Unmodified Samples Research Articles

A fire‐safe, single‐component epoxy resin based on a phosphorus/imidazole‐containing latent curing agent and diphenylphosphine

AbstractThis work reported a flame‐retardant, single‐component epoxy resin (EP) via introducing diphenylphosphine (DPP) and benzimidazolyl‐substituted cyclotriphosphazene (BICP) into EP. The differential scanning calorimetry (DSC) test showed that the onset curing temperature of DPP/BICP‐15/10 was 50°C lower than that of BICP‐12 due to the catalytic decomposition effect of DPP toward BICP under heating. Besides, the shelf life of DPP/BICP‐15/10 at room temperature reached ~14 days, demonstrating good storage stability. EP/DPP/BICP maintained satisfactory thermal properties and showed excellent flame retardancy with a UL‐94V‐0 classification. Compared with the unmodified EP sample, the peak heat release rate (PHRR) and total heat release (THR) of DPP/BICP‐15/13 were decreased by ~68.1% and ~55.1%, respectively. Hence, this flame‐retardant, single‐component epoxy resin with satisfactory comprehensive properties exhibited great potential for versatile industrial applications.

Decorating carbon quantum dots onto VO2 nanorods to boost electron and ion transport kinetics for high–performance zinc–ion batteries

Rechargeable aqueous Zn–ion batteries (RAZIBs) are regarded as attractive alternatives for large–scale energy storage. V–based cathode materials have gained great attention due to the merits of rich valence states, controllable morphology, diverse crystal structures, and controllable chemical compositions. However, the development of high–performance V–based cathode is still impeded by sluggish electron/ion transport kinetics. To address this issue, this work reveals that the electrochemical performance of the VO2 cathode can be significantly boosted by decorating carbon quantum dots (CQDs) onto the VO2 nanorods via a facile hydrothermal reaction. The VO2/CQDs sample is characterized to have strong interface interaction with the presence of CO bond. Compared to the CQD–free counterpart, the obtained VO2/CQDs sample exhibits higher specific surface area (18.7 vs 4.4 m2 g−1), better electrolyte wettability (53° vs 114° for contact angle), reduced charge–transfer resistance (1.8 vs 19.9 Ω), and facilitated ion diffusion coefficient (1.66 × 10−10 vs 4.56 × 10−11 cm2 s−1). Benefiting from these features, a high attainable capacity of 427 mAh g−1 at 0.2 A g−1 can be reached for VO2/CQDs, corresponding to the specific energy of 333 Wh kg−1 (based on the mass of VO2/CQDs). When the current density increases to 8 A g−1, VO2/CQDs can still deliver 309 mAh g−1, showing great promise for high–rate capability. Moreover, the VO2/CQDs cathode renders stable cycle performance with retaining 229 mAh g−1 after 2000 cycles. By contrast, the unmodified sample demonstrates moderate electrochemical performance (373 and 186 mAh g−1 at 0.2 and 8 A g−1, respectively). The results highlight the importance of the CQDs decoration strategy, which can effectively boost electron/ion transport in oxide–based cathodes for high–performance RAZIBs.

Adsorption, Modeling, Thermodynamic, and Kinetic Studies of Acteray Golden Removal from Polluted Water Using Sindh Clay and Quartz as Low-Cost Adsorbents

