Search Results (286)

Mixed-matrix membranes (MMMs) incorporating porous organic fillers into high-performance polyimides were developed to investigate the influence of free volume and molecular architecture on gas transport. Four structurally rigid, intrinsically porous fillers (TFAP-Trp, Is-Trp, TFAP-TPB, and Is-TPB) were incorporated into a range of polymer matrices (P84^®, Matrimid^®, Pi-DAPOH, Pi-DAROH, Pi-HABAc, Pi-DAM, and PIM-1), enabling the development of a matrix-independent methodology for estimating intrinsic filler permeabilities for five gases (He, O₂, N₂, CH₄, and CO₂). This comprehensive multi-matrix, multi-gas study reveals a strong correlation between filler fractional free volume (FFV), BET surface area, and gas permeability, with isatin-based fillers exhibiting particularly high CO₂ permeability. Filler incorporation generally resulted in substantial permeability enhancements (100–350%) while maintaining selectivity, often with only minor losses or even favorable improvements in CO₂/CH₄ and He/CH₄ separation performance. Several MMMs, particularly those based on Pi-DAPOH and Pi-DAROH polyimides, approached or exceeded the Robeson upper bound. Analysis of permeability as a function of gas kinetic diameter further elucidated clear structure–property relationships, confirming that filler-induced disruption of polymer chain packing and the creation of additional transport pathways are the primary factors governing separation performance. Overall, these findings demonstrate that rationally designed porous organic fillers provide a robust and broadly applicable strategy for mitigating the permeability–selectivity trade-off in polymer membranes and enhancing gas separation efficiency. Full article

To develop high-performance and eco-friendly passive daytime radiative cooling (PDRC) materials, calcium carbonate (CaCO₃)/porous polylactic acid (PLA) nanofibers were fabricated via electrospinning. This fabrication utilized PLA as the matrix and 40 nm CaCO₃ nanoparticles as fillers, with ambient humidity controlled above 85%RH during electrospinning. The resulting nanofibers possessed numerous CaCO₃/PLA interfaces and porous surface structures. Experimental results demonstrated that the CaCO₃/porous PLA nanofibers achieved a solar reflectivity of ~92.3%, significantly exceeding that of PLA (~72.1%), CaCO₃/PLA (~86.0%), and porous PLA (~79.6%) nanofibers. During outdoor testing, CaCO₃/porous PLA nanofibers exhibited optimal PDRC performance with a temperature reduction of ~10.3 °C, representing a 6.1 °C improvement compared to PLA nanofibers. This enhancement is attributed to synergistic light-scattering sites generated by surface porosity and CaCO₃/PLA interfaces, which collectively strengthen solar spectrum scattering. Furthermore, significant morphological degradation was observed after 80-day soil burial, confirming biodegradability. This study proposes a facile strategy for developing high-performance eco-friendly PDRC materials. Full article

The transition toward circular economy practices and CO₂ reduction goals is driving the development of new sound absorption technologies. Traditional absorbers made from mineral wool or foams provide broadband absorption; however, their production is associated with intensive energy consumption and non-renewable resources. This is why the focus has been shifting from the mere substitution of materials to integrated solutions that combine sustainability with structure. This paper reviews recent innovations in sustainable absorbers based on bio-based and recycled materials. The acoustic performance of porous materials depends on such factors such as pore structure, airflow resistivity and geometric parameters such as thickness, multi-layer structure and resonances. At the same time, additive manufacturing (AM) allows creating geometry-controlled absorbers providing advanced acoustic properties. Despite many sustainable absorbers demonstrating sufficient sound absorption properties at medium and high frequencies, their use at low frequencies remains challenging. Additionally, concerns regarding durability, flame retardance, and environmental consistency continue to limit their broader application. Yet, hybrid, multi-material strategies, particularly those combining geopolymer matrices with bio-based or recycled fillers, are identified as a promising route to address these limitations. This review outlines current trends and highlights key challenges and future directions in the design of sustainable sound-absorbing systems. Full article

