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Nanocellulose (NC) is a promising modern material suitable for use in electronics. This material is biodegradable, and thus, if used in electronic devices, will not require disposal and will decompose naturally. An interesting feature of nanocellulose is its hygroscopicity, which makes it applicable for the manufacture of humidity sensors. In this study, we synthesized nanocellulose-based humidity sensors with a weight of humidity-sensitive layer from 0.3 to 3.6 mg. The following static and dynamic characteristics of the obtained sensors were measured: sensitivity, response, hysteresis, repeatability, response and recovery time, short and long-term stability. It was determined that at a frequency of 100 Hz, the maximum sensitivity was observed in the sample with NC mass of 1.8 mg (0.215 (%RH)–1), and at 1000 Hz, in the sample with NC mass of 0.5 mg (0.155 (%RH)–1). Thus, with increasing frequency of test signal, the sensitivity of the sensors decreases. These same samples (with NC mass of 1.8 mg at 100 Hz and 0.5 mg at 1000 Hz) showed the highest values of sensor response — 1.99‧106 and 5.43‧104, respectively. Same as with sensitivity, when frequency increases, sensor response decreases. For both frequencies, the sample with NC mass of 0.4 mg showed the lowest value of hysteresis — 0.04 and 0.12% at 100 and 1000 Hz, respectively. It was also found that the sample with NC mass of 0.3 mg has the shortest response time of 42 s. With increasing of NC weight, the response time increases about 20-fold and recovery time — by 2 orders of magnitude. The highest short-term stability was demonstrated by the sample with NC weight of 0.5 mg: deviations from the arithmetic mean were 8 and 7.8% at test frequencies of 100 and 1000 Hz, respectively. The worst short-term stability was demonstrated by the sample with NC mass of 3.3 mg with the deviation of 31.7 and 39.2% at the same frequencies. It was also determined that such sensors need to be further researched to improve long-term stability. Therefore, the measurement results demonstrate that, in terms of sensitivity and response, the optimal mass of NC film is 1.8 mg at the test frequency of 100 Hz. This sample also shows the best long-term stability. From the point of view of recoverability and sensor speed, the sample with NC weight of 0.3—0.5 mg is preferable.

Owing to the rapid development of wearable electronics and smart textiles, demands for flexible and wearable thermoelectric (TE) devices, which can generate electricity in a ubiquitous, unintermittent and noiseless way for on-body applications are growing rapidly. Due to the inherent flexibility and wearability features, textile-based thermoelectric generators (TEGs) possess significant potential for biomedical and consumer health and safety applications. In this study, using commercial cotton fabric, we created efficient thermoelectric (TE) textile that, unlike analogs, is based on thin-film composite of biocompatible semiconductor copper iodide (CuI) and biodegradable polymer nanocellulose (NCp) obtained by processing a widespread plant common reed. The CuI films with average thickness 10 µm were deposited via low-temperature aqueous cheap, facile, and scalable fabrication technique Successive Ionic Layer Adsorption and Reaction (SILAR). The NCp sublayer made it possible to fabricate thin-film ohmic contacts through vacuum deposition of chromium on the nanostructured CuI film in the TE textile. The topping of CuI film with NCp layer improved durability and wear resistance of the wearable thermoelectric module fabricated with this TE textile. The developed TE module has shown output power density 44 µW/cm2 at temperature gradient 50 K that is among the best currently known results for solid miniature flexible and fabric-based TEGs.

Inexpensive biodegradable and biocompatible materials, which enable a combination of high hydrophobicity with good adhesion of water droplets, as on rose petals, are in demand for modern microfluidic systems. To obtain surfaces with rose petal-effect we used nanocellulose as bio-based non-toxic material with nanoscale structure. Two types of lightweight flexible nanocellulose films were investigated, differing in raw material and manufacturing method, NCm from Miscanthus x giganteus and NCp from Phragmites australis. They were coated with semiconductor cuprous iodide (CuI) films using Successive Ionic Layer Adsorption and Reaction method, thereby creating hierarchical structures. The deposition of CuI films increased roughness of the NCp and NCm surfaces and ensured high hydrophobicity of the obtained CuI/NCp and CuI/NCm film samples due to chemical modification of nanocellulose. These samples have water contact angles 143°, and large wetting hysteresis above 80°. The water droplets sticking on them testify to the Cassie-impregnating state. On the inclined surfaces of the CuI/NCp and CuI/NCm film samples water droplets do not roll down even if tilt angles reach 90°. So, in this study, we report a facile process for making green, renewable, and biodegradable material with surface functionalities that are relevant for lab-on-a-chip microfluidic devices.

