In recent decades, there has been a steady increase in the global demand for sanitary types of paper (SP), and global competition for this product requires further improvement of its production technology and reduction of its cost. High-quality SP is made from cellulose, mainly from a mixture of long-fiber softwood cellulose and short-fiber hardwood cellulose. Softwood cellulose has higher values ​​of physical and mechanical indicators, but has a higher cost and requires more energy consumption for its grinding than hardwood cellulose. The quality indicators of SP are also affected by the degree of pulp grinding, which leads to an improvement in the mechanical indicators of SP, but intensive grinding of cellulose fibers shortens their average length, which leads to a decrease in capillary absorption, porosity, and air permeability of paper. Therefore, the purpose of the study is to determine the influence of the degree of grinding and the content of hardwood cellulose on the quality indicators of SP in order to determine the optimal composition of its fibrous composition and reduce electricity consumption for grinding softwood cellulose by reducing the degree of its grinding. To obtain SP samples, sulfate bleached softwood and eucalyptus cellulose were used with the addition of polyamideamino-epichlorohydrin resin "Vodamin-115" to the fibrous mass. It is shown that for the degree of grinding of hardwood cellulose within 30–40 o Shopper-Rigler (SR), an increase in its share in the SGP composition leads to a decrease in the breaking force of paper samples in a dry state. For SHP samples in the wet state, the same dependence is observed only for hardwood pulp with a low degree of grinding — 30 оSR, but an increase in the content of hardwood eucalyptus pulp with a degree of grinding of 35–50 оSR contributes to an increase in the strength of the bonds in the SP paper sheet. It is shown that an increase in the degree of grinding of hardwood pulp and an increase in its content in the composition of paper with softwood cellulose leads to a decrease in capillary absorption. It is recommended to grind softwood cellulose to 25 оSR, hardwood cellulose to 35–40 оSR and to use a composition of 30–40 % softwood cellulose and 60–70 % hardwood cellulose with the addition of 18 kg/t of “Vodamin-115” for paper production.

Conductive composites based on nanocellulose, polyvinyl alcohol, and iron, oriented by a magnetic field (Fe-NC-PVA), were fabricated. The study examined the surface morphology, chemical composition, mechanical, and electrical properties of the composites depending on the iron content. It was found that in terms of mechanical strength and electrical resistance, the recommended iron content in the composite varies from 0.13 to 0.25 g. Biodegradable planar bending sensors were made from this material that are characterized by the following parameters: gauge factor – 2–3, reversibility – 98–99

The technologies for processing solid waste of plant raw materials using the example of amaranth stems into cellulose and nanocellulose and the use of nanocellulose in the production of paper and cardboard are analyzed. It is shown that the use of two-stage thermochemical treatment of plant raw materials allows to obtain cellulose with a low residual lignin content and ash content, which is suitable for further chemical processing, in particular for the extraction of nanocellulose from it. Examples of improving the quality of paper and cardboard through the use of nanocellulose from plant waste are given, which allows to reduce wood consumption and reduce the negative impact on the environment.

The work deals with cellulose paper filled with nanocellulose and SrAl2O4:Eu,Dy oxide phosphor. It was found that both nanocellulose and oxide improve the tensile strength of the composites obtained. The samples with the oxide demonstrate a long-lasting photoluminescence (PL) under sunlight and ultra-violet (UV) illumination. Room-temperature the PL spectra reveal a wide multicomponent band spreading over all the visible spectral regions. The short-wavelength part of the band is ascribed to the cellulose-related luminescence, while the long-wavelength PL component with maxima near 540 nm corresponds to the luminescence of the SrAl2O4:Eu,Dy phosphor. The dependency of the PL intensity on oxide concentration suggests the reabsorption of cellulose emission by the oxide and vice versa. The study of the dielectric properties of composite papers shows the presence of dielectric relaxations at low temperatures (T ~−50°C). Similar cellulose materials to those studied can be considered as alternatives for artificial petroleum-based polymers. Low cost, eco-friendliness, biocompatibility, and the simplicity of recycling are among the main advantages of these materials. They are produced from the cellulose which is one of the most abundant renewable materials in nature. The data on the mechanical, dielectric, and optical properties indicate that the papers studied can be used in flexible lighting devices, WLEDs, coating, markers, labels, etc.

