POWDERED CELLULOSIC MATERIALS: OVERVIEW, CLASSIFICATION, CHARACTERISTICS AND FIELDS OF APPLICATION

Recently, due to the growing interest in powdered cellulosic materials, a large number of studies have been carried out on various methods of their preparation. The main interest is associated with new opportunities for research on nanocellulose. However, for a complete understanding, it is necessary to have information about all powdered cellulosic materials and the peculiarities of their preparation. This paper provides an overview of powdered cellulosic materials, presents their characteristics, and describes the properties of the materials. It is shown that the morphology of its fiber, as well as the ratio of crystalline and amorphous regions of cellulose, has a significant effect on the properties of the material. Peculiarities of obtaining powdered cellulose materials are discussed, depending on the required properties, and existing research in the field of mechanical, chemical and enzymatic processing of cellulose is presented. The main areas of application of various powdered cellulose materials are described, as well as the current situation on the market, examples of both domestic and foreign manufacturers are given. The information on powdered cellulose materials is generalized, their classification is given, which is consistent with the modern concepts described in the scientific works of researchers from all over the world.

Investigation of the possibility of obtaining powdered cellulose using a non-knife method of grinding fibrous semi-finished products

The pulp and paper industry occupies one of the leading places among various sectors of the national economy in terms of versatility and prevalence throughout the world, as well as the need for its products for the economy of any country. In addition, with the advent of printing systems that operate at an increasingly faster speed and perform complex tasks, the requirements for the properties and quality of paper have increased. At present, powdered cellulose is a promising direction in the development of the pulp and paper industry. The article discusses the possibility of obtaining powdered cellulose with preliminary grinding on a knifeless grinding plant of the “jet-barrier” type. The morphological properties of the fiber and the degree of polymerization of powdered cellulose are given depending on the degree of grinding.

Investigation of the influence of the pattern of a disc mill set on the process of obtaining powdered pulp

On the market of pulp and paper products, new requests for more narrowly targeted products appear every year. To stay competitive in the market, manufacturers need to use not only traditional types of fibrous materials, but also use with excellent characteristics from the usual cellulose. The article discusses the role of the knife process of pulp grinding. A method for producing powdered cellulose with preliminary grinding in a disk mill is proposed. The paper-forming properties of the pulp and the degree of polymerization of powdered cellulose, depending on the degree of grinding, are given.

Segmented bio-based polyurethane composites containing powdered cellulose obtained from novel bio-based diisocyanate mixtures

A considerable number of research works focus on the positive influence of cellulose on the properties of polymer-based composites and their wide range of application possibilities. The present work is focused on the synthesis of novel bio-based polyurethane (bio-PU) composites filled with powdered cellulose (microcellulose, MC) in an amount of 5 wt.%. Bio-PU composites were synthesized via a non-solvent prepolymer method. First, the prepolymer was synthesized from diisocyanate mixture based on hexamethylene diisocyanate and bio-based polyisocyanate Tolonate™ X Flo 100 and α,ω-oligo(ethylene-butylene adipate)diol which contained cellulose. Then, resulted prepolymer was extended by bio-based 1,4 butanediol (bio-BDO). Bio-PU composites were obtained with the different [NCO]/[OH] molar ratios: 0.95, 1.0, 105 and 1.1. Special attention was paid to the influence of MC on the phase separation between soft and hard segments of bio-PU by studying the chemical structure, morphology and thermal and mechanical properties of the prepared cellulose-based composites.

"PALLADIUM ON COAL" CATALYST OBTAINED BY PYROLYSIS OF POWDER CELLULOSE GRANULES IM-PREGNATED WITH PALLADIUM NITRATE

By pyrolysis of powdered cellulose granules impregnated with palladium nitrate, catalysts of 1–8% Pd / C were obtained. Pyrolysis was carried out in a reactor with a water seal at 600 ° C. Metal reduction was carried out with pyrolysis gases and matrix carbon. It was found that the ash content of powdered cellulose granules is ~ 40 times less than the ash content of sulfate cellulose, from which they were made. It was shown by X-ray phase analysis and electron microscopy that palladium in the catalysts is present in the form of Pd (0) nanoparticles uniformly covering carbon fibers and shapeless massive metal precipitates up to 20 μm in diameter. In catalysts 1–3% Pd / С, nanoparticles 10–40 nm dominate (> 95%), in 8% Pd / С, 20–70 nm. The share of massive metal formations in Pd (1%) / C, Pd (3%) / C and Pd (8%) / C is: ~ 2%, ~ 5% and ~ 60%, respectively. They consist of aggregated spherical particles 0.05–0.15 µm in diameter. XRD palladium oxide was not detected in the catalysts. The presence of palladium nitrate in powdered cellulose during its carbonization has a significant effect on the formation of the carbon matrix. With an increase in the content of palladium nitrate in powdered cellulose, the yield of carbon material decreases and its total porosity increases. Infrared spectroscopy revealed the presence of oxygen-containing ether groups in the carbon matrix of palladium catalysts. The activity of catalysts in the model process of decomposition of hydrogen peroxide increases with increasing dispersion of palladium nanoparticles.

