Developing eco-friendly, high-performance fibers requires a deep understanding of the interplay between chemical and physical properties and processing conditions. Peracetic acid (PAA) pulping offers a sustainable alternative to conventional methods, decomposing into water and acetic acid, while providing higher selectivity for lignin removal and lower energy demand. This study aims to optimize PAA pulping conditions to maximize lignin removal while retaining hemicellulose and cellulose, thereby improving fiber quality for applications in biocomposites and paper products. PAA pulping was conducted under systematically varied conditions, with temperatures ranging from 70 to 90 °C and reaction times from 60 to 180 min at a 3 wt% solid load. The conditions were selected based on the reaction spectrum of PAA, which becomes feasible for pulping above 70 °C. To operate at atmospheric pressure and avoid excessive degradation, temperature was limited to 90 °C. The study (1) investigates the effect of these parameters on pulping efficiency, (2) evaluates chemical composition and structural changes through lignin content analysis, carbohydrate profiling, and fiber morphology characterization, and (3) determines mechanical performance through tensile testing of paper sheets before and after hot pressing. Optimal results at 80 °C for 120 min led to increased inter-fiber bonding (106.13 Nm/g), significant hemicellulose retention, and substantial lignin reduction. These findings underscore the potential of PAA pulping as an energy-efficient, sustainable method for producing tailored holocellulose fibers with applications in biocomposites and other renewable materials, highlighting a promising strategy for valorizing wood byproducts and reducing carbon emissions.

Feminine hygiene products, used by millions of women worldwide on a daily basis, come in various forms. Among them, tampons are a prominent type that aims to absorb menstrual blood directly in the vagina. However, the underlying mechanisms governing liquid absorption in tampons have received limited research attention and remain poorly understood. This study aims to investigate these mechanisms by examining the two main types of viscose fibres used in tampons and their effects when employed in tampon production. The sole distinction between the fibre types lies in their geometric shape—round or trilobal—while all other fibre parameters remain constant. To explore these mechanisms, tampon proxies made from these fibres were created and subjected to tests measuring liquid absorption. In addition, a novel method employing infrared thermography was utilized to infer the stored energy within the compressed tampon. Furthermore, individual fibres were characterised for chemical composition, surface properties, fine structure, liquid interaction, mechanical parameters, and friction behaviour. The results revealed that trilobal fibres exhibited higher tampon absorbency compared to their round counterparts, despite sharing similar chemical composition and comparable mechanical characteristics. This disparity can be attributed to the greater specific surface area of trilobal fibres, leading to enhanced liquid uptake through fibre swelling. However, single fibre swelling only accounted for a minor fraction of the total liquid absorbency of a tampon. The most influential fibre parameter was the geometric shape, as trilobal fibres facilitated the construction and maintenance of a bulkier network with increased available volume for liquid absorption. Graphic

The modification of lignocellulosic fibers through controlled swelling and impregnation plays a decisive role in tailoring their structure and reactivity for use in sustainable composite materials. In this study, holocellulose fibers were swollen in various solvents (sodium hydroxide at 2 and 4 wt% and ethanol–water mixtures at 0, 50, 70, and 100 wt%) to evaluate their impact on swelling and fiber characteristics. The pulp was produced with peracetic acid at 90 °C for 120 min from spruce wood chips and used for the swelling treatment. The fibers underwent swelling for 4 h in the different solvents, both without and with solubilized lignin at concentrations of 10 and 30 g/L, to investigate the impregnation ability of the fibers for lignin as a natural binder. Fiber morphology, lignocellulosic composition, and liquid retention values were analyzed to assess the effects of solvent–binder interactions on fiber swelling and lignin uptake. The results revealed significant differences in fiber characteristics influenced by both solvent choice and lignin presence, demonstrating the feasibility and optimization potential of a single-step swelling-impregnation process. These findings highlight key factors that can improve the uptake of natural binders in wood fibers, offering insights for effective fiber preconditioning in composite production.

Tampons are widely used hygiene products, yet there remains a lack of engineering-focused research on their design and functionality. A critical factor in tampon performance is the pore structure of the material, which directly influences liquid absorption. While micro-computed tomography has provided valuable insights into overall pore volume, it falls short in accurately characterizing individual pore sizes. In this study, we employ the sub-network of an over-segmented watershed (SNOW) algorithm alongside PoreSpy to obtain a detailed pore size distribution within tampon proxy materials. Our findings reveal that tampon proxies made of trilobal cellulose viscose fibres exhibit significantly larger pores, with a 26-32% higher pore equivalent diameter (PED), than their round-fibre counterparts, despite comparable porosity, highlighting the influence of fibre geometry on expansion and liquid uptake. Although trilobal CV tampon proxies exhibit a 41% greater expanded volume and 18.7% higher absorbency compared to round fibres, their porosity increases only moderately, underscoring the need to investigate pore structure beyond bulk metrics. Kolmogorov–Smirnov distance analyses confirm that inter-fibre differences in pore structure exceed intra-sample variations, underlining the dominant role of fibre type on absorbency. While gradients along the tampon proxy length influence local pore formation, trilobal fibre tampon proxies consistently form larger pores, enhancing their liquid absorption properties. Additionally, we observe a systematic increase in pore size from top to bottom, likely influenced by one-sided liquid application and compression effects during production. These results offer a more detailed understanding of the mechanisms governing pore formation in tampon networks and provide a basis for future simulations of liquid imbibition, ultimately contributing to optimized tampon designs

Achieving the simultaneous integration of thermal insulation, mechanical robustness, hydrophobicity, and intrinsic flame retardancy in bio‐based porous materials remains a major challenge. Here, we report a hierarchically engineered nanocomposite foam composed of nanofibrillated cellulose (NFC), alkyl ketene dimer (AKD), and halloysite nanotubes (HNT), designed via a multiscale structure–property approach. Incorporation of HNT (1–10 wt%) reinforces the fibrillar network and introduces a hierarchical macro–mesoporous architecture, while AKD imparts durable hydrophobicity with water contact angles of 133–154°. The foams exhibit low thermal conductivity (0.031–0.046 W m ^{− 1} K ^{− 1} ), high compressive modulus (∼1.1 MPa), and excellent deformability (∼80% strain). The materials display outstanding flame retardancy, with combustion velocities reduced by over an order of magnitude (∼6 to ∼0.1 cm s ^{− 1} ) and clear self‐extinguishing behavior. Thermal analysis reveals enhanced stability and increased char yield (∼45%), consistent with modified degradation pathways. Thermal cycling tests (10 cycles, 25°C–80°C) confirm structural stability with no pore collapse and negligible change in thermal conductivity (≤2.2%). This multifunctionality arises from the synergy between halloysite‐induced barrier effects, hierarchical structural reinforcement, and controlled interfacial chemistry, providing a scalable route to sustainable, lightweight, and fire‐safe insulation materials without toxic additives.