In this work we present utilization of solar energy for a creation of biocompatible, biodegradable, and renewable thin film transparent materials that can protect against overabundant ultraviolet (UV) radiation and high energy visible (HEV) light of solar spectrum. From biomass of herbaceous plants Miscanthus × giganteus and Phragmites australis we obtained nanocellulose suspensions NCm through acid hydrolysis and NCp through TEMPO oxidation, respectively. These suspensions transformed into corresponding transparent flexible NCm and NCp nanocellulose films and used as substrates for 0.17 – 0.23 µm thick nanostructured layers of wide band gap semiconductor CuI deposited via wet chemical method Successive Ionic Layer Adsorption and Reaction (SILAR) to obtain promising visibly transparent UV- and HEV-shielding materials CuI/NCm and CuI/NCp. Under this investigation, we compare UV- and HEV-shielding properties of transparent NCm, CuI/NCm, NCp, and CuI/NCp flexible samples depending on structure, surface morphology, chemical composition, optical properties, and thickness. It is shown that the best CuI/NCp sample with 0.23 µm thick CuI film and 8 µm thick NCp substrate has optical transmittance up to 82% for visible light at wavelengths above 500 nm, blocks 65% of high-energy visible radiation, and has excellent sun protection factor (SPF = 112).

"The main goal of the study was to investigate processing of Miscanthus x giganteus biomass produced in soil contaminated with lead and other trace elements (TEs) into pulp using chemical pulping. The phytoremediation parameters of the plant were measured during two growing seasons, which confirmed that the process can be defined as phytostabilization; the contaminants were mainly concentrated in the roots and practically did not translocate to the stalks and leaves, which permitted the use of the aboveground biomass to process into pulp using the organosolvent cooking. The chemical composition, morphological structure, and microscopic characteristics of various crops’ stalks were investigated and compared with the same parameters received for wood and other non-wood plant materials: rape, flax, hemp, and wheat straw. Indicators of pulp were studied depending on the duration of the organosolvent cooking. After 90 minutes of the cooking process, the peroxide pulp from M. x giganteus had a breaking length of 8300 m, tear resistance of 310 mN, and burst resistance of 220 kPa, testifying the high values of the indicators. Further research should investigate the properties of pulp produced from M. x giganteus biomass grown in soils contaminated with various TEs, as well as the possible translocation of elements to pulp."

Renewable plant materials are of interest for the development of new biodegradable materials. The study describes the preparation process of nanocellulose from organosolv reed pulp (ORP). ORP was obtained from reed stalks in two stages: by extraction of the raw material with NaOH solution and cooking using a mixture of acetic acid and hydrogen peroxide. Nanocellulose was extracted from ORP using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in a TEMPO/NaBr/NaClO system followed by ultrasonic treatment to obtain a stable nanocellulose gel. It was found that an increase in the TEMPO consumption and oxidation time increases the density and tensile strength, the content of carboxyl groups, and the transparency of the nanocellulose films, but decreases the yield and crystallinity of the nanocellulose. Structural and chemical changes and the crystallinity index of reed stalks, ORP, and nanocellulose were studied using SEM, FTIR, and XRD methods. Nanocellulose films had a density of up to 1.51 g/cm3, a transparency of up to 82.4%, a carboxyl group content of up to 1.18 mmol/g, and a tensile strength of up to 69.7 MPa. The crystallinity index of nanocellulose decreases from 78.8 to 64.9% with an increase in the oxidation time. TEM and AFM methods have shown that the width of nanocellulose particles is from 3 to 20 nm. TGA confirmed a decrease in the crystallinity index of nanocellulose as a result of its prolonged oxidation. The properties of the obtained nanocellulose from ORP demonstrate the great potential of its application for the preparation of new nanocomposite materials.

Nanostructured cuprous iodide (CuI) thin films obtained via cheap, affordable, and suitable for mass production aqueous method Successive Ionic Layer Adsorption and Reaction (SILAR) on flexible bio...

Here we applied solar energy converted into biomass to produce efficient biodegradable flexible hydrophobic thermoelectric (TE) material with nanocellulose (NC) film as environmentally friendly functional substrate. We used fast-growing perennial herb Miscanthus × giganteus to manufacture flexible 12 µm thick NC film with stable monoclinic cellulose structure (Iβ), high crystallinity index (CI = 78%) and average crystallite size 3 – 4 nm. Through the low-temperature cheap and scalable method Successive Ionic Layer Adsorption and Reaction (SILAR) we deposited copper iodide (CuI) films on NC substrates and thus obtained non-toxic TE materials CuI/NC, which can be water-repellent, as their contact angles reach 140°. In the most efficient TE sample CuI/NC, the obtained via SILAR 0.39 µm thick nanostructured CuI film consists of cubic (1 1 1)-oriented γ-CuI crystals with faceted surfaces of ~200–300 nm. The high electrical conductivity (σ) and shape of the σ vs. temperature (T) curve of this CuI/NC sample is realized through suppression of grain boundary scattering due to tunneling currents in CuI. The CuI/NC material has large thermoelectric power factor (PF) that grows with increasing temperature and reaches value 140 μW·m−1·K−2 at T = 333 K. This PF is the record for biodegradable flexible thermoelectric materials. At ΔT = 40 K the CuI/NC-based single p-CuI thermoelectric leg generates open circuit voltage 3.5 mV, short circuit current 4 µA, and power 3.8 nW, and these output parameters can be further improved through a thickening the CuI film in CuI/NC by increasing the number of SILAR cycles.

