The growing demand for sustainable lightweight materials has encouraged the development of hybrid polymer composites reinforced with natural fibers and agricultural waste. In this study, polypropylene (PP) hybrid composites reinforced with short woven hemp fibers (SWHFs), chopped basalt fibers (BFs), wheat straw ash (WSA), and maleic anhydride-grafted PP (MAPP) were developed and systematically investigated. The experimental program was conducted in two stages. First, the BF content was optimized by incorporating 5–25 wt.% BF into PP containing 25 wt.% SWHF. The optimized formulation was then modified by adding 6, 12, and 18 wt.% WSA with a constant MAPP content. The composites were fabricated by twin-screw extrusion followed by injection molding and characterized using tensile and flexural tests, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Incorporation of 20 wt.% BF increased the tensile strength and modulus of the hemp fiber-reinforced PP composite by approximately 21% and 94% (from 35.62 to 43.00 MPa and 1.80–3.50 GPa, respectively), together with 30% and 50% increases in flexural strength and modulus (56.48–73.28 MPa and 2.42–3.62 GPa). Incorporation of WSA further increased tensile and flexural modulus by up to 41% and 55% relative to the BF-optimized composite, while MAPP addition raised tensile strength by up to 27% (43.00–54.50 MPa), consistent with improved matrix-reinforcement compatibility. SEM revealed fewer visible interfacial voids in the examined regions of the MAPP-containing composites, and FTIR revealed spectral changes consistent with modified interfacial interactions between the constituents without direct evidence of new covalent-bond formation. TGA showed that the residual char yield increased from 0.20% for neat PP to 13.83% after BF incorporation and up to 16.0% for the WSA/MAPP-modified composites, indicating an increased thermally stable residual fraction. Among the WSA-modified formulations, the 6 wt.% WSA composite exhibited the highest tensile and flexural strength (54.50 and 86.40 MPa, respectively), whereas the 12 wt.% WSA composite provided marginally higher tensile and flexural moduli (4.94 and 5.62 GPa) together with a more balanced thermal response; the latter (25SWHF/20BF/PP-6MAPP-12WSA) is therefore identified as the formulation offering the best overall property balance rather than the single highest-strength composition. These findings demonstrate the potential of WSA as a sustainable inorganic functional filler for high-performance PP hybrid composites.

This paper explores mechanical behaviour and moisture absorption of Banana fibre-reinforced epoxy composite prepared by the vacuum bag moulding process. The composite laminates were made with different weight fractions of Banana fibres viz., 10%, 15%, 20%, 25% and 30%. The systematically measured key mechanical properties, including tensile, flexural, impact resistance, surface hardness, and the water absorption properties were tabulated and compared. Findings revealed a steady increase in mechanical performance as the fibre content increased up to 25 wt.% Specimen S25 with the highest tensile strength 178 MPa, flexural strength 245 MPa, impact resistance 4.2 kJ m−2, and hardness 78 Shore D being observed for S25 specimen. A drop in performance after this point was ascribed to fibre agglomeration, poor wetting of the resin and formation of voids. Moisture uptake was highest for 30 wt.% composite (Specimen S30) mainly because of high porosity and loose interfacial bonding. The experiment determines that 25 wt.% Banana fibre is the best reinforcement content that gives an equilibrium between mechanical integrity and water resistance. The research results highlight the possibility of Banana fibre-reinforced epoxy composites as sustainable, lightweight and high-performing materials to be used in automotive interiors, construction, furniture, and packaging.

In this study, polyester and vinyl ester resins were used as matrix materials, while pine root, cotton waste, and corn stalk waste were selected as reinforcement materials. The effects of combining these wastes at different reinforcement ratios on the thermal and mechanical performance of the composite samples were investigated. Composite test specimens were produced using the open molding method with agricultural waste reinforcement at 2.5%, 5%, and 10% by weight. Hardness and tensile tests were applied to determine the mechanical properties of the obtained specimens, while thermal conductivity measurements were performed to determine their thermal behavior. The findings showed that the vinyl ester matrix composite specimen with 2.5% corn stalk waste filling exhibited the highest tensile strength, while the polyester matrix composite specimen with 10% cotton stalk waste filling showed the lowest strength. Similarly, the polyester matrix composite specimen with 2.5% cotton stalk waste filling had the highest hardness value in the hardness tests, while the polyester matrix composite specimen with 10% pine root waste filling had the lowest value. In thermal conductivity tests, the highest thermal conductivity value was measured in the vinyl ester matrix composite sample filled with 2.5% corn waste, while the lowest value was measured in the polyester matrix composite sample filled with 2.5% pine root waste. In conclusion, it has been shown that environmentally friendly and sustainable composite materials can be obtained by integrating agricultural wastes into polymer matrix composites, and that this will provide an innovative and alternative contribution to fields such as automotive, insulation, and construction applications.