Due to growing environmental awareness and demands, many efforts were implemented for the transformation of waste materials into highly efficient adsorption capacity materials. In this work, efforts were made to convert the Sindh clay and quartz into an efficient composite for dye removal from polluted water. The synthesized composites were characterized using FT-IR, BET, SEM, and XRD. The synthesized composite showed a crystalline structure with specific characteristics, including a specific surface area of 7.20 m2/g and a pore diameter of 3.27 nm. The formation of iron cyanide hydrate (2030 cm−1) and iron oxides (418 cm−1) were depicted through Fourier transform infrared spectroscopy analysis. The micrographs obtained show that the unmodified quartz sample has a flattened and elongated shape compared to the modified quartz sample, which has aggregated and coarse morphology. The effects of several factors, such as temperature, contact time, and initial dye concentration, were studied. Kinetic models were also applied to determine the probable route of the adsorption process. For adsorption equilibrium analysis, the Dubinin–Radushkevich, Langmuir, Freundlich, Temkin, and Harkin–Juraisotherm models were employed. The Freundlich isotherm model and pseudo-first-order model best described the adsorption of dyes onto the clay composites. R2 values were close to 1 or more than 0.9, showing which equation fits the experimental data. The produced composite demonstrated good reusability, maintaining over 90% of the adsorption capacity after five reaction cycles without the need for reactivation.

Water Vapor Sorption Kinetics of Beech Wood Modified with Phenol Formaldehyde Resin Oligomers

Beech is an important tree species in Europe. This study aimed to elucidate the influence of four molecular weights of phenol formaldehyde (PF) resin (266, 286, 387, and 410 g/mol) on the sorption behavior of unmodified and modified beech wood samples using a dynamic vapor sorption (DVS) apparatus. The variations in the environmental relative humidity and moisture content (MC) of the samples were recorded, and the DVS isotherms were plotted from the equipment. During the sorption process, the MC of the modified samples decreased in comparison to that of the unmodified samples, and both apparently decreased with the increasing molecular weight of the PF resin. The DVS isotherm hysteresis plot illustrated a reduction in sorption hysteresis for the modified wood with varying PF resins compared to the unmodified samples. Based on the DVS isotherm adsorption and desorption plots, the decrease in the equilibrium of the MC can be attributed to there being fewer sorption sites in the modified samples, which exhibited the lowest hygroscopicity. Overall, the moisture sorption mechanism for both types of samples was clarified, highlighting a clear correlation between the molecular weight of the applied PF resin and its influence on moisture sorption behavior.

Thermochemical modification of beech wood with ammonium hydroxide

Four variants of the thermochemical modification were conducted on beech wood at a temperature of 130 °C, employing NH4OH concentrations of 5% or 10% for durations of either 12 or 24 h. The weight% gain (WPG) and bulking coefficient (BC) were initially calculated. Subsequently, the wood’s degree of discoloration was assessed using the CIELAB-colour-system. Chemical structure alterations were determined through Fourier transform infrared spectroscopy (FTIR), while the compressive strength of the wood parallel to the grain was measured. As the NH4OH concentration increased and the treatment duration extended, the samples displayed simultaneous weight increase and volume reduction. The ΔE* values of the samples ranged from 19.33 to 21.09 units, indicating significant color alteration. FTIR analysis revealed differences between the spectra of the unmodified control sample and the NH4OH-treated samples. The modification reduced in hydroxyl and carboxyl groups within the main and side chains of hemicelluloses. Additionally, a decrease in the absorption peak intensity of the unconjugated carbonyl group at 1740 cm− 1 indicated a relative reduction in hemicellulose content. Compressive strength tests showed that the thermochemical modification improved the modulus of elasticity, increasing it from 10,898 MPa (in the control sample) to a range of 11,663 − 13,390 MPa. Similarly, the compressive strength increased from 77.10 MPa to 81.56-107.19 MPa. Interestingly, this improvement was more pronounced with higher concentrations of NH4OH and prolonged modification durations.

Synergistic effect of enzymatic pre-treatment and amylose–lipid complex construction on the physicochemical properties of maize starch

In this study, the effects of maltogenic amylase (MAA) pre-treatment and starch–fatty acid complex construction on the physicochemical properties of maize starch (MAS) were investigated. The average chain length of MAA-modified MAS was found to decrease from 18.15 to 14.92. Moreover, MAA pre-treatment of starch induced the formation of a V-type complex. This behaviour was demonstrated by the higher diffraction intensity, enzymatic resistance and short-range ordering of the samples pre-treated with MAA compared with unmodified samples. X-ray diffraction and rheological analysis revealed that the re-crystallisation peak intensities and storage modulus of MAA–MAS–lauric acid (LA)/stearic acid (SA) complexes were lower than those of MAA–starches, MAS–LA/SA complexes and control. The rate of starch re-crystallisation was effectively decreased by the combination of MAA pre-treatment and V-type complex construction. The anti-retrogradation (long-term) characteristics of the tested samples were in the following order: MAA–MAS–LA/SA complexes > MAA–starches > MAS–LA/SA complexes > control.