Background: The technological developments for nanocellulose production from cheaper plant materials compared to wood, in particular, agricultural waste is an urgent task of nanobiophysics. The discovery of possibility of expanding the functional characteristics of materials in compositions with modified cellulose particles essentially stimulated the interest of researchers in cellulose composites. Surface modification of cellulose particles by functional materials, such as dyes, metal oxides, silicon, allows applying composites with modified cellulose in various areas of modern industry. A significant improvement in the operational performances of functionalized cellulose particles can be achieved by using them as filler in polymers. Epoxy resin compositions with modified and unmodified cellulose particles, studied in present work, are an example of hybrid biosystem. The interfacial interaction of filler particles with the epoxy matrix, their concentration and dispersion can change the physical and chemical properties of the biopolymer and the functional parameters of biocomposites. Studying the influence of external fields on the physical and chemical properties of epoxy resin-based biosystems and their influence on operational parameters seems to be an urgent problem of advanced and sustained materials science. Objectives: The purpose of this work was to develop an effective nanocellulose synthesis from plant materials and surface functionalization of micro- and nanocellulose particles with clathrochelate iron (ΙΙ) dye as well obtaining biocompositions of epoxy resin with functionalized and non-functionalized micro- and nanocellulose, and to explore of the morphology, chemical resistance, mechanical and thermal properties of epoxy composites with cellulose micro and nanoparticles. Materials and methods: The studying objects were the composites of epoxy resin Eposir-7120 with a polyethylene polyamine “PEPA” hardener in a ratio of 6.2:1 and 10% cellulose micro and nanoparticles. The microcellulose obtained from wood has been a commercial product. Nanocellulose has been synthesized from organosolv cellulose obtained from Miscanthus x giganteus stalks. Surface modification of micro- and nanocellulose was performed using the clathrochelate iron (ΙΙ) dye. The specific surface area of cellulose particles was determined using low-temperature nitrogen adsorption-desorption according to the Brunauer-Emmett-Teller method. Mechanical parameters were determined using universal Shopper and UMM-10 machines. Thermal analysis was performed using Q1500 analyzer. Swelling was determined by the gravimetric method. Results: Elastic modulus E, compressive strength σ and thermogravimetric parameters were determined. It was shown that in composites with micro and nanocellulose the E rises in 7.0–12.2% while the σ increases in 9.1% for composites with cellulose micro particles. The loading resin with nanocellulose and modified cellulose microparticles no affects the σ value of composites. The thermal stability of epoxy polymer (310°C) reduces after loading with micro and nanocellulose to 290 and 300°C, respectively. Chemical resistance of composites with both celluloses to 20% nitric acid reduces. In neutral medium swelling characterizes by rapid sorption to saturation of 15–20% acetone in 36 hours. Conclusions: Thus, the synthesis method of nanocellulose from plant materials and functionalization of its surface with clathrochelate iron (ΙΙ) were developed. Light response of dye was detected in visible spectral range. Epoxy resin composites with 10% micro and nanocellulose were obtained. The filling effect with micro- and nanocellulose at elastic modulus, compressive strength, and thermal stability of epoxycomposites was studied. The swelling processes run similarly in composites with cellulose micro and nanoparticles.

In this work, we used solar energy converted via photosynthesis into chemical energy of the biomass of the fast-growing perennial herb Miscanthus × giganteus for the manufacture of nanocellulose (NC) films, which are biodegradable alternative to common petroleum-based polymer substrates used in flexible electronics. To create the NC substrates, we applied an environmentally friendly method of organosolv delignification of plant raw materials carried out at a low temperature and in a relatively short time. Then by means of the low-temperature cheap and scalable method Successive Ionic Layer Adsorption and Reaction (SILAR) we deposited copper iodide (CuI) film of 0.72 µm thickness on both sides of the 12 µm thick NC substrate, and thus obtained light-weight and flexible biodegradable nontoxic thermoelectric material CuI/NC. Crystal structure, morphology, chemical composition, and optical, electrical and thermoelectric properties of the CuI/NC have been researched. Studies have shown that nanostructured p-type semiconductor CuI film in the CuI/NC TE material is quite dense and completely covers the NC surface. It has typical optical direct band gap ≈ 3.0 eV, is single-phase γ-CuI with crystallite sizes in the 19–25 nm range, with moderate dislocation density of (1.6–2.8) × 1015 lines/m2, and tolerable microstrains e of (4–9) × 10−3 a.u. The determined value of the Seebeck coefficient S is ~228 μV K−1, at that, S is constant in the temperature range 290–335 K. Together with the thermoelectric power factor ≈ 36 μW·m−1·K−2it is favorable for the use of CuI/NC as new thermoelectric material for an in-plane design of biodegradable flexible thin film thermoelectric generator (TEG). At temperature gradient of 50 K, the single p-CuI thermoelectric leg made from CuI/NC strip of 3 cm long and 0.5 cm wide generates open circuit voltage 8.4 mV, short circuit current 0.7 µA and maximum output power 1.5 nW. It corresponds to the output power density 10 µW/m2, and thus confirms the suitability of CuI/NC to obtain electricity by the harvesting the waste environmental heat.