Проаналізовано технології переробки твердих відходів рослинної сировини на прикладі стебел амаранту у целюлозу і наноцелюлозу та використання наноцелюлози у виробництві паперу і картону. Показано, що використання двостадійної термохімічної обробки рослинної сировини дозволяє отримати целюлозу з низьким залишковим вмістом лігніну і зольністю, яка придатна для подальшого хімічного перероблення, зокрема для екстракції з неї наноцелюлози. Наведено приклади покращення показників якість паперу і картону за рахунок використання наноцелюлози із відходів рослинної сировини, що дозволяє скоротити споживання деревини та зменшити негативний вплив на довкілля.

The silicon nanowires were produced by a two-step metal-assisted chemical etching (MACE) technique. The surface modification of the SiNWs array with carbon modifiers (fullerene, multiwalled carbon nanotubes, graphene) was carried out by the drop-casting technique. Sensors of physical quantities (temperature, light, and humidity) were obtained on the basis of such hybrid structures. The surface morphology of the modified SiNWs array was investigated by atomic force microscopy. Chemical analysis of the hybrid structures was performed by X-ray diffraction and X-ray fluorescence analysis. The effect of the modification parameters (type and content of the modifier) of the SiNWs array on two different substrates (with a resistivity of 1 and 10 Omega & sdot;cm) on the static and dynamic parameters of such sensors was determined. In particular, the maximum response value for temperature sensors was 22.7 & sdot;103, and the response/recovery time was 0.15/0.74 s, respectively. For the light sensors, the maximum response value was 98, and the response/recovery time was 0.018/0.06 s, respectively. In turn, the maximum response value for humidity sensors was 19, and the response/recovery time was 11.5/3.3 s, respectively. These sensors can be used for complex monitoring of human health and technological processes in industry.

Strain sensors based on nanocellulose (NC) and its composites with polyvinyl alcohol (NC-PVA) have been developed. NC suspension was synthesized using the TEMPO method from reed stalks. PVA aqueous solution was mixed with the NC suspension and dried in a thermochamber. Strain- sensitive film Cr/Ni was deposited using magnetron sputtering technique onto the surface of NC, PVA, NC-PVA, and also on the reference material of polyimide (PI). To evaluate the efficiency of the strain sensors the electrical characteristic under bending were studied. It has been demonstrated that the parameters of strain sensors are depended on the type of substrate. The maximum strain sensitivity of sensors (2.48) was observed for nanocellulose-based substrates. However, these sensors are slightly worse in terms of time drift and reversibility compared to sensors on other substrates. The potential application of such sensors for analyzing movements of upper and lower limbs, facial muscles, speech recognition, and handwriting recognition has been shown.

This work was aimed on preparation and study of paper embedded with SrAl2O4:Eu,Dy oxide, carbon nanotubes and nanocellulose. The first type of filler is known long-lasting and mechanoluminescent phosphor and the second one - as modifier of mechanical and optical properties of the paper composites. Nanocellulose was also added to improve the mechanical properties of the composites. The physical (mechanical, dielectrical, and optical) properties of composite samples engineering was performed by changing fillers content. The mechanical, dielectrical, and optical properties were studied and analyzed from viewpoint of the fillers influence on composites characteristics.