Direct methanol fuel cell with enhanced oxygen reduction performance enabled by CoFe alloys embedded into N-doped carbon nanofiber and bamboo-like carbon nanotube

The exploration of cost-effective electrocatalysts with high catalytic activity and methanol tolerance to replace precious metal catalysts in the oxygen reduction reaction (ORR) is highly desirable for direct methanol fuel cells (DMFCs). Herein, we report a novel complex composed of a CoFe alloy with a modulated electronic structure confined to nitrogen-doped carbon nanofiber (NCNF) and bamboo-like carbon nanotube (BCNT) by tuning the molar ratio of Co and Fe (CoFe@NCNF/BCNT). The synthetized catalysts possess one-dimensional (1D) mesoporous structure, high specific surface area, and rich pyridinic-N content. Notably, the Co1Fe1@NCNF/BCNT and Co1Fe3@NCNF/BCNT (Co:Fe ≈ 1:1 and 1:3) exhibited enhanced oxygen reduction activity and methanol tolerance, compared to unmodified samples. In addition, alkaline DMFCs containing Co1Fe1@NCNF/BCNT and Co1Fe3@NCNF/BCNT presented high power density (29.10 and 31.11 mW cm−2), exceeding that of Pt/C-modified DMFC (27.23 mW cm−2). Furthermore, the Co1Fe1@NCNF/BCNT-catalyzed DMFC exhibited high stability. This improved catalytic activity can be attributed to the rich surface area, controllable alloy composition, optimized N configuration, and favorable electronic interaction. The as-developed CoFe@NCNF/BCNT with multifunctional components may open a new avenue for designing highly active cathode catalysts for various fuel cells.

Cyclic potentiodynamic passivation of 316L stainless steels of different crystallographic orientation produced by laser powder bed fusion: Towards the improvement of corrosion resistance

AbstractThe influence of cyclic potentiodynamic passivation (CPP) of 316L stainless steels (SS) of different crystallographic orientation produced by laser powder bed fusion (LPBF) on the resulting general and pitting corrosion resistance is discussed. CPP was performed by cyclic voltammetry in aqueous 0.1 M NaNO3. Electrochemical tests including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and linear potentiodynamic polarization were employed to evaluate the resulting corrosion properties of the surfaces in aqueous 3.5 wt.% NaCl. It was found that the CPP method enables the formation of a passive oxide surface film which significantly improved the materials' general and pitting corrosion resistance in comparison to the naturally‐formed passive film under the experimental conditions investigated. It was also found that the general corrosion resistance, for both the unmodified (naturally‐passivated) and CPP‐modified LPBF 316L samples, decreased in the order of {111} > {100} > polycrystalline > {110}. Although the CPP‐modified samples showed a significantly lower current in the passive region and higher pitting potentials, in comparison to the unmodified samples, their crystalline structure was found not to have any influence on the corresponding behaviours.

