre-treatment (sieving and grinding) on the fresh (workability) and hardened state (density, water absorption by capillarity, and flexural and compressive strength) properties of the mortars were assessed. The results show that the addition of 10.0 wt.% of the SG after milling and sieving (<75 µm) and 7.5 wt.% of BFA in the as-received condition, or up to 10.0 wt.% after grinding and sieving (<63 µm), allowed for the production of mortar samples with properties within the recommended specifications and that were resistant to 25 consecutive freeze-thaw cycles. This waste valorization route could represent an economic benefit of up to 8.85 €/tmortar and 2.87 €/tmortar for mortar, and pulp and paper companies, respectively. [ABSTRACT FROM AUTHOR]

The microencapsulation of flame retardants can avoid the problems of water absorption and loss. In this paper, hydrophobic microcapsule-encapsulated ammonium polyphosphate (HMAPP) was prepared by ion exchange and Stöber method and applied to the preparation of hydrophobic flame-retardant kraft paper by impregnation. The microscopic morphology and element analysis of the hydrophobic microcapsules tested by TEM and SEM showed that nano-scale particles with a size of about 100 nm have been successfully prepared, and the core–shell structure has been formed. HMAPP constructed a rough structure with low surface energy on the surface of kraft paper and provided the kraft paper with hydrophobic property. The water contact angle of kraft paper reached 122.7 ° after treated by HMAPP, while it also enhanced the physical strength of the paper. Kraft had the self-extinguishing phenomenon after treated by HMAPP, which attached to the surface of kraft paper were heated and melted to release ammonia to dilute combustible gas and oxygen, and formed a flame-retardant layer containing SiO2 particles, phosphoric acid, metaphosphoric acid, pyrophosphoric acid, and carbon flakes on the fiber surface. There were C–C, C–O–C bonds in the carbon layer after flame-retardant treatment, indicating that the pentose contained in fiber has not been completely destroyed. In addition, the presence of Si and P elements in the residual carbon indicates that the decomposed flame retardant adheres to the surface of the fiber to block the heat transfer and flame spread. [ABSTRACT FROM AUTHOR]

Thermal aging and ultraviolet (UV) irradiation are used as methods to prepare samples of kraft paper spanning its full lifecycle within a high-voltage transformer, from new to end of life. The mechanical break strain is correlated with the degree of polymerization (DP), representing a progressive deterioration of mechanical properties during aging. Subsequent exposure to oil flow mimicking both normal plant operation and reclamation activities shows that aged paper exposed to high rates of flow experiences noticeable surface roughening. Despite this, no measurable erosion occurs even after long-term temperature/flow cycling in used mineral oil containing a notable particulate content. This indicates that kraft paper is unlikely to be eroded by normal reclamation activities, even in a severely aged asset. This confirms the validity of using this approach to extend plant life. [ABSTRACT FROM AUTHOR]

Sulfur hexafluoride (SF6) plasma at different pressures, powers, and times was used to treat Kraft paper (KP) to enhance its water resistance. The KP was treated with SF6 plasma from 20–300 mTorr of pressure at powers from 25–75 Watts and treatment times from 1–30 min at 13.56 MHz. The prepared papers were characterized by contact angle measurement and water absorption. The selected optimum condition for the plasma-treated KP was 200 mTorr at 50 Watts for 5 min. Advancement with the change in treatment times (3, 5, and 7 min) on the physical and mechanical properties, water resistance, and morphology of KP with SF6 plasma at 200 mTorr and 50 Watts was evaluated. The changes in the chemical compositions of the plasma-treated papers were analyzed with an XPS analysis. The treatment times of 0, 3, 5, and 7 min revealed fluorine/carbon (F/C) atomic concentration percentages at 0.00/72.70, 40.48/40.97, 40.18/37.95, and 45.72/39.48, respectively. The XPS spectra showed three newly raised peaks at 289.7~289.8, 291.5~291.7, and 293.4~293.6 eV in the 3, 5, and 7 min plasma-treated KPs belonging to the CF, CF2, and CF3 moieties. The 5 min plasma-treated paper promoted a better interaction between the SF6 plasma and the paper yielded by the F atoms. As the treatment time for the treated KPs increased, the contact angle, water absorption time, and Cobb test values increased. However, the thickness and tensile strength did not show remarkable changes. The SEM images revealed that, as the treatment time increased, the surface roughness of the plasma-treated KPs also increased, leading to improved water resistance properties. Overall, the SF6 plasma treatment modified the surface at the nano-layer range, creating super-hydrophobicity surfaces. [ABSTRACT FROM AUTHOR]