Fermentation Characteristics and In Vitro Digestibility of Fibers and Fiber-Rich Byproducts Used for the Feeding of Pigs

Dietary fibers may have positive impact on health and wellbeing of pigs. The study examined physicochemical properties of two lignocelluloses (including and excluding bark), powdered cellulose, Aspergillus niger mycelium, lucerne chaff, soybean shells, wheat bran, and sugar beet pulp in relation to fermentability and digestibility using in vitro batch-culture incubation. Maize starch and a purified cellulose were used as standardized substrates for classification of the test substrates. The substrates covered a wide range regarding their physicochemical properties. Swelling capacity (SC) was 9–411%, water binding capacity (WBC) was 4.4–14.3 g/g dry matter (DM), and water holding capacity (WHC) was 4.1–10.6 g/g DM. Gas production and other fermentation parameters—namely post-incubation pH, CH4, NH3, and short chain fatty acids (SCFA) concentrations—revealed a significant fermentation of sugar beet pulp, soybean shells, lucerne chaff, wheat bran, A. niger mycelium, and powdered cellulose, whereas the lignocelluloses were not fermented. Significant correlations were found between the physicochemical properties and the fermentation parameters (p < 0.05). Enzymatic pre-digestion mostly reduced gas, NH3, and SCFA production. In vitro digestibility of DM (IVDMD) and organic matter (IVOMD) was mostly negligible after enzymatic pre-digestion. Fermentation alone led to only 0.10–0.15 IVDMD and 0.14–0.15 IVOMD in lignocelluloses and powdered cellulose, respectively, but 0.44–0.37 IVDMD and 0.46–0.38 IVOMD in the remainder of substrates (p < 0.05). In vitro digestibility was again correlated with the physicochemical properties of the substrates and the fermentation parameters (p < 0.05). The fiber preparations and fiber-rich byproducts were fermented to a relevant extent. In contrast, lignocelluloses were not fermented and can be used rather as bulk material.

HYDROPHILIC RUBBER BASED ON BUTADIENE-NITRILE RUBBER AND POWDER CELLULOSE OF PLANT ORIGIN

It has been established that the introduction of powdered cellulose, obtained by chemo-mechanical destruction from oat straw, into the composition of rubbers as a hydrosorption filler increases the conditional tensile strength of vulcanizates in comparison with samples without this filler. It was revealed that the degree of swelling of rubbers containing powdered cellulose from oat straw, the pH of the aqueous medium and the degree of mineralization have little effect.

THE INFLUENCE OF THE KNIFE METHOD OF GRINDING PULP ON THE PROCESS OF OBTAINING POWDERED CELLULOSE

This article presents the classification of the resulting types of powdered cellulosic materials, their scope, as well as the problems arising during production. The main properties of powder cellulose materials are considered. Analyzed the quality indicators of the pulp, previously ground in a disc mill. The main technological parameters of the experimental setup and the comparative characteristics of the used knife grinding sets are presented. In the course of the experimental research, knife grinding sets with straight and curved knives were used. The data obtained confirmed the previously put forward hypothesis about the predominant fibrillation of cellulose fiber milled using a grinding set with a curved blade shape. This feature of the headset design is especially important when grinding hardwood pulp, which has a lower initial value, compared to softwood pulp. The data obtained in determining the degree of grinding, water retention capacity, fiber length of softwood and hardwood cellulose after knife grinding and the degree of polymerization after hydrolysis are presented. A method for producing powdered cellulose material with characteristics similar to microcrystalline cellulose is considered. The regulated parameters of the hydrolysis process are set and a comparison is made of the degree of polymerization of the considered samples of powdered cellulose.

INFLUENCE OF THE FIBROUS MASS GRINDING METHOD ON THE PROCESS OF POWDER CELLULOSE PRODUCTION

The article presents results of experimental studies of cellulose properties depending on different shaped knife tooling of the disk mill used for grinding. A method for production of powdered cellulose material with characteristics close to microcrystalline cellulose is considered.