Biomimetic Copper Forest Structural Modification Enhances the Capillary Flow Characteristics of the Copper Mesh Wick

In a two-phase heat transfer device, achieving a high capillarity of the wick while reducing flow resistance within a limited space becomes the key to improving the heat dissipation performance. As a commonly used wick structure, mesh is widely employed because of its high permeability. However, achieving the desired capillary performance often requires multiple layers to be superimposed to ensure an adequate capillary, resulting in an increased thickness of the wick. In this study, an ultra-thin biomimetic copper forest structural modification of copper mesh was performed using an electrochemical deposition to solve the contradiction between the permeability and the capillary. The experiments were conducted on a copper mesh to investigate the effects of various conditions on their morphology and capillary performance. The results indicate that the capillary performance of the modified copper mesh improves with a longer deposition time. The capillary pressure drops can reach up to 1400 Pa when using ethanol as the working fluid. Furthermore, the modified copper mesh demonstrates a capillary performance value (ΔPc·K) of 8.44 × 10−8 N, which is 1.7 times higher than that of the unmodified samples. Notably, this enhanced performance is achieved with a thickness of only 142 μm. The capillary limit can reach up to 45 W when the modified copper mesh is only 180 μm. Microscopic flow analysis reveals that the copper forest modified structure maintains the original high permeability of the copper mesh while providing a greater capillary force, thereby enhancing the overall flow characteristics.

Imaging of CO2 and Dissolved Inorganic Carbon via Electrochemical Acidification-Optode Tandem.

Dissolved inorganic carbon (DIC) is a key component of the global carbon cycle and plays a critical role in ocean acidification and proliferation of phototrophs. Its quantification at a high spatial resolution is essential for understanding various biogeochemical processes. We present an analytical method for 2D chemical imaging of DIC by combining a conventional CO2 optode with localized electrochemical acidification from a polyaniline (PANI)-coated stainless-steel mesh electrode. Initially, the optode response is governed by local concentrations of free CO2 in the sample, corresponding to the established carbonate equilibrium at the (unmodified) sample pH. Upon applying a mild potential-based polarization to the PANI mesh, protons are released into the sample, shifting the carbonate equilibrium toward CO2 conversion (>99%), which corresponds to the sample DIC. It is herein demonstrated that the CO2 optode-PANI tandem enables the mapping of free CO2 (before PANI activation) and DIC (after PANI activation) in complex samples, providing high 2D spatial resolution (approx. 400 μm). The significance of this method was proven by inspecting the carbonate chemistry of complex environmental systems, including the freshwater plant Vallisneria spiralis and lime-amended waterlogged soil. This work is expected to pave the way for new analytical strategies that combine chemical imaging with electrochemical actuators, aiming to enhance classical sensing approaches via in situ (and reagentless) sample treatment. Such tools may provide a better understanding of environmentally relevant pH-dependent analytes related to the carbon, nitrogen, and sulfur cycles.

Transparent Silicone–Epoxy Coatings with Enhanced Icephobic Properties for Photovoltaic Applications

Recently, the photovoltaic technology has become very popular as a means to produce renewable energy. One of the problems that are still unsolved in this area of the industry is that photovoltaic panels are subject to a significant loss of efficiency due to the accumulation of dust and dirt. In addition, during the winter season, the accumulation of snow and ice also reduces or stops the energy production. The current methods of dealing with this problem are inefficient and pollute the environment. One way with high potential to prevent the build-up of dirt and ice is to use transparent coatings with self-cleaning and icephobic properties. In this work, the chemical modification of an epoxy–silicone hybrid resin using dually functionalized polysiloxanes was carried out. The icephobic properties (ice adhesion and freezing delay time of water droplets), hydrophobic properties (water contact angle, contact angle hysteresis, and roll-off angle), average surface roughness, and optical properties were characterized. It can be concluded that the performed chemical modification resulted in a significant improvement of the icephobic properties of the investigated coatings: ice adhesion decreased by 69%, and the freezing delay time increased by 17 times compared to those of the unmodified sample. The polysiloxanes also caused a significant reduction in the contact angle hysteresis and roll-off angle. The chemical modifications did not negatively affect the optical properties of the coatings, which is a key requirement for photovoltaic applications.