The paper is devoted to studying the influence of the configuration of the tenso-sensitive element on the characteristics of bend sensors manufactured on the basis of nanocellulose (NC) and polyvinyl alcohol (PVA) composites. For this purpose, a suspension of NC was extracted during the oxidation of organosolvent cane cellulose in the medium of reagent 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Nanocellulose-based composite materials were obtained by mixing the NC suspension and PVA aqueous solution and vacuuming. The films were produced by pouring the mixture into Petri dishes and drying them in a thermal chamber. Technological masks were manufactured from magnetic material using photochemical etching to set different configurations for the tenso-resistors (U-, Π-, UU-, and ΠΠ-type). A metal strain-sensing element (Ti-Ni) was deposited on the surface of films by reactive magnetron sputtering in the argon medium. The atomic force microscopy (AFM) studied the surface morphology of different substrates. The strain-sensitive characteristics of bend sensors were measured, based on which the coefficients of strain-sensitivity, reversibility, and time drift were calculated. It has been established that the maximum value of strain sensitivity (16.19) occurs for sensors based on the NC–PVA composite with Π-type configuration. At the same time, the best reversibility (0.09

There is a steady trend in the world to increase the production of packaging cardboard and paper materials, in particular moisture-resistant container cardboard, which is intended for packaging chilled and frozen products. At the same time, the technology for producing moisture-resistant container cardboard uses chemical additives (CDA), which are usually synthesized from exhaustible energy sources (oil, gas, coal), which pollute the environment and harm human health. An alternative to environmentally harmful CDA are natural biodegradable materials, which include nanocellulose (NC). NC has unique properties and great potential for application in various industries, in particular for improving the performance of paper and cardboard. The paper presents the results of research into the processes of obtaining cellulose and nanocellulose from sunflower stems and the influence of nanocellulose on the quality indicators of moisture-resistant cardboard. The chemical composition and morphological structure of the woody part and parenchyma of sunflower stems were determined. Changes in the yield, residual lignin content and mineral substances in cellulose during the thermochemical treatment of sunflower stalks by extraction with alkali and peracetic solution are presented. The influence of technological parameters of the process of hydrolysis of organosolvent sunflower cellulose on the quality indicators of nanocellulose (NC) is studied. It was established that sunflower NC particles have a transverse size of 6–20 nm, a length of tens of micrometers, the NC suspension has a density of up to 1.51 g/cm³, and NC films have a tensile strength of up to 65.4 MPa, transparency of up to 83%, a crystallinity index of up to 78.4% and a lateral order index of up to 1.83. The influence of sunflower NC on the quality indicators of moisture-resistant container cardboard is studied. It has been established that increasing the consumption of NC in the range from 1 to 5 kg/t of cardboard has a positive effect on its quality indicators, in particular on mechanical strength and water resistance. The use of sunflower NC in the composition of moisture-resistant cardboard allows replacing 50% of environmentally harmful synthetic chemical auxiliary substances used in the production of paper and cardboard.

An urgent scientific and practical task for electrical engineering enterprises is to improve the specific characteristics of component transformers and capacitors that use electrical insulating paper. Electrical insulating paper is characterized by a wide list of special quality indicators, the necessary values ​​of which are achieved due to the use of cellulose with special properties and various chemical auxiliary substances. There are known attempts to use nanocellulose (NC) from wood to reduce the consumption of harmful synthetic chemical auxiliaries, but there are practically no research results on the impact of consumption of NC from non-wood plant materials. Therefore, in the work, a comparative study of the effect of NC from hemp fibers and coniferous wood on the target indicators of the quality of electrical insulating paper was carried out. For this, cellulose, suitable for extracting NC from hemp fibers, was obtained by an environmentally safe organosolv method. NC is obtained as a result of acid hydrolysis of organosolv hemp and sulfate unbleached coniferous cellulose, which is traditionally used in the production of electrical insulating paper. Laboratory samples of electrical insulating paper were made with a weight of 65±3 g/m2 from sulfated unbleached coniferous cellulose with the addition from 1% to 5% NC by weight of paper. The research results confirmed the hypothesis that the addition of NC paper pulp from various plant raw materials leads to an increase in the mechanical and electrical strength of the paper. It has been established that the effect of NC from hemp fibers on the quality indicators of electrical insulation paper is not inferior to the effect on them of NC from coniferous wood, and in some cases even a better result is observed. It was established that the introduction of NC into the composition of paper practically does not reduce its degree of polymerization, which is of great importance for maintaining high reliability and a long duration of work of paper insulation. The obtained results have scientific and practical significance for other types of insulating papers: capacitor, cable, telephone, impregnation, transformer, etc.

