This study analyzes the effect of artificial aging on the mechanical deformational and optical properties of various paper samples, which allows us to evaluate their durability and suitability for long-term storage. The methods of accelerated aging, measuring the breaking length, specific resistance, elongation, and fracture strength, were used, and the optical characteristics were estimated by the R₄₅₇ and CIE whiteness indices, as well as opacity. Mechanical measurements (breaking length, specific resistance, elongation, and fracture strength) revealed that bleaching reduces residual lignin and strengthens interfiber bonds, boosting pine pulp strength by up to 8%. Optical properties initially improve slightly, then increase sharply after the second bleaching cycle and stabilize, while opacity decreases, providing greater light transmittance. After accelerated aging, the following deterioration is observed: for bleached samples, R₄₅₇ whiteness changes; and for unbleached samples, CIE whiteness and opacity increase. After aging, aspen pulps and kraft papers retained over 90% of their initial strength and whiteness, whereas untreated and office papers lost up to 20–25%. These findings identify that aspen-based and kraft papers demonstrate better mechanical deformational and optical properties, which makes it possible to predict the operational characteristics of paper depending on the processing and aging methods used.

The article examines the prospects for using pyrolysis oil obtained from polyethylene waste as a component of liquid fuel. The relevance of the study is determined by the growing volume of plastic waste, the low level of its recycling, and the need to develop technologies capable of simultaneously reducing environmental impact and returning carbon-containing raw materials to secondary economic circulation. Based on an analysis of literature data, the features of polyethylene waste pyrolysis, the influence of technological parameters on the yield of the liquid fraction, and the physicochemical properties of the resulting pyrolysis oil were studied. It is shown that the process temperature, heating rate, and composition of the feedstock have a significant effect both on the yield of the liquid product and on its quality characteristics. It was found that pyrolysis oil has a high calorific value and a number of properties close to those of conventional liquid fuels, including diesel fuel and gasoline fractions. At the same time, it was revealed that its direct use is limited by a wide fractional composition, instability of certain performance indicators, and the need for additional treatment before practical application. It is noted that the most promising direction is the use of pyrolysis oil after preliminary treatment, primarily after distillation, as well as as a component of blended fuels. It is concluded that the pyrolysis of polyethylene waste is a promising direction of chemical recycling, combining the solution of environmental problems associated with reducing plastic waste volumes with the possibility of obtaining valuable liquid hydrocarbon products for further fuel and chemical use.

Growing concern over the environmental burden of petrochemical food packaging has directed attention toward agricultural and aquatic residues as secondary raw materials. This review examines polypropylene (PP) composites containing lignocellulosic fillers and biogenic calcium carbonate derived from eggshells and mollusc shells, together with chitosan- and nanocellulose-based coatings. Bulk modification, waterborne coatings and primers, barrier performance, active packaging, and migration safety are analysed in turn. As an organising framework, we propose a functional-separation strategy in which the bulk matrix carries mechanical load, a continuous coating governs mass transfer, and an active layer preserves the packaged food. Fillers are compared in terms of modulus gain and the retention of strength and impact resistance, with explicit acknowledgement of the limits inherent in comparing heterogeneous datasets. Replacing part of the PP with waste-derived material does not, in itself, confer biodegradability, a lower carbon footprint, or suitability for food contact. The principal knowledge gap is the scarcity of studies in which mechanical, barrier, and migration properties are measured on one and the same packaging system. Moderate filler loadings combined with a thin functional coating are identified as a direction warranting further verification, including assessment of recyclability and life-cycle performance.

Natural bentonite, dominated by montmorillonite-type layered aluminosilicates, is increasingly considered as an inexpensive and environmentally acceptable support or catalyst for the thermochemical conversion of waste carbon streams. Its relevance to catalysis arises from a combination of cation-exchange capacity, swelling behavior, hierarchical porosity after modification, and the possibility of generating Brønsted, Lewis, redox and metallic active sites. This review critically evaluates bentonite modification strategies—acid activation, alkaline and sodium exchange, inorganic oxide pillaring, transition- and noble-metal impregnation, organosilane or surfactant functionalization, and carbon-based hybridization—with emphasis on their consequences for texture, acidity, thermal stability, metal dispersion and catalytic behavior. The review then connects these structure–property relationships with the emerging application of modified bentonites in plastic-waste thermocatalysis and hydrogen-rich product formation. The recent literature indicates that acid-modified bentonite can substantially improve liquid hydrocarbon formation from polyethylene, binder-free bentonite pellets can operate at kilogram-batch scale for drop-in fuels, and Ni-, Fe- or Ni–Fe-modified bentonite-type catalysts can promote tar cracking, reforming and gas upgrading. However, direct evidence for high hydrogen yields from plastic waste over bentonite remains narrower than the evidence for liquid-fuel production, biomass pyrolysis or model-compound reforming. Therefore, this article distinguishes between direct plastic-waste evidence and transferable evidence from biomass, acetic acid, tar and hydrocarbon reforming studies. The analysis identifies Ni-impregnated acid-activated or pillared bentonite, Ni–Fe/bentonite, and La/Ca-promoted Ni/bentonite as the most promising routes for plastic-derived hydrogen-rich syngas, while acid activation alone is best regarded as a pretreatment rather than a complete catalyst design. Key limitations include catalyst deactivation by coke, metal sintering, chloride poisoning from PVC, inconsistent reporting of gas yields, and insufficient life-cycle and techno-economic analysis. A roadmap is proposed for designing reproducible, scalable bentonite catalysts for circular plastic-waste valorization.

В условиях роста объёмов пластиковых отходов и увеличения спроса на экологически чистые источники энергии разработка эффективных катализаторов для получения водорода приобретает особую актуальность. Целью настоящего исследования является синтез, физико-химическая характеристика и оценка каталитической активности таганского бентонита, модифицированного полидиметилакриламидом (ПДМА), в процессе каталитической конверсии углеводородов с получением водородсодержащего газа. В качестве носителя использован природный бентонит месторождения «Таган», предварительно подвергнутый кислотной активации и модифицированный 1 мас.% ПДМА методом пропитки. Структурные и морфологические особенности полученного катализатора исследованы методами рентгенофазового анализа (XRD), инфракрасной спектроскопии с преобразованием Фурье (FTIR), сканирующей и просвечивающей электронной микроскопии (СЭМ и ПЭМ). Каталитические испытания проводили в реакторе с фиксированным слоем при температуре 650 °С с последующим анализом газообразных продуктов методом газовой хроматографии. Результаты исследований показали, что модификация полидиметилакриламидом не приводит к разрушению кристаллической структуры монтмориллонита, а способствует формированию полимер-минерального нанокомпозита с развитой пластинчатой морфологией и улучшенными поверхностными характеристиками. В составе газообразных продуктов каталитической конверсии установлено содержание водорода 35,9 об.%, метана 34,1 об.% и углеводородов фракции C₂–C₃ 29,5 об.%. Выход водорода составил 1,28 ммоль/г, а отношение H₂/CH₄ достигло 1,05, что свидетельствует об эффективном протекании реакций крекинга и дегидрирования на поверхности катализатора. Полученные результаты подтверждают перспективность использования ПДМА-модифицированного таганского бентонита в качестве доступного и эффективного гетерогенного катализатора для термокаталитической переработки полимерных отходов с получением водородсодержащего газа и могут служить основой для разработки экологически безопасных технологий утилизации пластиковых отходов и производства альтернативных энергоносителей.