Mode I fracture properties of thermally-modified spruce wood (Picea abies) at different moisture contents

ABSTRACT The influence of moisture content and density on fracture properties of unmodified and thermally modified spruce wood (Picea abies) has been investigated. Thermal modification was done at 180 °C, 200 °C, and 230 °C, and samples were conditioned at 20%, 44%, 76%,% and 88% relative humidity. Double cantilever beam specimens with TL and RL orientation were used for testing. The crack length was determined via digital image correlation, and the compliance of the specimen was determined via multiple loading-unloading cycles of the specimen. The strain energy release rate was calculated, which decreased with an increasing degree of modification and increased with increasing wood moisture content. The analysis showed that the strain energy release rate increased more with wood moisture content for unmodified samples, while the dependence of the release rate on moisture was less obvious for modified samples. The strain energy release rate values are higher in the TL orientation than in the RL orientation, while the crack length has no significant influence. The highest strain energy release rate was 0.256 N/mm for the unmodified TL specimens exposed to 88% relative humidity, and the lowest was 0.071 N/mm for the RL orientation of the thermally modified specimens at 230 °C and then exposed to 88% relative humidity. From all measurements, functions were fitted to calculate the strain energy release rate as a function of orientation, degree of modification, moisture content, and density of the spruce wood, which can be used to calculate the strain energy release rate for any combination of the factors studied.

Contribution of CuO on lamellar BiVO4/Bi2O3-based semiconductor for photoconversion of CO2

Lamellar BiVO4 is a photocatalyst recognized as an effective visible-light-driven semiconductor that is active in CO2 reduction but faces challenges such as high recombination rate and low mobility of photogenerated charge carriers. Additionaly, CuXO are well-known materials for CO2 photosynthesis, and Bi2O3 improves the generation of organic compounds from CO2 reduction with more than one carbon. In this sense, this paper evaluates the influence of small amounts of copper oxide on lamellar BiVO4-Bi2O3 prepared by a microwave-assisted route on the CO2 photoreduction activity. Lamellar BiVO4-Bi2O3 powder catalysts modified by different percentages of CuO were synthesized using microwave heating at 140 °C and 1200 rpm for 15 min. Electrochemical and photochemical characterizations showed that small amounts of copper, such as 1.0%, enhanced the absorption of visible light, improved charge transfer, mitigated charge recombination, and increased the yield of products (acetone and methanol). Furthermore, the flat band potential of the catalyst modified with 1.0% of copper was located at a more negative potential than the unmodified sample, which favored the photocatalytic reduction of the CO2. As a result, the study achieved a 38-fold improvement in methanol generation (1373.5 µmol L−1 gcat−1) and a 62% increase in acetone formation (12.5 µmol L−1 gcat−1) under UV–Vis light incidence over 2 h of reaction at ambient pressure and temperature, compared to pure BiVO4 (36.3 µmol L−1 gcat−1 of methanol and 7.7 µmol L−1 gcat−1 of acetone).

Super-Repellent and Flexible Lubricant-Infused Bacterial Nanocellulose Membranes with Superior Antithrombotic, Antibacterial, and Fatigue Resistance Properties.

Bacterial nanocellulose (BNC) is a naturally derived hydrogel that has recently paved its way in several biomedical applications. Despite its remarkable tissue-like properties, BNC does not express innate anticoagulant or antimicrobial properties; therefore, appropriate post-modification procedures are required to prevent nonspecific adhesion and enhance the hemocompatibility properties of BNC-based biointerface. Here, we report a new class of flexible, lubricant-infused BNC membranes with superior antithrombotic and antibacterial properties. Using chemical vapor deposition, porous BNC membranes were functionalized with fluorosilane molecules and further impregnated with a fluorocarbon-based lubricant. Compared with unmodified BNC membranes and commercially available poly(tetrafluoroethylene) (PTFE) felts, our developed lubricant-infused BNC samples significantly attenuated plasma and blood clot formation, and prevented bacterial migration, adhesion, and biofilm formation and exhibited superior fat and enzyme repellency properties. Moreover, when subjected to mechanical testing, the lubricant-infused BNC membranes demonstrated a significantly higher tensile strength and greater fatigue resistance when compared with unmodified BNC samples and PTFE felts. Overall, the superior mechanical strength and antithrombotic, antibacterial, and fat/enzyme resistant properties observed in the developed super-repellent BNC-based membranes render their application promising for various biofluid-contacting medical implants and tissue engineering constructs.