This article presents a method for quantification of methanol and ethanol integrated in the same gas-chromatographic run with a quantification of gases dissolved in mineral oil, making it an integrated tool in transformer diagnostics. The results of aging experiments at 120 °C and 60 °C of Kraft paper, copper, barrier, and pressboard immersed in mineral oil, as well as the aging of thermal upgrade paper in mineral and natural ester oil at 140 °C are presented, in order to investigate correlations between different aging markers and to evaluate their partitioning between oil and cellulose at defined conditions. The results of partitioning experiments at 60 °C showed that re-absorption of methanol from oil to the cellulose materials is faster than the re-absorption of furans. This means that methanol is a paper-degradation marker that can be used in diagnostics over shorter equilibrium times and for the detection of developing faults at broader temperature ranges. Furthermore, a statistical overview of methanol concentration from a database and two transformer fault diagnostic cases are presented. Therefore, in addition to an analysis of gases dissolved in oil, the use of methanol and ethanol in transformer fault and failure investigations should be explored and verified through transformer fault investigations and postmortem analyses. [ABSTRACT FROM AUTHOR]

In kraft paper mills, supersonic steam jets are used to remove deposits that build up on the heat exchanger tubes in the recovery boiler. In this study, the fracture toughness KC and work of fracture, WF, of simulated boiler deposits were measured at temperatures up to 500 °C to determine the optimal conditions for deposit removal. The model deposits experienced an important brittle to ductile transition at ~450 °C. Above this temperature, ductile deposits required lower peak force, but four times more energy to fracture when compared to those tested at lower temperatures. The transition was clear in scanning electron micrographs of the fracture surfaces. The findings have significant implications for mills wishing to optimize sootblower performance. [ABSTRACT FROM AUTHOR]

This study measured the decrease in some mechanical properties of kraft paper used in packaging and bag production by examining the colour changes occurring in accordingly prepared standard samples subjected to UV influence. Thus, it is aimed to predict the mechanical properties of packages that have been exposed to sunlight over long periods of time with the colour change measurement, which is a non-destructive test, without the packaging deformation. Since there are mechanical differences between the cross-machine width and machine length of fabricated papers, these were measured separately. Measurements were made on papers exposed to UV for 0, 120, 240, 360, 480, 600, and 720 h. Tensile strength, strain at break, and tensile energy absorption (TEA) values were measured and also predicted for the kraft paper. For the prediction, the time and colour change values were used as independent variables, whereas the mechanical properties were taken as the dependent variables. The relationship between the time and colour change and the tensile strength, strain at break, and TEA variables in both the crossmachine and the machine directions were significant at the 5% level, and the R2 values were within acceptable limits. The results showed that the mechanical properties of the papers under UV effect decreased proportionally with the increase of the UV time. [ABSTRACT FROM AUTHOR]

SB compounds were synthesized from (para, ortho, meta)-phenylenediamine as a cross-linking agent through vanillin. The chemical structure of the formed SB complexes is confirmed by FT-IR spectroscopy. Among the three complexes, para-phenylenediamine (p-SB), possessing a stable resonance structure with the lowest steric repulsion, was obtained in the highest yield of 87%. Hence, the present work focused on reducing the brittle behavior and improving the antimicrobial activity of PLA by reacting it with p-SB. FT-IR investigation revealed the existence of an intermolecular hydrogen bonding between PLA and SB, which led to an increased toughness in the PLA–p-SB complex. This is further confirmed through SEM analysis. The tensile and contact angle measurements determined an improvement in mechanical properties and hydrophobic nature of the PLA–p-SB film. DSC results demonstrated an increase in flexibility, which indicated a 10 °C reduction in glass transition temperature (Tg) of PLA–p-SB films. The antimicrobial activity of the PLA–p-SB films had a maximum of 15 mm zone of inhibition, which was found to be more effective than the neat PLA film. PLA–p-SB coating on Kraft paper showed improved mechanical and barrier properties than neat PLA coatings and could be tried as a possible replacement for conventional synthetic packaging materials. [ABSTRACT FROM AUTHOR]