In this study we present a new flexible thin-film thermoelectric (TE) material consisted of biocompatible and biodegradable polymer nanocellulose (NC) as substrate and thin films of copper iodide $(\gamma-CuI)$ as a basic TE p-type semiconductor. For a preparing 8 $\mu m$ thick nanocellulose film we used a widespread plant common reed (Phragmites australis) and a fabrication process 2,2,6,6-tetramethylpiperidine-l-oxyl (TEMPO)-mediated oxidation. The 1. $8-3.0\mu m$ thick nanostructured films CuI were deposited onto NC substrates via low-temperature aqueous cheap, facile, and scalable fabrication technique Successive Ionic Layer Adsorption and Reaction (SILAR). Thus we obtained TE material $NC/CuI$ with high thermoelectric power factor $S^{2}/\rho$ up to 60 $\mu W/(m\cdot K^{2})$. Lightweight flexible biodegradable thin-film TE modules based on thin-film samples NC/CuI were equipped with vacuum deposited thin Cr films providing ohmic contacts. Their output power densities up to 36 $\mu W/cm^{2}$ at difference of temperature between their ends 40 K, are comparable to those for state-of-the-art solid and flexible thermoelectric films.

In the paper the biopolymer substrates were made from nanocellulose (NC), which is extracted from organosolvent reed cellulose using 2,2,6,6-tetramethylpiperidin-1-oxyl reagent (TEMPO). Nickel-based thin films were deposited on the surface of nanocellulose by RF magnetron sputtering. The peculiarities of surface morphology and chemical composition of inorganic material on the surface of biopolymer substrate were studied. Flexible strain sensors were obtained from nickel busbars on the surface of nanocellulose. The influence of overall sizes of nickel busbars on piezoresistive parameters of flexible sensors was established. It was determined that the maximum strain sensitivity is observed for a nickel busbar with a width of 1 mm, a thickness of 250 nm, a length of 15 mm and was 195,8⋆ 10-3 %. The magnitude of drift in time was 0,17 %/min. Obtained strain sensors were tested on mechanical strength depending on nickel busbar sizes. It was shown that the presence of nickel thin film increases the strength of strain sensors by 40%: from 13.8 MPa for pure nanocellulose to 19.5-19.6 MPa for nanocellulose with nickel thin films.

Background. The development of technologies for obtaining materials from plant raw materials, the use of which improves the consumer properties of cardboard and paper products and does not pollute the environment with harmful substances from synthetic polymers, is an urgent problem of our time. Objective. The purpose of the paper is to obtain pulp and nanocellulose from reed stalks by environmentally friendly methods and apply nanocellulose to improve the quality parameters of paper for packaging food products on automatic machines. Methods. To obtain pulp from reed stalks with a minimum residual content of lignin and minerals, two processing stages were used: alkaline extraction and organosolv cooking at a temperature of 97 ± 2 °C. Nanocellulose was obtained by the oxidation of organosolv reed pulp with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in the TEMPO / NaBr / NaClO system, which is more environmentally friendly than acid hydrolysis. The resulting nanocellulose was applied to paper samples from waste paper and sulphate unbleached pulp at a consumption from 1 to 3 g/m2. Results. Organosolv pulp was obtained from reed stalks with a residual lignin content of 0.53 % and an ash content of 0.045 %, which was used to obtain nanocellulose. The resulting nanocellulose particles have a transverse size in the range of 5–20 nm, a length of up to several micrometers, and the tensile strength of nanocellulose films is up to 60 MPa. It is shown that the application of nanocellulose to the surface of the samples increases the breaking strength and breaking length, and reduces the surface absorbency of paper. It was determined that with a nanocellulose consumption of up to 3 g/m2, paper samples have indicators that meet the requirements of the standard for paper for packaging food products on automatic machines. Conclusions. The use of nanocellulose from reed stalks as a hardening substance for paper production will allow replacing environmentally harmful polymer additives and up to 50 % of more expensive softwood pulp with waste paper, while maintaining paper quality indicators at the level of standard requirements.

