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.
This study investigates powdered cellulose materials, particularly nanocellulose derived from plant and bacterial sources. The nanocellulose was generated by hydrolyzing bleached sulphate softwood and hardwood pulp samples with strong acids. The original materials are present in the product lines of leading Russian pulp and paper companies. The bacterial cellulose was produced under laboratory conditions from Medusomyces gisevii. The dimensional parameters of the nanocellulose samples were evaluated using electron microscopy, and the degree of polymerization was measured by determining the viscosity of the cellulose solutions in cadoxene. The bleached softwood pulp had a nanocellulose particle length of 80–200 nm, a particle diameter of 80–100 nm, and a degree of polymerization of 60. The bleached hardwood pulp had a particle length of 80–150 nm, a particle diameter of 70–100 nm, and a degree of polymerization of 50. The bacterial nanocellulose had a particle length of 120–250 nm, a particle diameter of 70–120 nm, and a degree of polymerization of 110. Suspensions of various concentrations (from 1 to 10 %) were prepared from nanocellulose samples, which were subsequently used as reinforcing additives in cardboard samples. The additive was applied to the surface in one or two layers. Additives of nanocellulose preparations reduced the breaking length (from 9.6 to 40.4 %) along with an increase in cardboard density (from 6.3 to 23.8 %), tensile rigidity (from 14.0 to 25.0 %) and bursting strength (up to 31.9 %). The best results were obtained by applying a nanocellulose suspension of bleached softwood pulp to the board surface in two layers: a 9.6 % decrease in breaking length was observed with an increase in density of 23.8 %, tensile rigidity of 25.0 %, and bursting resistance of 31.9 % relative to the control sample. Therefore, the study showed the possibility of using nanocellulose suspensions derived from plants and bacterial sources by acid hydrolysis for the surface treatment of cardboard. For citation: Toptunov Е.А., Sevastyanova Yu.V., Vashukova K.S. Surface Treatment of Cardboard with Plant and Bacterial Derived Nanocellulose Suspensions. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 162–172. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-162-172
The global development of the bioeconomy is impossible without technologies for comprehensive processing of plant renewable resources. The use of proven pretreatment technologies raises the possibility of the industrial implementation of the enzymatic conversion of polysaccharides from lignocellulose considering the process’s complexity. For instance, a well-tuned kraft pulping produces a substrate easily degraded by cellulases and hemicelulases. Enzymatic hydrolysis of bleached hardwood kraft pulp was carried out using an enzyme complex of endoglucanases, cellobiohydrolases, β-glucosidases, and xylanases produced by recombinant strains of Penicillium verruculosum at a 10 FPU/g mixture rate and a 10% substrate concentration. As a result of biocatalysis, the following products were obtained: sugar solution, mainly glucose, xylobiose, xylose, as well as other minor reducing sugars; a modified complex based on cellulose and xylan. The composition of the biomodified kraft pulp was determined by HPLC. The method for determining the crystallinity on an X-ray diffractometer was used to characterize the properties. The article shows the possibility of producing biomodified cellulose cryogels by amorphization with concentrated 85% H3PO4 followed by precipitation with water and supercritical drying. The analysis of the enzymatic hydrolysate composition revealed the predominance of glucose (55–67%) among the reducing sugars with a maximum content in the solution up to 6% after 72 h. The properties and structure of the modified kraft pulp were shown to change during biocatalysis; in particular, the crystallinity increased by 5% after 3 h of enzymatic hydrolysis. We obtained cryogels based on the initial and biomodified kraft pulp with conversion rates of 35, 50, and 70%. The properties of these cryogels are not inferior to those of cryogels based on industrial microcrystalline cellulose, as confirmed by the specific surface area, degree of swelling, porosity, and SEM images. Thus, kraft pulp enzymatic hydrolysis offers prospects not only for producing sugar-rich hydrolysates for microbiological synthesis, but also cellulose powders and cryogels with specified properties.
Основным полуфабрикатом для производства бумаги для гофрирования (флютинга), используемой в композиции тарного картона, является полуцеллюлоза из лиственных пород древесины. Производство полуцеллюлозы базируется напредварительной химической и последующей механической переработке древесной щепы или однолетних растений. Технология производства полуцеллюлозы с использованием в качестве варочного реагента - зеленого щелока позволяет упростить процесс приготовления варочного раствора и сократить схему регенерации химикатов из отработанных щелоков. Однако сведения о технологических параметрах варки, качестве полуцеллюлозы представлены недостаточно полно, отсутствуют подробные данные об избирательности процесса делигнификации лиственных пород древесины, произрастающих в СЗФО, а также недостаточно информации о составе и свойствах отработанного щелока, влиянии породного сырья на свойства щелоков. Исследование выполнено с целью изучения свойств отработанного (оранжевого) щелока, а именно его плотности, полученного при варке лиственной полуцеллюлозы с различным соотношением зеленого и белого щелоков. Основываясь на результатах исследований свойств отработанного производственного щелока от варки лиственной полуцеллюлозы на смеси белого и зеленого щелоков: 1) не выявлено значительного влияния изменения соотношения зеленого и белого щелоков при варке лиственной полуцеллюлозы на плотность отработанного щелока в диапазоне температуры от 15 до 90 °С и концентрации сухих веществ от 5 до 10%; 2) разработана математическая модель - полином 1 степени, - достоверно характеризующая зависимость плотности отработанного щелока от концентрации и температуры для производства лиственной полуцеллюлозы с различным соотношением зеленого и белого щелоков: ρ = 0,992 + 0,0083 · х - 0,0003 · t - 0,000012 · х · t - 0,00000032 · t 2 - 0,0001158 · х 2. The main semi-finished product for the production of fluting is semi-cellulose from hardwood. Semi-cellulose production is based on preliminary chemical and subsequent mechanical processing of wood chips or annual plants. The technology for the production of semi-cellulose using green liquor makes it possible to simplify the process of preparing the cooking solution and the recovery of chemicals from waste liquors. This method is used abroad, in our country the method of cooking semi-cellulose with green liquor is currently carried out at one of the enterprises in Russia. However, at the moment, information on the technological parameters of cooking and the quality of semi-cellulose is not fully presented, there are no data on the selectivityof the delignification process (removal of lignin) of deciduous wood when cooking with green liquor, as well as information on the composition and properties of the spent liquor. The study was carried out with the aim of studying the properties of waste (orange) liquor, namely its density obtained by cooking hardwood semi-cellulose with different ratios of green and white liquors. Based on the results of studies of the properties of waste industrial liquor from hardwood semi-cellulose cooking on a mixture of white and green liquors: no significant effect of the ratio of green and white liquors during hardwood semi-cellulose cooking on the density of waste liquor in the temperature range from 15 to 90 °С and the concentration of dry substances from 5 to 10%; a mathematical model has been developed - a polynomial of the 1st degree, - reliably characterizing the dependence of the density of the spent liquor on concentration and temperature for the production of hardwood semi-cellulose with different ratios of green and white liquors ρ = 0,992 + 0,0083 · х - 0,0003 · t -- 0,000012 · х · t - 0,00000032 · t 2 - 0,0001158 · х 2.
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