The pyrolysis of coconut husk (CH) impregnated with Mg(OH)2 at 400 °C produced MgO nanoparticles/coconut husk biochar (MgO NPs/CHB) containing 1.29% MgO (w/w). The biochar yield from Mg(OH)2-treated biomass reached 51.47%, which was higher than that obtained from untreated CH (41.23%). The morphology and particle size of MgO NPs were characterized by scanning and transmission electron microscopy, with average sizes of about 24.4 nm and 28.4 nm, respectively. The structural and physicochemical properties of the material were analyzed using x-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and N2 adsorption-desorption analysis. Seed priming with MgO NPs/CHB at a concentration of 100 mg MgO/L improved the ability of rice seedlings to cope with salt-induced stress, as indicated by increased chlorophyll content, plant height, and root length after 7 days of salt treatment under 75 mM NaCl. In addition, MgO NPs/CHB priming alleviated salt-induced stress in rice seedlings, as evidenced by reduced activities of antioxidant enzymes compared to the salt-stressed control, such as superoxide dismutase and catalase, lower malondialdehyde content, and an increased K+/Na+ ratio in leaves compared to the non-primed salt-stressed control.

This study presents a comprehensive system for the high-temperature microwave characterisation of dielectric materials. This system addresses the current scarcity of reliable dielectric data above 1000 °C, particularly under concentrated solar irradiation. A solar simulator comprising seven xenon arc lamps delivers highly focused energy, enabling rapid temperature ramp rates and temperatures in excess of 1000 °C. Small samples are heated directly within the resonator via solar heating, and the permittivity and loss tangent are extracted in the S-band (2–4 GHz) using a specially adapted re-entrant cylindrical cavity. The cavity is produced using additive manufacturing, is internally gold-plated, and incorporates an integrated cooling system to ensure operational stability under extreme thermal loads. A multiphysics algorithm based on COMSOL simulates the coupled thermal and electromagnetic behaviours, accounting for the effects of cavity expansion and temperature-dependent conductivity that are often neglected in high-temperature measurements. Experimental results obtained with alumina samples demonstrate good agreement between simulations and measurements, showing an increase in effective permittivity with temperature. These results highlight the potential of the proposed platform for accurately characterising dielectrics in extreme environments. However, further refinement is required for the precise estimation of the loss tangent and associated uncertainties.

The growing amount of biomedical waste (BMW) and its byproduct ash (BMWA) obtained during BMW incineration creates considerable issues regarding environment pollution and risks associated with unregulated disposal, emissions into the air, and potential release of contaminants into the soil. This review article critically assesses the prospects of BMWA reuse as an additional component or alternative material to be used alongside common construction materials in cements. The study summarises the information on BMW production and management, BMWA physicochemical and mineralogical properties, treatment and stabilisation techniques, and the impact of BMWA inclusion on fresh state, mechanical properties, microstructure, and durability of concrete and similar building materials. Specific focus is placed on heavy metals immobilisation, leaching potential, environmental safety and adherence to existing standards. Furthermore, bibliometric analysis is carried out in order to trace scientific trends and gaps in knowledge. The results suggest that regulated BMWA inclusion at approximate levels of 5%–10% replacement could help to achieve similar or improved properties of construction materials and to minimise waste disposal and resource usage.