The study describes the preparation of pulp and nanocellulose from non-wood plant materials, as well as an improved properties of paper and cardboard for mass production. The pulps from wheat straw, kenaf and flax fibers were prepared by the environmentally friendly organosolv method—cooking in a solution of isobutanol or peracetic acid. The organosolv pulps used to prepare nanocellulose had traces of lignin and mineral substances. The process of hydrolysis of the investigated organosolv pulps was optimal when carried out under the following conditions: 43% sulfuric acid, temperature 60 °C, hydrolysis time 90 min and ultrasonic treatment 60 min. Using the methods of SEM, XRD, TEM, AFM and TGA, the structure and properties of organosolv pulps and nanocellulose were studied. The use of nanocellulose in bulk and on the surface of mass types of paper and cardboard—paper for corrugation, offset paper, recycled containerboard and cardboard for flat layers of corrugated cardboard were investigated. We established the positive effect of nanocellulose application on the physical and mechanical properties of paper and cardboard. Low consumption of nanocellulose allows production of the paper and cardboard with properties that meet the requirements to appropriate standards and replacement of synthetic reinforcing materials.

The chapter describes the chemical structure and hierarchical organization of cellulose fibers, characteristics of non-wood plant raw materials (NWPM), and methods for preparing pulp and nanocellulose (NC). NWPM have the necessary reserves and properties to make up for a possible shortage of wood fiber for pulp production. The methodology for evaluating the efficiency of the delignification processes of plant raw materials is presented. A two-stage technology for producing pulp for the preparation of NC by environmentally friendly organosolvent methods of NWPM delignification is proposed. Methods for preparing nanocellulose are described. The technological parameters of the extraction of NC from pulp are discussed. The influence of NC on the properties of composite materials is analyzed. Areas of use for NC from NWPM are shown.

We report gravimetric, electric, and spectral properties of the solid-state water-nanocellulose systems with different water content. The systems with the nanocellulose content of 0.15, 0.3, 0.6, 96.6, and 97.3% undergo dielectric relaxation at temperatures between −100 and 0 °C, whose nature differs from that of the dielectric relaxation in pure water. The relaxation process in water-nanocellulose systems was found to be due to the dipole thermal polarization. This process is determined by the behavior of the surface layers of the nanocrystals, surrounded by the hydrated shell; its mechanism is due to the conformational motion of the methylol groups on the surface of the nanocellulose crystals.

This work describes methods for the preparation of pulp from non-wood plant materials, nanocellulose, for capacitive and resistive humidity sensors. The properties of nanocellulose from organosolvent pulps from wheat straw, kenaf, miscanthus, and reed were described. The nanocellulose was obtained by two methods – by hydrolysis of sulfuric acid and by oxidation of TEMPO (2,2,6,6-tetramethylpiperidin-l-oxyl). The response of capacitive and resistive humidity sensors based on nanocellulose was in the range of 0, 61-21nF and in the range of 1,3$\ast10^{1}$ – $2,1\ast10^{4}$ correspondingly in depend on initial raw materials, method of nanocellulose obtaining as well as weight of it on sensitive surface. The maximum value of sensitivity for both types of sensors reached up to 0,14 (% RH)$^{-1}$.

The morphology, optical absorption and luminescence properties were used to determine spectral characteristics of optical transmittance and absorbance, coefficient of absorption, the values of the optical band gap and Urbach energy of thin nanocellulose films and nanocellulose filled with microcrystalline cellulose or graphene oxide. The influence of noted additives on the spectral properties of composites and the characteristics of the optical band gap has been discussed. It was suggested that the difference in the effect of these additives on the properties of composites could be caused by different mechanisms of interaction of additives with the surface of nanocellulose particles.

Molybdenum oxide thin films were synthesized by reactive ion beam sputtering technique. The effect of deposition temperature and annealing on surface morphology, electrical and optical parameters of molybdenum oxide thin films and heterojunctions based on them were determined. In particular, obtained thin films exhibit photosensitive properties (photo-sensitivity coefficient is about 200 μA/1mV), heterojunctions based on them are characterized by the rectifying properties (rectification coefficient is almost 300 at applied voltage of 0.5V) and photovoltaic properties (open-circuit voltage is 215 mV and short-circuit current with one point contact is up to 2.4 mA).

We present the study of the preparation of pulp and nanocellulose from Miscanthus × giganteus to improve the quality of the paper for bags. The organosolv miscanthus pulp (OMP) was prepared by the environmentally friendly organosolv method—cooking in a solution of peracetic acid at the first stage and the alkaline treatment at the second stage. Nanocellulose was obtained by hydrolysis of never-dried OMP and subsequent ultrasonic treatment. Structural changes and crystallinity index of OMP and nanocellulose were studied by SEM and FTIR methods. X-ray diffraction analysis confirmed an increase in the crystallinity of OMP and nanocellulose as a result of thermochemical treatment. The nanocellulose had a density of up to 1.6 g/cm3, transparency up to 82%, a crystallinity index of 76.5%, and tensile strength up to 195 MPa. The AFM showed that the particles of nanocellulose have a diameter in the range from 10 to 20 nm. A TGA analysis confirmed that nanocellulose films have a denser structure and lower mass loss in the temperature range 320–440 °C compared to OMP. We established the positive effect of nanocellulose application on the physical and mechanical properties of paper for bags. The application of nanocellulose allows replacing synthetic reinforcing materials and more expensive sulfate unbleached pulp with waste paper in the production of paper and cardboard.

