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Pyrolysis is a promising way to reuse of waste tires. However, the carbon black generated in the process is often contaminated with various pyrolysis products. This study aims to recycle low-quality recycled carbon black (rCB) from waste tire pyrolysis, addressing the challenges posed by organic residues (up to 5 wt% bituminous substances, 112.2 mg/kg PAH). This causes the agglomeration of particles and decreases the active specific surface area. Cavitational vortex milling (both wet and dry) emerges as a promising method to valorize contaminated rCB, allowing for a significant reduction in the concentration of contaminants. This novel method allows for the generation of hydrophilic and hydrophobic black pigments. In parallel experiments, low-quality rCB is incorporated into solid biofuel to enhance its calorific value. The addition of 10 wt% rCB) to peat residues significantly elevates the calorific value from 14.5 MJ/kg to 21.0 MJ/kg. However, this improvement is accompanied by notable increases in CO2 and SO2 emissions. This dual effect underscores the necessity of considering environmental consequences when utilizing recycled carbon black as a supplement to solid biofuels. The findings provide valuable insights into the potential of cavitational vortex milling for carbon black valorization and highlight the trade-offs associated with enhancing biofuel properties through the addition of rCB.

Water, alcohols, diols, and glycerol are low-cost blowing agents that can be used to create the desired silicone foam structures. Although their combined use can be beneficial, it remains unclear how it affects the physical properties of the resulting materials. We conducted a comparative study of these hydroxyl-bearing blowing agents in fumed silica- and mica-filled polymer composite systems for simultaneous blowing and crosslinking to obtain a low-density, uniform porosity and superior mechanical properties. The foams were optimized for a uniform open-pore structure with densities ranging from 75 to 150 kg‧m−3. Varying the diol chain length (Cn) from one to seven carbons can alter the foam density and structure, thereby enhancing the foam tensile strength while maintaining a low density. Replacing 10 mol% of water with 1,4-butanediol decreased the density by 26%, while increasing the specific strength by 5%. By combining glycerol and water blowing, the resulting foams exhibited a 30% lower apparent density than their water-blown analogs. The results further showed that Cn > 4 alkane chain diols had an odd–even effect on the apparent density and cell wall thickness. All foamable compositions had viscosities of approximately 7000 cSt and curing times below 2 min, allowing for quick dispensing and sufficient time for the foam to cure in semi-industrial volumes.

The effect of CO2 laser treatment on the surface composition and properties of a woven fabric (polyester (PET) fiber (59 wt%)/cotton (CO) fiber (31 wt%)/stainless-steel (SS) metal fibers (10 wt%)) was investigated across a range of laser intensities (19.1 × 106 to 615.0 × 106 W/m2). Elemental analysis using wavelength-dispersive X-ray fluorescence (WD-XRF) revealed that for an intensity up to 225.4 × 106 W/m2, the carbon content on the fabric surface increased while the oxygen content decreased, indicating thermally induced surface modification. Fourier transform infrared (FT-IR) spectroscopy confirmed that no new chemical bonds were formed, suggesting that the changes observed were predominantly physical in nature. High-resolution scanning electron microscopy (HR-SEM) showed progressive fiber fusion and surface smoothing with increasing laser intensity, consistent with polyester melting. Tensile testing demonstrated a significant decline in peak load and elongation at peak load with rising laser fluence, indicating mechanical embrittlement. Overall, CO2 laser treatment alters the morphology and elemental composition of the fabric surface without inducing major chemical decomposition, markedly reducing its mechanical strength.

Modifications of pore size distribution and structural order of nanoporous carbide-derived carbon (CDC) materials with variety of surface areas and pore sizes were investigated using physical activation by etching with water vapour. Variable etching duration was used to explore the activation impact on the pore size distribution and the adsorption behaviour of TiC-derived carbon. A distribution of micro- and mesopores, modified during physical activation, was studied using N 2 and CO 2 adsorption. Notable impact of preceding carbon structure on the activation product was revealed by the results of scanning electron microscopy, powder X-ray diffraction and Raman spectroscopy. An infrared spectroscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy confirmed that water-induced etching of CDC followed by high-temperature treatment in inert gas atmosphere does not change notably the total amount of surface oxygen, however, leads to the changes in a composition of oxygen containing functional groups in post-activated carbon. The electrochemical evaluation was performed in triethylmethylammonium tetrafluoroborate/acetonitrile electrolyte to elaborate the structure-electrochemical properties relationships on post-activated nanoporous CDC materials. It was observed that the degree of improvement in double-layer capacitance achievable with a steam-treatment significantly depends on the preceding properties of CDC prior treatment, whereby the highest capacitance, ~ 160 Fg −1 , was reached for the steam-treated TiC-derived CDC made at 800 °C, which clearly is a very promising material for the electrical double-layer capacitor.