Green production of plant/collagen-based antibacterial polyvinyl alcohol (PVA) nanocomposite films

The climate crisis, environmental pollution and waste generation have increased the demands for the green production of eco-friendly and bio-based nanocomposites. Modified polyvinyl alcohol (PVA) nanocomposite films were produced using hemp seeds, St. John's Wort, Rosemary and Cherry Laurel plant extracts, collagen and nano silver (AgNPs) and their microstructure, mechanical properties, swelling behavior and antibacterial properties were investigated. Morphological investigations revealed that the PVA matrix was enhanced with green synthesized silver nanoparticles of equiaxed and circular shape in the 30–37 nm size range. It was determined that the produced nature-based nanocomposites hardness are 2.3 times higher than neat un-modified samples, and their swelling in aqueous media was 3.5 times more resistant. Increasing the thermal resistance of green nanocomposite films and creating stronger chemical bonds were achieved by modification of the combined combinations of collagen, plant extracts and nano silver to PVA. In addition, the combination and compositions used in the study made an environmentally friendly nanocomposite films with 10 times stronger antibacterial effects.

Enhancing the Activity of Surface Immobilized Antimicrobial Peptides Using Thiol-Mediated Tethering to Poly(ethylene glycol).

Considering the need for versatile surface coatings that can display multiple bioactive signals and chemistries, the use of more novel surface modification methods is starting to emerge. Thiol-mediated conjugation of biomolecules is shown to be quite advantageous for such purposes due to the reactivity and chemoselectivity of thiol functional groups. Herein, the immobilization of poly(ethylene glycol) (PEG) and antimicrobial peptides (AMPs) to silica colloidal particles based on thiol-mediated conjugation techniques, along with an assessment of the antimicrobial potential of the functionalized particles against Pseudomonas aeruginosa and Staphylococcus aureus is investigated. Immobilization of PEG to thiolated Si particles is performed by either a two-step thiol-ene "photo-click" reaction or a "one-pot" thiol-maleimide type conjugation using terminal acrylate or maleimide functional groups, respectively. It is demonstrated that both immobilization methods result in a significant reduction in the number of viable bacterial cells compared to unmodified samples after the designated incubation periods with the PEG-AMP-modified colloidal suspensions. These findings provide a promising outlook for the fabrication of multifunctional surfaces based upon the tethering of PEG and AMPs to colloidal particles through thiol-mediated biocompatible chemistry, which has potential for use as implant coatings or as antibacterial formulations that can be incorporated into wound dressings to prevent or control bacterial infections.

Preparation of fabric-based electronic device via surface topological modification and enzymatic polymerization for personal thermal management, subtle motion detection, and ultraviolet protection

With the increasingly severe problem of population aging, human motion detection and personal thermal management have attracted widespread attention in the field of smart wearable electronics. However, the current multifunctional flexible devices face problems, such as lower stability and poor comfort, which greatly hinder their further development. In this work, an improved fabrication strategy combining in situ enzymatic polymerization and surface topological modification is proposed to facile and efficiently prepare poly(3,4-ethylenedioxythiophene)/polyacrylamide (PEDOT/PAAm) smart fabric. To increase the conductivity and the bonding force between fabric and PEDOT particles, the PAAm was used to pre-construct a microgel layer on the surface of cotton fabric to make PEDOT uniformly coated on the fabric, thus forming a highly electrically conductive interconnection network. The resulting fabric samples show outstanding duel-driven thermal performance (88.6 °C for 2 sun, 84.5 °C for 10 V), satisfactory detection capability for subtle and rapid motion (drops of water and paper pill, bending of fingers), and remarkable ultraviolet protection performance (24.6 times than the UPF value of unmodified fabric sample). All in all, multifunctional fabric-based devices with remarkable performance exhibited great application potential in rehabilitation therapy and personal home care, especially for people with disabilities and older people.