The possibility of obtaining nanocellulose from organosolv pulp from kenaf fibers by hydrolysis with sulfuric acid of a lower concentration (43%) compared with the traditional conditions (60%-65%) is demonstrated. The structure and properties of the nanocellulose were studied by SEM, FT-IR, XRD, TEM, AFM, and TGA. It was found that the product has a degree of crystallinity of up to 80%, and forms a porous network of particles with diameters of 10-28 nm. The nanocellulose films have a density of 1.39 g/cm3, transparency of up to 76%, and tensile strength of 40 MPa.

Background. Obtaining from annually renewable plant raw materials, in particular from hemp fiber, microcrystalline cellulose (MCC), which is suitable for use in the chemical industry. Objective. The was aim of the paper is to develop a technology for obtaining MCC from hemp fibers to reduce the number of the technological process stages and to determine the optimum values of the main technological parameters of the chelating and hydrolysis processes of peracetic hemp pulp, in which the quality indicators of the obtained MCC will meet the requirements of regulatory documents. Methods. Peracetic cooking of hemp fibers was carried out at liquor to solid ratio 10: 1 and temperature of 90 ± 1 °C, ranging from 60 to 240 min. The process of chelating pulp by Trilon B was investigated at consumption from 5 to 30 % in acidic and alkaline environments. At the final stage of MCC preparation, the hemp pulp hydrolysis process was carried out by sulfate acid at its concentration of 0.5 to 2.0 %, liquor to solid ratio 15:1 and a temperature of 90 ± 1 °C for 90 min. The quality indices of the obtained microcrystalline cellulose were determined by standard methods. Results. The high efficiency of the peracetic method of pulp production from hemp fiber is shown. It has been experimentally proved that the chelating process of hemp pulp is expediently carried out in acid environment at a Trilon B consumption of 20 % from the the bone dry process weight. It is shown that the MCC can be obtained by the hydrolysis of peracetic hemp pulp with a solution of 1.5 % sulfuric acid at a temperature of 90 °С during 90 min that satisfies the requirements of regulatory documents. Conclusions. The proposed technology for the MCC production from hemp fibers reduces the cost of finished products by eliminating the bleaching stage of pulp as well as due to the use of domestic renewable plant raw materials, in particular hemp fibers compared with imported cotton or softwood pulp. The obtained MCC meets the requirements of technical conditions and can be used in the chemical industry as a sorbent or filler in the production of plastics and a water stabilizer for paints and emulsions.

The data on the preparation of nanocellulose from organosolvent miscanthus pulp and its application as coating layer in the production of bag paper are reported. The influence of technological factors on the properties of nanocellulose films was determined. The obtained nanocellulose films had density up to 1.46 g/cm3, transparency up to 80%, crystallinity degree up to 77% and tensile strength up to 70 MPa. The properties of nanocellulose films studied by means of electron absorption spectra, XRD and AFM methods. The bag paper with consumption of nanocellulose of 5 g/m2 has mechanical properties of 12–68% higher and the elongation increases 2.9 times than paper without the use of surface treatment. The using of obtained nanocellulose as a coating layer exhibit great potential its application for improving fiber-based mechanical and barrier properties of paper and cardboard.

The procedure of holocellulose content determination in non-wood plant raw materials was developed. The strength properties of pulp obtained from sunflower stalks by neutral-sulphite, soda, alkaline sulphite-anthraquinone-ethanol and peracetic methods of delignification were studied. Methodology of comparison of plant materials delignification methods using new lignin-carbohydrate diagram was proposed. It was shown, that the alkaline sulphite-anthraquinone-ethanol method of pulping is characterized by the highest delignification degree and is the most efficient among the studied methods

Miscanthus x giganteusstalks were used to make organosolvent pulp and nanocellulose. The organosolvent miscanthus pulp (OMP) was obtained through thermal treatment in the mixture of glacial acetic acid and hydrogen peroxide at the first stage and the alkaline treatment at the second stage. Hydrolysis of the never-dried OМP was carried out by a solution of sulfuric acid with concentrations of 43% and 50% and followed by ultrasound treatment. Structural changes and the crystallinity index of OMP and nanocellulose were studied by SEM and FTIR methods. X-ray diffraction analysis confirmed an increase in the crystallinity of OMP and nanocellulose as a result of thermochemical treatment. We show that nanocellulose has a density of up to 1.6 g/cm3, transparency up to 82%, and a crystallinity index of 76.5%. The AFM method showed that the particles of nanocellulose have a diameter in the range from 10 to 20 nm. A thermogravimetric analysis confirmed that nanocellulose films have a denser structure and lower mass loss in the temperature range of 320–440°C compared to OMP. The obtained nanocellulose films have high tensile strength up to 195 MPa. The nanocellulose obtained from OMP exhibits the improved properties for the preparation of new nanocomposite materials.