The present study considers TiC-derived carbon (CDC) and its partially oxidized derivative (ox-red-CDC) as potential electrode materials for pH-neutral aqueous electrolytes. The CDC was converted to ox-red-CDC by a modified Hummers’ method involving back-reduction with hydrogen at 800 °C. Oxidation degraded the graphitic CDC structures, as shown by X-ray diffraction analysis, while scanning electron microscopy confirmed the exfoliation of graphene layers on the oxidized carbon surface. The changes in the surface chemistry of the carbon materials were studied by infrared, X-ray photoelectron, and energy-dispersive X-ray spectroscopy. The gas adsorption analysis showed a slight decrease in the volume of the subnanometer-sized pores during oxidation/reduction of CDC. To elucidate the relationships between the structure and electrochemical properties of carbon materials, cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy measurements were performed in 1 M Na2SO4 using 2- and 3-electrode test cells. The highest capacitance of 163 F g−1 was demonstrated by pristine TiC-derived CDC in a symmetric 2-electrode cell. The asymmetric cell, which contained ox-red-CDC as an anode and pristine CDC as a cathode, had a slightly lower capacitance but an excellent cycling lifetime (specific capacitance increased by 7% after 5000 cycles). Temporary repolarization of 2-electrode cells during cycling improved both capacitance and power characteristics.Graphical abstract

Even though enehydrazide moiety is present in many pharmaceuticals, there is currently no straightforward method available for preparing cyclic enehydrazides, which could be valuable building blocks in anticancer research. Herein, we report how electronic effects and ring size influence the direction and yield of Ru catalytic carbon–carbon double bond isomerization in heterocyclic enehydrazines. Having the knowledge of how variation of these properties affects the equilibrium between double bond isomers enables us to control the outcome when preparing different cyclic enehydrazides. Six enehydrazide heterocycles and five enehydrazine heterocycles were synthesized and characterized with the current method. In addition, cytotoxicity evaluation of the synthesized compounds showed that several heterocycles produced in this study could be used in developing anticancer drugs.

Plant resource sharing mediated by mycorrhizal fungi has been a subject of recent debate, largely owing to the limitations of previously used isotopic tracking methods. Although CdSe/ZnS quantum dots (QDs) have been successfully used for in situ tracking of essential nutrients in plant-fungal systems, the Cd-containing QDs, due to the intrinsic toxic nature of Cd, are not a viable system for larger-scale in situ studies. We synthesized amino acid-based carbon quantum dots (CQDs; average hydrodynamic size 6 ± 3 nm, zeta potential −19 ± 12 mV) and compared their toxicity and uptake with commercial CdSe/ZnS QDs that we conjugated with the amino acid cysteine (Cys) (average hydrodynamic size 308 ± 150 nm, zeta potential −65 ± 4 mV) using yeast Saccharomyces cerevisiae as a proxy for mycorrhizal fungi. We showed that the CQDs readily entered yeast cells and were non-toxic up to 100 mg/L. While the Cys-conjugated CdSe/ZnS QDs were also not toxic to yeast cells up to 100 mg/L, they were not taken up into the cells but remained on the cell surfaces. These findings suggest that CQDs may be a suitable tool for molecular tracking in fungi (incl. mychorrhizal fungi) due to their ability to enter fungal cells.

Atomic Layer Deposition (ALD) has been investigated for the possible protection of various materials against atomic oxygen (ATOX) at ESTEC Materials and Electrical Components Laboratory facility. ALD is a conformal coating process, that can be used to apply ultra-thin films of metal oxides on various materials, that may have a sophisticated three-dimensional shape, such as the internal and external components of satellites. The challenge with metal oxides on soft and/or flexible surfaces arises from the brittle nature of these ceramic films if their thickness exceeds 30 nm. Different substrates, including silicon, Printed Circuitry Board (PCB), polyimide, and Carbon Fibre Reinforced Polymers (CFRP) were coated by ALD with 20 nm thick metal oxide films at 125 °C, then exposed to ATOX and characterized by photographing, reflectance measurement and scanning electron microscopy (SEM). The studies showed good performance of protective films prepared by ALD on polymer substrates, which suggests that the nanometer-scale coatings can improve the lifetime of these materials at low Earth orbit, where they are inevitably exposed to ATOX. In contrast, the uncoated substrates suffered near-surface damage after exposure to ATOX, which resulted in microscopic features on their surface that were visible in SEM. Damage caused by ATOX to the uncoated substrates was also visible in photographs and observable in reflectance studies. In the latter case, the changes in the reflectance spectrum were caused by the change of surface morphology and/or chemical and elemental composition due to corrosion by ATOX.

Double bond isomerization by in situ generated ruthenium hydride catalyst in 6- to 9-membered hydrazine heterocycles including an endocyclic N–N bond was investigated. Based on the results of the experiments, a conclusion was made that the generation of resonance-stabilized enehydrazides is generally favored, but in some cases, the reaction pathway is presumably also highly dependent of steric interactions. With the current method, two novel enehydrazide heterocycles and one enehydrazine heterocycle were produced and characterized.

Hydrophobic silica aerogel powder and hollow glass microspheres (HGM) were used as fillers for an epoxy adhesive to improve its thermal insulator properties. At 50 wt% of HGM content, the thermal conductivity of the HGM/epoxy composite decreased from 0.182 W/mK to 0.104 W/mK. The aerogel/epoxy composite, on the contrary, showed a slight increase in its thermal conductivity, most probably due to the filling of aerogel pores with the epoxy adhesive. Furthermore, it was shown that adhesion values of epoxy composites increase with the addition of aerogel and decrease when HGM was used as the filler material. Realistic numerical finite element method simulations revealed an increase in thermal isolation properties for both HGM/epoxy and aerogel/epoxy composites.