Introduction. Currently, artifi cial polymers that pollute the environment are used in bend sensors. Nanocellulose (NC) is a biodegradable and flexible material, but it has a low elongation ability, which limits its use for human motion detection. Creating NC-based composites is a way to solve this problem. Problem Statement. Synthesizing bend sensors based on biodegradable material (bionanocomposite of nanocellulose (NC) and polyvinyl alcohol (PVA))) to be used in sensors for analyzing human muscle activity is an urgent problem. Purpose. To determine the effect of the sensor substrate material on the operating parameters of bend sensors. Materials and Methods. The synthesis methods have been as follows: acid hydrolysis of organosolvent cellulose to obtain NC, vacuum casting to obtain NC-PVC nanocomposite films, and high-frequency magnetron sputtering to produce strain-sensitive films. The following research methods have been employed: optical spectrometry, mechanical elongation and tensile testing, souil burial degradation test, and strain measurement. Results. NC-PVC composites have been synthesized and bend sensors have been created on their basis. The main electrical parameters of the obtained bend sensors are as follows: the strain sensitivity coefficient is 7.52, the reversibility ranges within 9-23%, the time drift varies within 0.17-0.5%/min. The biodegradability of the composite is 21-70% mass loss in 4.5 months. The effect of the sensor substrate material on the functional properties of these sensors has been investigated. It has been found that the addition of PVA to NC improves the optical and mechanical properties of the composites. Conclusions. The optimal composition of the composite can be considered a mix of NC-PVC in a ratio of 1: 1. The developed bend sensors can be used to monitor human muscle activity for medicine, sports, and rehabilitation.

In this work, cotton fabric (Ct) impregnated with nanocellulose (NC) was used to create an environmentally friendly, biocompatible and biodegradable elastic and water-repellent smart textile. For its manufacture, an inexpensive nanocellulose hydrogel was obtained by the method of TEMPO-mediated oxidation of an organosolv pulp from stalks of non-wood widespread wild-growing perennial cereal common reed. Then, an 8 µm thick nanostructured layer of promising non-toxic and earth-abundant copper(I) iodide (CuI) thermoelectric semiconductor was deposited by the Successive Ionic Layer Adsorption and Reaction (SILAR) chemical solution method on the composite Ct/NC fabric. Thus, a smart Ct/NC/CuI thermoelectric textile was obtained. Studies of the crystal structure by X-ray diffractometry (XRD), chemical composition by X-ray fluorescence (XRF) microanalysis and energy-dispersive X-ray spectrometry (EDS), and surface morphology by scanning electron microscopy (SEM) confirmed high adhesion of NC to Ct, good absorption of NC by cotton fiber, and penetration of NC into the inner part of Ct fiber, which is important for strengthening and hydrophobization of cotton. Experimental measurements of the thermoelectric parameters of Ct/NC/CuI textile revealed a Seebeck coefficient of 115 μV/K, a conductivity of 4.96 S/cm, a thermoelectric power factor at near room temperatures of 6.56 μW/(m K2), and a specific thermoelectric power 4.5 µW/cm2. These indicators of thermoelectric efficiency allow the Ct/NC/CuI textile obtained here to become the basis for an efficient body-heat-harvesting thermoelectric nanogenerator.