The data on nanocellulose preparation from organosolv kenaf pulp and its application in the production of corrugating paper are reported. The influence of technological factors on the properties of nanocellulose films was determined The obtained nanocellulose films had to 1.4 g/cm3density, 78 % transparency, 80 % crystallinity degree and 77 MPa tensile strength. Other properties of nanocellulose were studied by means of XRD, AFM and TGA methods. The corrugating paper with a coating consumption of 5 g/m2nanocellulose has mechanical properties 18-34% higher than paper without the use of surface treatment. The use of obtained nanocellulose as coating layer has great potential to improve fiber-based mechanical and barrier properties of corrugating paper.

The possibility of obtaining the nanocellulose from organosolv straw pulp (OSP) was studied. OSP obtained by cooking in a system of isobutyl alcohol–H2O–KOH–hydrazine. It is found that the subsequent processing of OSP with acetic acid and hydrogen peroxide and hydrolysis of sulfate acid and ultrasound treatment allow obtaining the nanofibrillated cellulose (NFC). The structural change and crystallinity degree of OSP and NFC were studied by the SЕМ and XRD techniques. It has been established that NFS has a density up to 1.3 g/cm3, transparency up to 60%, and crystallinity 72.2%. The TEM method showed that NFC forms the mesh with diameter of particles in the range from 20 to 40 nm. The method of thermogravimetric analysis was confirmed that NFC films have more dense structure and smaller mass loss in temperature ranging 220–260 ° C compared with OSP.

Проблематика. Розробка технології одержання пероцтової целюлози із соломи вівса та використання її у виробництві одного із масових видів паперу.Мета дослідження. Визначення оптимальних значень технологічних параметрів пероцтового варіння на показники якості пероцтової целюлози із соломи вівса.Методика реалізації. Варіння січки соломи вівса проводили пероцтовою кислотою за температури 95 ± 1 °С упродовж 90, 120, 150 і 180 хв за гідромодуля 8:1 і 7:1, а також із використанням каталізатора – вольфрамату натрію. Для визначення фізико-механічних показників пероцтової целюлози із соломи вівса виготовляли лабораторні зразки паперу масою 70 г/м2.Результати дослідження. Встановлено оптимальні значення технологічних параметрів (температури, тривалості, гідромодуля, концентрації пероксиду водню і пероцтової кислоти) процесу делігніфікації соломи вівса. Показано, що додавання до варильного розчину каталізатора вольфрамату натрію з витратою до 1 % від маси рослинної сировини сприяє зменшенню вмісту лігніну в целюлозі до 15 %. Побудовано діаграму залежності виходу целюлози від вмісту в ній залишкового лігніну для різних способів делігніфікації представників недеревної рослинної сировини. Підтверджено високу ефективність пероцтового методу одержання целюлози із недеревної рослинної сировини, зокрема із соломи вівса. Визначено, що одержана пероцтова целюлоза із соломи вівса має високі значення фізико-механічних показників. Висновки. Пероцтова целюлоза із соломи вівса може використовуватися для виробництва масових видів паперу і картону, зокрема обгорткового паперу марки Г., Background. Development of technology for obtaining peracetic pulp from oat straw and its use in the production of one of the paper mass types.Objective. Determination of peracetic cooking technological parameters’ optimal values for oat straw peracetic cellulose quality indicators.Methods. The oat straw cooking was carried out with peracetic acid at 95 ± 1 °C from 90 to 180 min for hydromodulus 8:1 and 7:1, using a sodium tungstate catalyst. To determine the oat straw peracetic cellulose mechanical indexes, laboratory samples of paper weighing 70 g/m2 were made.Results. Technological parameters’ optimum values (temperature, cooking duration, hydromodulus, hydrogen peroxide and acetic acid concentration) for the oat straw delignification process were established. It is shown that the sodium tungstate catalyst addition to the cooking solution at a rate of up to 1 % of the plant raw material weight helps to reduce the lignin content in cellulose to 15 %. A diagram of the cellulose yield dependence on its residual lignin content for various methods of non-wood plant material species delignification is constructed. The high efficiency of the peracetic method for obtaining cellulose from non-wood plant raw materials, in particular from oat straw, has been confirmed. It is determined that the obtained peracetic cellulose from oat straw has high mechanical indexes.Conclusions. Oat straw peracetic cellulose can be used for the production of paper and cardboard mass types, in particular wrapping paper., Проблематика. Разработка технологии получения перуксусной целлюлозы из соломы овса и использование ее в производстве одного из массовых видов бумаги.Цель исследования. Определение оптимальных значений технологических параметров перуксусной варки на показатели качества перуксусной целлюлозы из соломы овса.Методика реализации. Варку сечки соломы овса проводили перуксусной кислотой при температуре 95 ± 1 °С в течение 90, 120, 150 и 180 мин при гидромодуле 8:1 и 7:1, а также с использованием катализатора – вольфрамата натрия. Для определения физико-механических показателей перуксусной целлюлозы из соломы овса изготавливали лабораторные образцы бумаги массой 70 г/м2.Результаты исследования. Установлены оптимальные значения технологических параметров (температуры, продолжительности, гидромодуля, концентрации пероксида водорода и перуксусной кислоты) процесса делигнификации соломы овса. Показано, что добавление к варочному раствору катализатора вольфрамата натрия с расходом до 1 % от массы растительного сырья способствует уменьшению содержания лигнина в целлюлозе до 15 %. Построена диаграмма зависимости выхода целлюлозы от содержания в ней остаточного лигнина для различных способов делигнификации представителей недревесного растительного сырья. Подтверждена высокая эффективность перуксусного метода получения целлюлозы из недревесного растительного сырья, в частности из соломы овса. Определено, что полученная перуксусная целлюлоза из соломы овса имеет высокие значения физико-механических показателей.Выводы. Перуксусная целлюлоза из соломы овса может использоваться для производства массовых видов бумаги и картона, в том числе оберточной бумаги марки Г.

