This study introduces a ternary composite system based on silicone, carbon black (CB), and liquid metal (LM) gallium. Despite extensive studies on LM/elastomer systems, most have primarily focused on mechanical reinforcement or thermal conductivity, while a systematic understanding of their electrical modeling and electromagnetic shielding performance remains insufficient. Therefore, we utilized silicone as an elastomeric matrix, CB as conductive nanofillers, and gallium as a conductive metallic phase, a flexible composite with enhanced multifunctional performance is realized. Shear dispersion during fabrication induces a unique star-like architecture of gallium, which, together with the conductive CB network, facilitates the formation of efficient and continuous electrical pathways. The resulting composites exhibit notable improvements in mechanical strength, strain-dependent resistive response, and electromagnetic interference (EMI) shielding capabilities. In particular, the optimized composite achieves an EMI shielding effectiveness of ∼35 dB in the X-band, while maintaining stable strain sensing performance over 1000 cycles at 30 % strain. A systematic investigation into the influence of gallium concentration elucidates the correlation between microstructural evolution and the composite’s physical and electromagnetic behavior. This work not only deepens the understanding of LM-based ternary composites but also highlights their potential for advanced applications in flexible sensing, wearable electronics, and EMI attenuation technologies.

In this study, a two-stage, low-consistency (LC) refining process at the Holmen Braviken paper mill in Sweden was examined to evaluate the relationship between energy input, fibre distributions, and pulp properties, including handsheet properties. The LC refiners used thermo-mechanical pulp based on 100 % Norway spruce, with two specific energy levels: "low" (approximate to 80 kWh/adt) or "high" (approximate to 100 kWh/adt). All four permutations of these settings were examined. Overall, higher refining efficiency (measured by the increase in tensile index per applied energy) was observed in the first LC refiner stage than in the second. To further explore the impact of LC refining, pulp particle distributions were investigated. Samples from before, between and after the two LC stages were analysed using an optical fibre analyser, which provided detailed data on length-width-curl-fibrillation distributions. The impact of LC refining on these distributions was quantified using Kolmogorov-Smirnov statistics, highlighting statistically significant changes observed in the length and curl distributions. We investigated the correlation between energy input into the LC refiners and the impact on fibre distributions and handsheet properties. These insights underscore the effectiveness of our analytical approach and its potential for refining process control in mechanical pulping, offering a method for more targeted and efficient adjustments.

Water-soluble polymers are materials rapidly growing in volume and in number of materials and applications. Examples include synthetic plastics such as polyacrylamide, polyacrylic acid, polyethylene glycol, polyethylene oxide and polyvinyl alcohol, with applications ranging from cosmetics and paints to water purification, pharmaceutics and food packaging. Despite their abundance, their environmental concerns (e.g., bioaccumulation, toxicity, and persistence) are still not sufficiently assessed, especially since water soluble plastics are often not biodegradable, due to their chemical structure. This review aims to overview the most important water-soluble and biodegradable polymers, their applications, and their environmental impact. Degradation products from water-insoluble polymers designed for biodegradation can also be water soluble. Most water-soluble plastics are not immediately harmful for humans and the environment, but the degradation products are sometimes more hazardous, e.g. for polyacrylamide. An increased use of water-soluble plastics could also introduce unanticipated environmental hazards. Therefore, excessive use of water-soluble plastics in applications where they can enter the environment should be discouraged. Often the plastics can be omitted or replaced by natural polymers with lower risks. It is recommended to include non-biodegradable water-soluble plastics in regulations for microplastics, to make risk assessments for different water-soluble plastics and to develop labels for flushable materials.

This study examined the high-temperature stability of polyether ether ketone (PEEK) and polyphenylene sulfide (PPS) in an oxygenated environment. Both polymers were extrusion-coated onto copper wires for electrical insulation in traction motors. Accelerated testing using thermogravimetry and calorimetry showed that copper catalyzed thermal oxidation of PEEK (at very high temperature), which was accelerated by a lower molar mass of the PEEK and an increased copper-polymer contact area. Both techniques indicated a complex thermal oxidation pattern for both polymers. Notably, the presence of copper seemed to reduce/retard the degradation of PPS. Overall, both polymers demonstrated high oxidation resistance at elevated temperature in an air environment, indicating long service life in electric motor, excluding factors like moisture, oil spray cooling and Joule heating.

The study demonstrates a scalable and reproducible method for synthesising graphene oxide (GO) nanosheets from commercial carbon fibres derived from carbonised polyacrylonitrile (PAN) polymer. An exfoliation route with nitric acid allows for the preparation of monolayer GO nanosheets with a consistent thickness of 0.9 ± 0.2 nm, identical to the commercially available GO from mined graphite. The GO nanosheets exhibit distinct circular and elliptical shapes, in contrast to the polygonal and sharp-edged morphology of commercial GO. An extensive evaluation of acidic solutions and electrical potentials identified a narrow processing window critical for obtaining GO nanosheets sized 0.1–1 µm. An unexpectedly low 5% acid concentration was found to be the most effective, providing a balance between efficient exfoliation through synergistic acidic and electrochemical oxidation. The process provides a high yield of 200 mg of GO per gram of carbon fibre. Advanced characterisation using high-resolution electron and atomic force microscopy (HR-TEM/SEM/AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (FTIR) provided detailed insights into the morphology, thickness, surface functionalisation, and chemical composition of the nanosheets. With its high yield, environmentally sound production, and versatility, the synthesised GO offers transformative potential for large-scale applications, including energy storage, advanced coatings, high-performance composites, water purification, and electronic devices.