Стаття присвячена дослідженням впливу наноцелюлози (НЦ) із різної рослинної сировини – волокон конопель (ВК) і хвойної деревини (ХД) на показники якості електроізоляційного паперу. Встановлено, що витрата НЦ від 1 % до 5 % від маси паперу позитивно впливають на показники його якості, що сприяє вирішенню технологічних питань щодо досягнення вимог стандартів. Доведено зростання механічної і електричної міцності паперу та збереження їх значень після проведення термічного старіння. Показано, що введення НЦ у композицію маси призводить до незначного зростання тангенсу кута діелектричних втрат електроізоляційного паперу та його зростання в процесі термічного старіння паперу. Встановлено, що вплив НЦ із ВК на показники якості електроізоляційного паперу не поступається дії на них НЦ із ХД. Підтверджено суттєве збільшення значень діелектричної проникності та незначне зростання рН і зниження електропровідності водної витяжки паперу з додаванням НЦ у волокнисту масу. Показано, що введення НЦ у композицію паперу практично не знижує його ступінь полімеризації, що має практичне значення для підтримання високої надійності та довгої тривалості роботи паперової ізоляції.

Стаття присвячена процесу вилучення целюлози із стебел очерету екологічно безпечним органосольвентним способом делігніфікації, одержанню з неї наноцелюлози кислотним гідролізом і дослідженню впливу наноцелюлози на показники якості паперу-основи для шпалер. Термохімічна обробка стебел очерету проведена у дві стадії – лужна екстракція та органосольвентне варіння, що дозволяє отримати целюлозу, придатну для одержання наноцелюлози. В результаті процесу гідролізу органосольвентної целюлози екстраговано стабільну у часі суспензію наноцелюлози із частинками діаметром 5-25 нм, із щільністю до 1,52 г/см3, прозорістю до 81,6 %, міцністю на розрив до 65 МПа. Показано, що використання наноцелюлози з витратою до 1 % від маси паперу призводить до суттєвого покращення фізико-механічних показників якості паперу-основи для шпалер. Встановлено, що заміна 50% синтетичної хімічної допоміжної речовини алкіл кетен димеру на наноцелюлозу або додатковим нанесенням наноцелюлози з витратою 0,5 г/м2 на поверхню відливки з 0,7 % алкіл кетен димером дозволяє отримати папір, який задовольняє вимогам стандарту.

In this work, a conductive composite based on nanocellulose, polyvinyl alcohol, and graphite (NC-PVA-C) was fabricated. Investigation of the surface morphology, chemical composition, mechanical properties, electrical, and piezoresistive characteristics depending on the content of graphite in the composite was conducted. In terms of mechanical strength and electrical resistivity, the optimal graphite content in the composite ranges from 50% m/m to 85% m/m. However, in terms of piezoresistivity and biodegradability, a graphite content of 85% m/m in the composite is the most preferable. Such composite is characterized by the following parameters: resistivity - 200 Ohm*m, full degradation time in the soil - 1 month. The obtained sensors were successfully applied to investigation of human muscle activity (movements of upper and lower limbs, recognition of pronunciation of sounds and symbols in writing).

Improving the production technology of products with improved quality indicators and with less impact on the environment remains an urgent scientific and practical problem of paper industry enterprises. This refers to the technology for the production of paper-bases for wallpaper using environmentally safe chemical additives, in particular nanocellulose (NC), which was obtained by acid hydrolysis from reed cellulose. The production of cellulose was carried out in two stages - extraction from reed stalks with a solution of alkali and an organosolvent method of cooking in a solution of peracetic acid. The obtained organosolvent cellulose contained the remains of lignin and mineral substances, which allows it to be used for the preparation of NC. As a result of the hydrolysis of organosolvent cellulose, a time-stable NC suspension was extracted, the properties of which were investigated by scanning electron microscopy (morphological changes in the structure of reed cellulose-containing materials), atomic force microscopy (determination of topographic characteristics of NC), analysis of electronic absorption spectra (transparency of NC films). It was established that reed NC films had nanoparticles with a cross-sectional size of 5-25 nm, density up to 1.52 g/cm3, transparency up to 81.6 %, tensile strength up to 65 MPa. For the production of castings of paper-bases for wallpaper samples, sulfated pine bleached cellulose and polyester synthetic fiber were used, to the fibrous mass of which were added the following chemical additives: alkyl ketene dimer, reed NC, binder, and optical brightener. It has been shown that the use of nanocellulose at a rate of 0.35 % to 1.0 % of the paper mass leads to a significant improvement in the physical and mechanical quality indicators of the paper base for wallpaper. It was established that the replacement of 50 % of the synthetic chemical auxiliary substance alkyl ketene dimer with nanocellulose or additional application of nanocellulose at a rate of 0.5 g/m2 on the surface of the casting with 0.7 % alkyl ketene dimer allows to obtain paper that meets the requirements of the standard. The obtained results indicate the prospects of using reed nanocellulose for the production of other mass types of paper and cardboard.