Ni–Co alloy and composite coatings are of high industrial importance due to their high corrosion resistance and mechanical properties. The properties of the Ni–Co coatings can be further increased by incorporating reinforcing particles into the alloy matrix. The corrosion resistance, hardness, and wear resistance of the Ni–Co coatings can be significantly increased by the addition of various reinforcing particles in the form of nanoparticles. In this article, various methods for the deposition of Ni–Co composite coatings will be discussed, followed by a brief discussion on the improvement in corrosion resistance, hardness, and wear resistance caused by the addition of such particles.

Asphalt mixtures must meet both mechanical and thermal requirements, but, these two response classifications are rarely evaluated within a single compositional framework. In this work a controlled full factorial matrix was tested, where two types of aggregates (basalt and limestone), two bitumen penetration grades (50/70 and 70/100) and two binder conditions (reference and 10% Gilsonite-modified) were mixed at a fixed binder content of 5.0%. Three independent specimens per mixture were used for the determination of Marshall stability, flow and MQ, and the analysis was performed by three-way ANOVA. The thermal-conductivity findings, obtained as repeated needle-probe readings on a single specimen per condition, are described descriptively. The Marshall stability of all the mixes was improved by 5.6%–28.0% with Gilsonite modification. Flow was controlled by a significant aggregate × binder grade interaction while the MQ had a significant aggregate main effect and an aggregate dependent response to binder grade. The basalt mixtures exhibited higher Marshall stability and thermal conductivities, 32%–40% higher than those of the corresponding limestone mixtures. Factorial variance decomposition represented 83.3% of the conductivity variance by aggregate type and Gilsonite modification increased the mean conductivity by 2.3%–8.5%. The results were in agreement with the three-phase effective-medium back-calculation, which showed that the aggregate phase was primarily responsible for the conductivity of the combination. Marshall stability and thermal conductivity were highly associated for the entire data set, but this connection was significantly diminished when controlling for aggregate type, indicating an aggregate-mediated relationship rather than a mechanical-to-thermal causation. The traditional binder tests and the Fourier-transform infrared spectra suggest a binder-stiffening process for the mechanical improvement but do not explain the thermal changes by themselves. Overall, the aggregate type was the dominant factor controlling the coupled mechanical-thermal behaviour, with the binder grade and Gilsonite modification being secondary system-dependent variables.

Recycled polyethylene (r‐PE) is a promising recycled polymer modifier for asphalt, yet its inherent non‐polar property leads to poor interfacial compatibility with asphalt matrix, triggering phase separation, particle agglomeration and degraded low‐temperature cracking resistance. In this work, waste high‐density polyethylene plastic bottles were adopted as raw material, and two functionalized r‐PE modifiers bearing ester (–COOR) and carboxyl (–COOH) groups were synthesized through melt‐grafting. Modified asphalt specimens with modifier dosages ranging from 1% to 5% were prepared by high‐speed shearing with 70# base asphalt. Conventional performance tests, storage stability evaluation, dynamic shear rheometer tests, Fourier transform infrared (FTIR) and SEM micro‐characterization were carried out. Combined with matrix‐based multiple regression and quantum‐chemical molecular simulation, this study quantitatively separated the weighting effects of functional‐group type and modifier dosage, and comparatively revealed the interfacial modification mechanisms. The results demonstrate that functionalization significantly enhances the interfacial interaction between r‐PE and asphalt, and r‐PE‐COOH achieves better overall performance. At the optimal dosage of 3% (under the experimental conditions of this study), r‐PE‐COOH‐modified asphalt has a 5 °C ductility of 32.0 cm, which is 18.5% higher than r‐PE‐COOR modified asphalt and 47.5% higher than unfunctionalized r‐PE modified asphalt. Within the dosage range of 1%–5%, r‐PE‐COOH‐modified asphalt maintains a softening‐point difference below 2.1 °C and exhibits superior rutting resistance according to rheological tests. Regression analysis identifies modifier dosage as the dominant factor governing rheological properties, whereas functional‐group type exerts a secondary influence. Microscopic and simulation results indicate that r‐PE‐COOH forms stable cross‐linked networks via esterification reaction with polar components in asphalt, while r‐PE‐COOR mainly interacts through physical adsorption. Both modifiers construct the dual ‘cross‐linked network‐particle anchoring’ structure to improve compatibility. This study provides theoretical support for the molecular design of sustainable recycled‐polymer asphalt modifiers.