We here report the properties of polyether ether ketone (PEEK) loaded with hexagonal boron nitride (BN) with and without aluminum nitride (AlN), produced through extrusion compounding and compression molding. The primary purpose of this work was to improve the thermal conductivity of PEEK for electric insulation applications in electric motors. The thermal conductivity, thermal diffusivity, and effusivity increased with filler content reaching maximum values at 30 wt % filler that were a factor of approximately 2, 2, and 1.5 of those of the pure polymer. On a volume content, the ternary system PEEK/BN/AlN was more effective than the binary system (PEEK/BN) in raising the thermal conductivity. By the use of a developed model, it was possible to conclude that a small synergy in terms of thermal conductivity did exist. Density revealed compact systems with a porosity of 0–3%. Scanning electron microscopy revealed a uniform dispersion of BN and a combination of dispersed AlN nanoparticles and agglomerates in the ternary system. Dielectric and breakdown voltage results indicated that the composite properties were acceptable for electric motors, even though the DC breakdown strength decreased in the presence of the fillers.

This study focuses on the development of a compact model with improved interpretability compared to similar approaches, relating thermomechanical pulp (TMP) properties, quantified using a fiber analyzer, to Canadian standard freeness and handsheet properties. The data used in this study are obtained from TMP produced by a conical disc refiner. Utilizing the LASSO-regularized Latent Variable Regression (LASSO-LVR) model, we identified three key latent variables – representing shives content, fibrillation, and slender fines content – that accurately predict eight distinct handsheet properties. In a subsequent analysis, we investigated the linkage between refiner settings and Specific Refining Energy (SRE) to these key analyzer readings and, consequently, to handsheet properties. The inclusion of SRE as an internal state variable in the model significantly enhanced predictive accuracy, providing a foundation for more precise and energy-efficient control strategies in refining processes.

Improving the mechanical properties of wood and paper is crucial for enhancing their performance in structural and packaging applications. A particularly effective method for increasing strength is hot-pressing, where lignin softening has been proposed as a key mechanism underlying improved fiber bonding. In this study, we investigated the deformation behavior of Norway spruce lignin across temperatures of approximately 25-300 °C and moisture contents of 0-25 wt % using molecular dynamics simulations and paper hot-pressing experiments. We simulated key mechanical paper properties, including Young's modulus, glass transition temperature, and the diffusivity of water and lignin chains. Experimental results showed a pronounced increase in wet strength above 175 °C, which correlated with lignin softening and enhanced fiber-fiber bonding in the simulations. Our findings highlight the ability of molecular simulations to elucidate the mechanisms of lignin-driven bonding and provide a foundation for optimizing the use of lignin-rich materials in various applications.

This study investigates the size-dependent mechanical properties of electrospun polycaprolactone (PCL) nanofibers by analyzing the relationship between fiber diameter and Young's modulus. Experimental data reveal a clear inverse trend: as fiber diameter decreases, stiffness increases significantly, indicating strong surface and confinement effects at the nanoscale. Two theoretical models were employed to interpret the observed behavior: a simplified core–shell model (Model 1) and an extended model (Model 2) incorporating surface tension and curvature elasticity. Both models accurately fit the experimental data across a diameter range of 450–850 nm, with Model 2 providing slightly better agreement at intermediate diameters (∼600–750 nm), where surface mechanics become more prominent. The enhanced stiffness in thinner fibers is attributed to increased surface-to-volume ratio and tighter molecular packing, while larger fibers exhibit bulk-dominated mechanical responses. These findings highlight the importance of nanoscale geometry and surface effects in determining mechanical properties and suggest that fiber stiffness can be systematically tuned via diameter control during electrospinning.

This study introduces a new semi-empirical power-law model for predicting electrospun fiber diameter (D), addressing key processing parameters. Polycaprolactone (PCL) fibers were produced using a solvent mixture of Trichloromethane (TCM), Dimethyl Formamide (DMF), and ethanol (EtOH). Systematic experiments validated an existing theoretical model and led to the development of a novel model: D ∼ (c1/2η1/3Q1/5X2/3)/(U2/3ω1/4I1/5). This model incorporates seven crucial parameters: viscosity (η), concentration (c), voltage (U), spinning distance (X), flow–rate (Q), current (I) and collector wheel rotation speed (ω). The model was validated through a partial factorial design experiment, proving to be a valuable and reliable tool for predicting fiber diameters and optimizing electrospinning processes. The ability to control fiber diameter is essential for tailoring electrospun fibers for various applications, including biomedicine, filtration, sensors, and lightweight materials.