Effects of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidation were evaluated for magnetic bio-nanocomposites of nanocrystalline cellulose (NCC). The magnetic bio-nanocomposites were prepared using NCC and nanomagnetite (NM) to produce organic compounds. The NCC was oxidized by sodium bromide (NaBr), sodium hypochlorite (NaOCl), and TEMPO. The oxidized NCC (ONCC) was characterized by Fouriertransform infrared spectroscopy (FTIR) and conductometry. The bionanocomposite particles from the NCC and the ONCC were prepared via in situ precipitation of iron salts from alkaline solution. The resultant bionanocomposites were coated on the surface of kraft paper. The magnetic bio-nanocomposite and coated papers were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). The results revealed that the carboxyl groups were introduced successfully on the NCC surface. The bio-nanocomposite particles showed good dispersion in the surface of the papers. The saturation magnetizations of the coated papers with magnetic bio-nanocomposites of NCC and ONCC were 10.9 and 14.57 emu/g, respectively. The magnetic coated papers exhibited a superparamagnetic behavior. The strengths, apparent density, and air resistance of the coated paper with the ONCC bio-nanocomposites increased in comparison to the NCC coated sample, while the water absorption diminished due to the TEMPO-oxidation. [ABSTRACT FROM AUTHOR]

Graphene oxide is one of the latest in- trend nanomaterials in the field of nanotechnology which is being studied in various engineering fields. Yet, its effects on the transformer solid insulation remain unexplored. In this research, the transformer pressboard and Kraft paper are impregnated with nonconductive graphene oxide dispersed vegetable ester-based insulating nanofluid and the behavior of impregnated solid insulation is studied under different thermal aging conditions. The results show that after 60 days of aging, the crystallinity of nanofluid impregnated pressboard is 24.9% more than that of the base oil-blend (OB) impregnated pressboard whereas the crystallinity of nanofluid impregnated Kraft paper is 3.8% more than that of the base OB impregnated Kraft paper. In terms of dielectric properties, the ac breakdown voltage (BDV) of nanofluid impregnated pressboard and Kraft paper is 29.5% and 41% more than the OB impregnated pressboard and Kraft paper, respectively. The dielectric stress is more uniform in nanofluid-based insulation system as compared to the base OB-based insulation system leading to a better design clearance. Therefore, graphene oxide dispersed ester oil (EO)-based nanofluid impregnated solid insulation has better mechanical and dielectric properties, thus leading to an increased lifespan of the transformer. [ABSTRACT FROM AUTHOR]

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

In this study, an optimized method for surface modification of cellulose microfibrils (CMF) with (3-Aminopropyl) trimethoxysilane (APTMS) for eco-friendly hydrophobic coating on kraft paper was achieved using Box-Behnken Design (BBD) through response surface methodology (RSM). Three parameters, including APTMS concentration, hydrolysis-condensation reaction time of APTMS and curing temperature of APTMS, were optimized to obtain the highest water contact angle (θH2O) of the coated kraft paper. The optimal coating conditions extracted by Design Expert Software for the highest value of water contact angle θH2O were APTMS concentration of 8.02% (v/v), APTMS hydrolysis-condensation reaction time of 68.2 min and APTMS curing temperature of 105.3°C. Under these conditions the water contact angle θH2O of 123.3° was obtained. The water contact angle θH2O obtained at these optimal coating conditions experimentally was 124.5°. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), energy dispersive X-Ray (EDX) analysis and scanning electron microscopy (SEM) provided evidence of successful surface silylated of CMF with APTMS. [ABSTRACT FROM AUTHOR]