Introduction. The measurement of relative air humidity plays a crucial role in various aspects of human life, such as climate control systems, medical breath and skin hydration monitoring. Typically, humidity sensors use inorganic materials and petroleum-derived polymers. However, there is a growing trend towards the transition to biodegradable materials, which eliminates the need for waste disposal.Problem Statement. Currently, nanocellulose (NC) has been being explored as a promising material for humidity sensors. However, the influence of the chemical composition and nanoparticle size of NC on the sensor characteristics remains understudied.Purpose. This study aims to investigate the influence of the chemical composition and structure of NC on the parameters of humidity sensors.Materials and Methods. NC has been synthesized from reed stalks and wheat straw bz the oxidation and acid hydrolysis methods. NC-film sensors having a mass within 0.3—3 mg have been fabricated. The static parameters (response, sensitivity, reversibility, and repeatability) and the dynamic parameters (short and long-term stability, response and recovery time) of the sensors have been analyzed.Results. The manufacturing method influences the NC chemical composition, while the origin material affects its structure. The sensors produced by the oxidation method have demonstrated improved sensitivity (2.69 · 106), response (0.2 (%RH)–1), recovery time (60 s) and long-term stability (1.44%) as compared with those made by the hydrolysis method. Additionally, the application of wheat straw NC as origin material has resulted in improved reversibility (5%), repeatability (5% deviation), short-term stability (30% deviation), and response time (1 s) as compared with the reed stalks NC.Conclusions. It has been established that the origin material of nanocellulose influences the reversibility, repeatability, response time, and short-term stability of the sensors. The manufacturing method has effect on the sensitivity, response, recovery time, and long-term stability of the sensors.

The study describes the production of pulp and nanocellulose (NC) from non-wood plant materials (NWPM) and use it in the composition of paper and cardboard. For the production of nanocellulose, various representatives of NWPM were used—hemp fibers, reed stalks and corn harvest residues. Pulp was obtained from NWPM by an environmentally friendly organosolv method using a peracetic acid solution. Nanocellulose was extracted from organosolv pulp (OP) by acid hydrolysis or by oxidation in 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) solution. Nanosizes of obtained NCs were confirmed by AFM method. The nanoparticles of NCs have a transverse size in the range of 3–18 nm and a length of tens of micrometers, a density in the range of 1.25–1.54 g/cm3, a tensile strength in the range of 43–67 MPa, a transparency in the range of 57–85

Nanocellulose was made in the form of water gel using chemical and ultrasound treatments of the Miscanthus x giganteus plant. Properties both of nanogel and of its thin solid films deposited on glass, silicon and microcrystalline cellulose substrates were studied. Nondestructive methods (XRD, viscosymetry, scanning electron and optical microscopy, reflection and luminescence spectroscopy) were used to characterize studied materials. The results obtained allowed estimation of nanofibrils sizes both in water solutions and in the solid states. It was found that the aspect ratio for the nanofibrils (p = l/d, where l is the length and d - diameter) in the nanogel state decreases from 130 to 20, when temperature increases from 15 to 75 & DEG;C. The value of p for nanofibrils in solid films is in the range of 3-30. It was assumed that mentioned data are the result of aggregation of the nanofibrils in the solid state and under water nanocellulose gel cooling. The data about optical properties of the nanocellulose under study showed that optical reflection and photoluminescence methods are suitable, in principle, for characterization of nanocellulose made from Miscanthus x giganteus in the form of nanogel, too.