This study focuses on the development of environmentally sustainable polypropylene (PP)-based composites with the potential for biodegradability by incorporating cellulose and the oligomeric siloxane ES-40. Targeting industrial applications such as fused deposition modeling (FDM) 3D printing, ES-40 was employed as a precursor for the in situ formation of silica particles via hydrolytic polycondensation (HPC). Two HPC approaches were investigated: a preliminary reaction in a mixture of cellulose, ethanol, and water, and a direct reaction within the molten PP matrix. The composites were thoroughly characterized using rotational rheometry, optical microscopy, differential scanning calorimetry, and dynamic mechanical analysis. Both methods resulted in composites with markedly reduced crystallinity and shrinkage compared to neat PP, with the lowest shrinkage observed in blends prepared directly in the extruder. The inclusion of cellulose not only enhances the environmental profile of these composites but also paves the way for the development of PP materials with improved biodegradability, highlighting the potential of this technique for fabricating more amorphous composites from crystalline or semi-crystalline polymers for enhancing the quality and dimensional stability of FDM-printed materials.

Much focus is being dedicated to the development of innovative technologies for producing biodegradable polymers from plant biomass. It is proposed that annual and perennial herbaceous plants, such as miscanthus, be used as promising sources of cellulose. The component composition of miscanthus allows us to consider it as a raw material for obtaining cellulose. This paper proposes methods for cooking miscanthus lignocellulose raw materials, which allow sulfate cellulose to be obtained with a high yield (up to 52%). In the process of obtaining chemical–thermomechanical pulp, the product yield is 71%. The possibility of replacing unbleached sulfate pulp with a semi-finished product from miscanthus for paper production is considered. For all types of raw materials obtained, acceptable paper-forming properties are observed. The best strength and deformation properties are obtained for sulfate cellulose. The addition of this cellulose to the composition of waste paper fluting significantly increases the sheet density, elasticity, and energy capacity without losing tensile strength. Using miscanthus raw materials along with waste paper of grade MS 5B makes it possible to make a composite product. The resulting products have optimal mechanical properties for creating the middle layer of corrugated cardboard. Miscanthus cellulose can be considered a promising raw material for enhancing waste paper fluting. Altering the system composition utilizing miscanthus and waste paper enables a broad modification of the mechanical and optical qualities of the resultant paper. The recommended concentration of miscanthus fraction in waste paper fluting is 30%.

In this study, polymer composites based on a polypropylene (PP) matrix with the addition of cellulose and ES-40, used as a silica precursor, were investigated. These composites were designed to achieve enhanced biodegradability through the incorporation of bioavailable cellulose and to enable subsequent carbonization into carbon–silicon carbide systems. Rheological investigations revealed that the multicomponent mixtures exhibited pseudoplastic behavior over the shear rate range typical of injection molding, ensuring process stability without additional plasticization. Morphological analysis demonstrated that an optimal balance of PP, cellulose, and ES-40 promoted the formation of a three-dimensional network structure, leading to a significant increase in flexural modulus at the equal flexural strength despite some reduction in tensile strength. It was further shown that substituting fibrous cellulose with microcrystalline cellulose improved the composite homogeneity, thereby enhancing the density and mechanical properties, especially in systems with low polymer contents. Preliminary pyrolysis experiments indicated that these injection-molded composites can serve as precursors for fabricating bulk thermally stable products containing silicon carbide particles. The obtained results underscore the high potential of the developed materials for applications in conventional injection molding, the possibility of additive manufacturing, and processes requiring subsequent carbonization.

Depending on the method of cellulose production, the proportion of alpha fraction in it can vary significantly. Paper pulp, unlike dissolving cellulose, has an alpha proportion of less than 90%. The presence of cellulose satellites in the system does not impede the formation of concentrated solutions of N-methylmorpholine-N-oxide (NMMO). In the current study, spinning solutions based on cellulose with a low alpha fraction (up to 90%) (pulp cellulose) are investigated. The morphological features and rheological behavior of such solutions are examined. It is suggested to roll the obtained solutions in order to obtain cellulose membranes. X-ray diffraction, IR spectroscopy, AFM and SEM were used to investigate the resulting structure and morphology of the obtained membranes. It is shown that the degree of crystallinity for the membranes varies based on the impurity content in the sample. The morphology of the films is characterized by a dense texture and the absence of vacuoles. The highest strength and elastic modulus were found for membranes made of bleached hardwood sulfate cellulose, 5.7 MPa and 6.4 GPa, respectively. The maximum values of the contact angle (48°) were found for films with a higher proportion of lignin. The presence of lignin in the membranes leads to an increase in rejection for the anionic dyes Orange II and Remazol Brilliant Blue R.

Cellulose and copolymers of acrylonitrile (PAN) are characterized by their chemical resistance to several conventional solvents. Therefore, these polymers are often used to obtain membranes for the recovery of such solvents. In this work, for the first time, composite membranes formed from highly concentrated mixed solutions based on cellulose and PAN are considered (the total content of polymers is 18 wt.%). For mixed solutions, the morphology and rheological behavior were evaluated. It is shown that the resulting solutions are two-phase, and their morphology depends on the components’ ratio and the system’s history. The non-monotonous change in the viscosity with the PAN content indicates a specific interaction of cellulose and PAN in N-methylmorpholine-N-oxide solutions. The rheological behavior of mixed solutions allows for their processing in conditions identical to those of cellulose solutions. The introduction of PAN into the cellulose matrix promotes a decrease in the structural order in the system, affecting the membranes’ transport properties. For composite membranes, it was found that with an increase in the content of the PAN phase, the retention of Remazol and Orange decreases, while the observed values are several times higher than those for cellulose membranes. The permeability of ethanol increases with increasing terpolymer content.

Applying surface modification routes to natural fibers is a practical option for solving the incompatibility problem in polymeric composites. This study aimed to improve the properties of biodegradable and environmentally friendly polybutylene succinate (PBS) composites involving flax fiber (FF) with unmodified, alkalization, and silanization surface modification applied at 20 wt%. The surface modifications were successfully characterized by FTIR and SEM. The composites were prepared using a twin‐screw extruder followed by injection molding. The mechanical, thermal, thermo‐mechanical, wear, water absorption, biodegradation, and morphological properties were evaluated. The incorporation of FF improved the mechanical and thermal performance of PBS, while the surface modifications further increased the fiber‐matrix adhesion. In particular, the silanized FF provided water resistance due to the hydrophobic nature of siloxane and exhibited the lowest biodegradation rate under fungal exposure. In the case of silanized FF, a 5.4% improvement in tensile strength and nearly 3% of water absorption capacity were reached. Based on these outcomes, the silanized FF‐filled PBS composite was suitable for packaging applications where biodegradable, water‐resistant, and mechanically strong materials are required.