The purpose of the article is aimed to study an important aspect of the preparation of a theatrical costume - its sketch creation in a set of tasks. In the historical evolvement, the sketch of the costume in the performances of Ukrainian theaters firstly accommodated the commonly used methods of performance. During the years of spreading the theatrical avant-garde, there was a significant step forward in terms of using new materials and textures to form special interpretations of the characters for visual solutions. A striking example of this is Anatoly Petritsky's sketches for two ballets: Corsair (1926) and Red Poppy (1927). Important methods for the study of the chosen topic involve consistent consideration of factual materials in chronological and artistic contexts. The first approach, which is based on the cultural-historical method, makes it possible to establish the main characteristics of the sketch of a theatrical costume within a particular historical period. The historical-comparative method allows comparing the features of approaches to creating sketches in chronological order. The application of the formal method reveals the special approaches of artists to the creation of visual meanings of the characters of the play. The novelty of the study is due to the systematic analysis of the most important parameters of the sketch as a type of work of art, a set of techniques used in the Ukrainian avant-garde theatrical and decorative arts. Conclusions. The analysis of the technological methods traced in the article allows us to state that in the projects of A. Petritsky's performances of the first half of the 1920s mostly established materials and graphic techniques were used. The artist intensified his experiments with textures in the middle of this decade, using drawing and applique to create an individual character, using not only different types of paper but also textiles. [ABSTRACT FROM AUTHOR]

Now days there has been an increase in the consumers demand for great food, produced in environmentally cost-effective and friendly processes, being increasingly necessary new cultivation techniques able to ensure the required standards for banana growers and consumers. Therefore, the research aimed to evaluate the effects of bunch cover materials on development and quality of 'BRS Platina' banana fruits. The experimental design was in randomized blocks, with six treatments, four replications and four plants per plot, being the treatments: WB - without bagging; BBTK - black polypropylene bag (TNT) + kraft paper; BBPK - black polyethilene bag + kraft paper; KP - kraft paper; WBT - non-woven polypropylene white bag (TNT) and WBP - white polyethylene plastic bag. The 'BRS Platina' banana bunches cover improved fruits quality and the treatment polyethylene white bag (WBP) can be an advantageous option for the banana growers because of its effectiveness on the reduction of damages caused by flowers thrips (Frankliniella spp), providing a good agronomic performance and also does not delay the harvesting. [ABSTRACT FROM AUTHOR]

Cellulose fibers' complex and compact structure hinders the quantitative extraction of residual hemicelluloses from the fiber wall. In this study, hardwood kraft paper pulp was subjected to refining with a Hollander beater at different refining loads (3, 4.5, and 5.5 kg) in order to assess the impact of refining load on xylan removal by cold caustic extraction. The refined pulp showed high water retention values and specific surface area, which increased accessibility and a correspondingly high degree of xylan removal. Coupling refining and cold caustic extraction (100 g/L soda) achieved over 50% more xylan removal than the unrefined pulp (3% against 7%, respectively). Furthermore, an improvement in xylan removal (79%) was achieved by implementing a one-pot simultaneous refining and cold caustic extraction treatment at half the time required for the sequential treatment and low soda concentration (60 g/L). Finally, the benefit of beating was also observed for xylanase treatment. Overall, the combined extractions made it possible to remove 85% of xylan from a conventional hardwood paper pulp giving rise to a high purity cellulose pulp with unimodal and narrow molecular mass distribution. [ABSTRACT FROM AUTHOR]