Effect of thermo-vacuum modification on selected chemical, physical, and mechanical properties of Siberian larch (Larix sibirica L.) wood

ABSTRACT The primary aim of this research was to investigate and evaluate the effects of thermo-vacuum modification through forced convection on selected chemical, physical, and mechanical characteristics of Siberian larch (Larix sibirica L.) wood. Larch wood boards were thermally-modified, using press-vacuum plant technology, for three hours at a temperature of 200 °C and a pressure of 350 mBar. In order to characterise the thermally-modified (TH) and unmodified (CTRL) wood samples, the extractives, lignin and holocellulose content, volumetric swellings, compression strength, and modulus of elasticity (MOE) were determined. Gas chromatographic-mass spectrometric (GC-MS) analysis revealed chemical compound changes as a result of the thermal modification process where some extractives became undetectable after treatment while some new extractives were detected. Thermally-modified larch wood exhibited lower volumetric swelling compared to the untreated samples. Markedly, thermally-modified larch wood had lower tendency to absorb moisture. In addition, thermally-treated wood had slightly higher compression strength parallel to the grain, which was 0.29% higher than that of unmodified samples. Meanwhile, a 7.6% reduction in MOE was recorded in the thermally-treated wood.

Bio‐based compatibiliser enhancing the interface properties of CaCO3/recycled high‐density polyethylene composites

AbstractThe fabrication of composites of two or more materials with different polarities requires the use of compatibilisers to improve interface properties. However, most compatibilisers used for industrial production are derived from the cracking products of petroleum, which is a limited resource susceptible to price fluctuations and pollutes the environment. In this study, a new compatibiliser derived from renewable plant‐oil‐based products, ESO–G–OA, was designed and synthesized using epoxy soybean oil, oleic acid, and glycerol. Scanning electron microscopy results showed that ESO–G–OA can effectively improve the dispersion of CaCO3 in a recycled high‐density polyethylene (reHDPE) matrix and reduce the interfacial gap between the two phases. The analysis of the mechanical properties showed that the ESO–G–OA‐modified composite has higher tensile and impact strength than unmodified samples. The ESO–G–OA modification improved the thermal stability and melt flow of the composite and reduced the energy consumption during processing. Moreover, the excellent compatibility of ESO–G–OA can improve the comprehensive properties of CaCO3/reHDPE composites, compensating for the performance reduction caused by the multiple processing steps necessary to obtain reHDPE. This confirmed that ESO–G–OA has promising application prospects in the production of composites requiring compatibilisers.

Selected Mechanical and Physical Properties of Thermally Modified Wood after Field Exposure Tests

This study aimed to evaluate the impact of thermal modification on the physical and mechanical properties of three different wood species from Bosnia and Herzegovina, namely beech wood (Fagus sylvatica L.), linden wood (Tilia cordata), and silver fir wood (Abies alba). The samples underwent thermal modification at five different temperatures (170 °C, 180 °C, 195 °C, 210 °C, and 220 °C) for varying durations (ranging from 78 to 276 min). After treatment, they were exposed to outdoor conditions for twelve months. The study examined the four-point bending strength, tensile force, color change, and surface quality of the modified and unmodified samples. The results showed that outdoor exposure negatively impacted the mechanical properties of the unmodified samples, especially in the linden wood which was 41% and the beech wood which was 42%. Additionally, outdoor exposure caused significant surface cracks in the thermally modified linden and beech wood. The study also found prominent color changes in the modified and unmodified samples during twelve months of exposure. The roughness of the samples was determined with a confocal laser scanning microscope, which showed that the roughness increased on both the axial and the longitudinal surfaces after weathering. The highest roughness for the fir wood was determined to be 15.6 µm. Overall, this study demonstrates the importance of wood modification and its impact on the use-value of wood products.