The influence of basic technological parameters of the organosolvent delignification of corn stalks process on the pulps quality has been investigated. The adequate regression equations of the process of obtaining pulps using the method of full factorial experiment have been obtained. The optimal values of technological parameters of organosolvent delignification of corn stalks have been calculated. The possibility of bleaching the organosolvent pulp obtained from corn stalks by hydrogen peroxide without the use of chlorine compounds to whitenees more than 80 % has been proved by the experiments.

A new, environmentally cleaner, technology of obtaining microcrystalline cellulose of fibers of hemp was proposed. The various stages of obtaining microcrystalline cellulose were studied and the optimum values of technological parameters of alkali extraction of hemp fibers, organosolv pulping, chelation and hydrolysis of cellulose were defined. It was determined that the consistent treatment of fibers of hemp by extraction of 5 % KOH solution during 210 minutes at the temperature of 95 °С, performic cooking in a mixture of 85 % formic acid and 30 % of hydrogen peroxide in the ratio of 60:40 of volume % at 100 °C during 210 min, chelation by the solution of trilon B of the concentration of 10 g/l during 30 min at 50 °C and hydrolysis by a mixture of 98 % acetic acid and 30 % of hydrogen peroxide solution in the ratio of 70:30 of volume %, allows obtaining microcrystalline cellulose in the form of white powder with a degree of polymerization 80 and the content of sulfate ash of 0.10 %. Using the methods of scanning electronic microscopy, thermogravimentric analysis and X­ray diffraction confirmed that the consistent multistage chemical treatment increases the content of crystalline part of cellulose by the removal of extractive and mineral substances, hemicelllulose and amorphous fraction of cellulose of the fibers of hemp. Application of the proposed technology of obtaining microcrystalline cellulose from the fibers of hemp is environmentally more friendly and enables to reduce significantly the cost of finished products by using national, annually renewable plant raw materials compared to imported cotton or pine cellulose.

The problem of considering separately the contributions of the universal and specific solvation of components of a system to the thermodynamic characteristics of a heteromolecular association process are discussed. An expression is presented for calculating the equilibrium constants of the process of formation of addition products under universal solvation conditions, where the change in all of the thermodynamic characteristics of the process is determined by only a change in the dielectric constant of the medium.

The development of the nanomaterials with the advanced functional characteristics is a challenging task because of the growing demand in the market of the optoelectronic devices, biodegradable plastics, and materials for energy saving and energy storage. Nanocellulose is comprised of the nanosized cellulose particles, properties of which depend on characteristics of plant raw materials as well as methods of nanocellulose preparation. In this study, the effect of the mechanochemical treatment of bleached softwood sulfate pulp on the optical and mechanical properties of nanocellulose films was assessed. It was established that the method of the subsequent grinding, acid hydrolysis and ultrasound treatment of cellulose generated films with the significant transparency in the visible spectral range (up to 78 % at 600 nm), high Young's modulus (up to 8.8 GPa), and tensile strength (up to 88 MPa) with increased ordering of the packing of the cellulose macromolecules. Morphological characterization was done using the dynamic light scattering (DLS) analyzer and transmission electron microscopy (TEM). The nanocellulose particles had an average diameter of 15-30 nm and a high aspect ratio in the range 120-150. The crystallinity was increased with successive treatments as shown by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The thermal degradation behavior of cellulose samples was explored by thermal gravimetric analysis (TGA).