Kraft paper (KP) has the advantages of being biodegradable, recyclable, and environmentally friendly. It has a wide range of applications in paper packaging, food packaging, and other fields. However, the non-waterproof characteristic of KP limits its application in harsh environments or special paper packaging, etc. To solve the problem of poor water resistance of KP, a simple and efficient method is proposed to prepare superhydrophobic coatings on kraft paper (SKP) by spraying method using hydrophobic Nano-calcium carbonate (Nano-CaCO 3) particles and rosin (RA) as raw materials. Here, the micro-nano structures are mainly constructed by hydrophobic Nano-CaCO 3 particles, and RA is utilized as a binder to improve the adhesion between the nanoparticles and the paper. The results indicated that the water contact angle (WCA) of SKP reached 154.5° and the water sliding angle (WSA) was 3.2°. And after 34 h of immersion in water, the WCA of SKP surface can remain above 150°. It can also withstand 30 times of sandpaper abrasion and 30 times of tape peeling. Overall, SKP shows excellent stability, water resistance, stain resistance and self-cleaning. It is expected to protect important documents in harsh environments. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The high-barrier paper packaging was prepared by the solution casting method. • Epichloroghyrin (ECH) was deployed to improve the interfacial interactions. • ECH treatment realized the coating process of hydrophilic polymer on paper. • Coated paper packaging treated by ECH showed high barrier and sealing properties. • The high-barrier paper packaging extended the shelf life of biscuits. The fabrication of coated papers using hydrophilic and biodegradable polymers is important for developing sustainable packaging materials with high barrier and superior mechanical properties. However, water, which is used as the solvent in the paper coating process using hydrophilic polymers, deforms the shape of the paper and deteriorates performance. Therefore, we propose a new coating process that treats Kraft paper (KP) with epichlorohydrin (ECH) as a binder before the coating process. Crosslinked polyvinyl alcohol is coated on the ECH-treated KP using a solution casting method. ECH maintains the shape of the paper and improves coating uniformity; significantly enhances interfacial interactions, which increases barrier properties and sealing strength; and extends the shelf life of biscuits by reducing oxygen and moisture permeability. An ecotoxicity test using Lolium multiflorum demonstrates an insignificant phytotoxicity level for the as-prepared coated papers. Thus, ECH-treated KP is a potential candidate for high-barrier food packaging. [ABSTRACT FROM AUTHOR]

An active chitosan-based coating with an addition of a natural antioxidant and a natural crosslinker has been applied to improve the performance of Kraft paper. Coatings, including chitosan (CS), CS crosslinked with 1.5 % genipin (CS-1.5G), CS containing 1 % astaxanthin (CSA) and CSA crosslinked with 1 % genipin (CSA-1G) were coated on Kraft paper. Uncoated and coated papers were then evaluated for water content (WC), water vapor permeability (WVP), contact angle, oxygen permeability (OP), tensile strength (TS), bursting strength and elongation at break (EAB). Results indicated that the coating improved the properties of Kraft paper. When compared with CS-coated paper, WC and WVP of CSA-1G-coated paper decreased significantly by 40 % and 24 %, respectively. The lowest OP was also observed in CSA-1G-coated paper. CSA- and CSA-1G-coated paper had contact angle values >100°, indicating hydrophobic nature of coated paper surface. All coatings largely improved TS of the paper (by 182–224 %) whereas CS-1.5G and CSA-1G significantly improved the bursting strength of the paper. The developed genipin-crosslinked chitosan-based coating enriched with astaxanthin can improve the functional properties of Kraft paper and thus will facilitate the usage of the paper for food packaging applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Upcycling agroindustry residues into new valuable products is a strategy for mitigating environmental impacts while increasing material circularity. In this study, two sizes of eggshell particles (D 90 = 7.1 μm (ESAJ) and D 90 = 16.3 μm (ESBU)) were obtained and their incorporation as fillers into biodegradable pectin/starch film was evaluated. The effect of the presence of eggshell particles (2–8 w/w%) on the structural and morphological aspects, water barrier, and mechanical, optical, and thermal properties of the biocomposites was evaluated and then the reinforced film was applied on the surface of kraft paper. The release of calcium in an acidic solution was inverse to the size and concentration of particles and the released íon may contribute to the crosslinking of pectin. The incorporation of only 2 % eggshell resulted in 42% lower solubility of the film. The eggshell-reinforced films proved to be more opaque and rigid. The addition of 6% ESAJ significantly improved the tensile strength (an increase of 32%), modulus of elasticity (an increase of 29.7%), and water vapor barrier (59% of improvement). DSC analysis suggests that the calcium from the eggshell interacts with the pectin polymeric structure, reducing the sites available for water molecules, which may have caused more mobility of the chains through the matrix. The reinforced pectin/starch film was very well adhered to the kraft paper in the application test by continuous casting, but the coated paper showed no improvement in oil and water resistance, which means that other coating processes need to be explored. • Eggshell was used as a reinforcing filler material in pectin/starch film. • Eggshell particles were well adhered to the matrix. • The eggshell powder had improved the water resistance of the pectin/starch film. • The addition of 6% eggshell had increased the film's tensile strength in 32%. [ABSTRACT FROM AUTHOR]

This paper presents the prediction of aging state of oil impregnated insulating Kraft paper using textural properties. Under conditions of prolonged thermal stress, the insulating capacity of Kraft paper decreases due to carbonization and degradation of cellulose. To analyze these effects, a new accelerated aging kit is developed for the experiments. Four groups of samples are collected, and the morphology is examined. Texture feature is extracted for the samples using normalization and Gray-Level Co-occurrence Matrix (GLCM). Supervised (Support Vector Machine (SVM)) and unsupervised (K-means) machine intelligence methods are trained to classify images based on the feature. In addition, new samples are checked for feasibility of the prediction of aging state. The calculated training accuracy of SVM is 92.67%, and for k-means is 95.0%, on the other hand, the testing accuracy of SVM is 91.0%, and for k-means is 92.6%. Therefore, this machine intelligence-based methodology using image features is effective in classifying the aging state of the Kraft Insulating Paper. [ABSTRACT FROM AUTHOR]

This paper reports novel comparative study results on the degradation of kraft paper immersed in mineral oil and gas-to-liquid dielectrics under accelerated aging at 120oC and 150oC for duration up to 1344 hours in a controllable oven. Tensile strength and degree of polymerization (DP)v of paper samples before and after aging were measured. Morphological changes were observed using SEM (scanning electron microscope). Degradation of cellulose from kraft paper including its crystallinity change was investigated through EDX (x-ray diffraction) analysis. Thermogravimetric (TG) analysis was used to study the thermal stability of the paper samples aged in the dielectrics. Experimental results showed that DP, and tensile strength of kraft paper decreased with aging. SEM observation indicated that micro globules detected in the aged paper sample and the diameter of micro globules increased with aging time and temperature. The EDX analysis showed that there were increase of crystallinity of aged paper samples. TG analysis showed that higher mass loss was found in aged samples compared to those new one. The initial decomposition temperature slightly reduced with aging time and temperature. [ABSTRACT FROM AUTHOR]

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

Natural esters have the capability to enhance the life expectancy of the insulating cellulose paper used in oil-filled transformers. This work presents the aging behavior of an insulating paper when it is combined with a new natural ester (based on soybean oil) and compared with an industry-proven system according to the latest version of the standard IEEE Std. C57.100 (2011). The temperatures for the candidate system (natural ester + cellulose paper) are 160, 175, and 190 °C. Experimental results show that the average mechanical tensile retention from the industry-proven system aging system is 44.2%, which is used as reference to evaluate the candidate system. According to this investigation, the insulation system with the new natural ester liquid shows an improvement in the behavior of the aging performance compared to the mineral oil system. The Arrhenius life plots demonstrate that the system of natural ester-thermally upgraded Kraft paper shows a life expectancy higher than for the industry-proven system. Therefore, this alternative could be considered either to increase the lifetime of a transformer or to improve its overload capacity during operation. [ABSTRACT FROM AUTHOR]

In the present work, a facile and green synthesis approach for the production of monodispersed, small-sized (2.9 ± 0.7 nm) and stable silver nanoparticles (AgNPs) using soluble soybean polysaccharide (SSPS) was reported. SSPS was used as the reducing and stabilizing agent. The obtained SSPS-stabilized AgNPs (SA) were characterized by UV–vis absorption spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. The antimicrobial activity of the SA colloidal dispersion (SACD) was evaluated based on the growth kinetics of bacteria E. coli and S. aureus. Afterwards, the colloidal dispersion was applied as a coating material to Kraft paper. The SACD-coated Kraft paper exhibited excellent antimicrobial activity against above bacteria strains and P. aeruginosa. The effects of SACD coating on surface wettability, barrier property and microstructure of the Kraft paper were also studied. The results suggested that the SSPS-stabilized AgNPs have great potential in antibacterial applications. Unlabelled Image • A green method was developed to synthesis silver nanoparticles (AgNPs) using soluble soybean polysaccharide (SSPS) as reducing and stabilizing agent. • The synthesized AgNPs were characterized by XRD, TEM, FTIR and EDX. • The SSPS-stabilized AgNPs showed excellent antibacterial property. • The SSPS-stabilized AgNPs have great potential in antibacterial applications. [ABSTRACT FROM AUTHOR]