Polyhydroxyalkanoates (PHAs) are bio-based, biodegradable polyesters increasingly explored as sustainable biomaterials for regenerative medicine. This review summarizes recent advances in PHA-based bone substitute materials, highlighting their properties, fabrication methods, and biological performance. PHAs combine biocompatibility, tunable mechanical behavior, and degradation into non-toxic metabolites, while copolymerization and monomer selection modulate the stiffness, crystallinity, and resorption rate. Processing techniques such as solvent casting, electrospinning, and additive manufacturing allow the production of porous architectures that mimic bone extracellular matrix. Electrospinning is particularly suitable for nanoscale fibrous matrices, whereas 3D printing enables patient-specific scaffolds with controlled geometry and interconnected porosity. Scaffold performance can be further improved through the incorporation of osteoconductive fillers, including hydroxyapatite, β-tricalcium phosphate, bioactive glasses, graphene oxide, and carbon nanotubes, as well as through drug-delivery and pro-angiogenic functionalization. In vitro and in vivo studies consistently report favorable cytocompatibility, enhanced osteogenic differentiation, vascularization, and effective repair of bone defects in animal models. However, clinical translation remains limited by production costs, variability in polymer quality, thermal processing constraints, and regulatory challenges. Future progress will rely on more efficient biosynthesis, medical-grade purification, multifunctional scaffold design, and stronger collaboration between academia, industry, and clinicians to unlock the full potential of PHAs in regenerative bone therapies. Full article

Conductive hydrogel strain sensors using poly(3,4-ethylenedioxythiophene) (PEDOT) as fillers are rapidly advancing and are emerging as candidates for monitoring devices such as wearable electronic skin. However, due to limitations such as low elongation and high hysteresis, it is difficult to fully leverage its promising sensor properties in practical applications. In this study, we synthesized flake-like PEDOT particles (FP particles) and used Polyacrylamide (PAM) as the hydrogel matrix to fabricate a conductive hydrogel strain sensor. These particles were obtained by grinding PEDOT particles prepared via a template-free method. After swelling with ethylene glycol (EG) and assembly with polyvinyl alcohol (PVA), the FP particles become porous and contain many hydroxyl groups. This design enables the adsorption of acrylamide (AM) monomers within FP particles, facilitating the in situ polymerization of PAM onto the PEDOT/PVA chains, thereby yielding a dual-network structure with strong entanglements. This gives the sensor high elongation and very low hysteresis. In addition, it offers favorable sensor performance, including high sensitivity, high repeatability, and reliability. This strain sensor can be used in wearable electronic skin applications for facial monitoring and motion detection. Full article

Carbon/inorganic hybrid composites have evolved from filler-reinforced materials into design platforms for coupled electromagnetic, thermal, sensing, environmental, protective and energy-related functions. Their distinctive value lies in the possibility of combining a conductive, polarizable or porous carbon phase with an inorganic phase that contributes dielectric, magnetic, catalytic, ionic, thermally conductive or barrier behavior. This review examines carbon/inorganic hybrid multifunctional composites from the viewpoint of structure–property relationships, with emphasis on interfacial design, percolation, anisotropy, hierarchical architecture, processing and metrology. Selected graphitic composite studies are discussed as case studies for broadband dielectric spectroscopy, microwave shielding, high-frequency contact metrology, thermal diffusivity analysis and impedance-monitored graphene filters; these case studies are integrated with the broader international literature on CNT and graphene polymer composites, MXene films and foams, graphene/metal oxide photocatalysts, boron nitride/carbon thermal networks, biochar–graphene adsorbents, smart coatings, sensors, supercapacitors and water remediation systems. The central argument is that credible multifunctionality requires more than measuring several properties on the same material. It requires simultaneous or service-relevant co-optimization under constraints of thickness, density, processability, aging, humidity, corrosive media, regeneration, toxicity, economic feasibility and scalable fabrication. The review concludes with design rules and reporting recommendations intended to help move the field from impressive property demonstrations toward application-ready hybrid material systems. Full article

The present study addresses the fabrication of porous gyroid architectures by additive manufacturing from preceramic polymer feedstocks. Photocurable emulsions were engineered by combining a silicone powder with acrylate monomers and dispersing an emulsified secondary phase of calcium nitrate. The formulations showed light-curing behaviour compatible with digital light processing vat photopolymerization (DLP-VPP), enabling high-fidelity replication of triply periodic minimal surface (TPMS) gyroids (designed porosity: 85 vol.%). After pyrolysis in nitrogen at 700 °C, the lattices converted into CaO–SiO₂-derived amorphous matrices embedding an in situ turbostratic/pyrolytic carbon fraction, as suggested by the photothermal response and preliminary impedance behaviour, although the latter was measured in liquid electrolyte and therefore does not isolate electronic transport. To improve robustness during polymer-to-ceramic conversion, pharmaceutical borosilicate waste glass (BASG) was added as a passive filler (30–70 wt.%). The waste-glass phase acts as a passive filler that improves processing robustness and can mitigate shrinkage-induced damage during pyrolysis, while remaining electrically insulating (dielectric) and therefore not directly contributing to electronic conduction. The resulting structures combine high surface-to-volume ratio, controlled open porosity, and structural integrity with electrochemical responsiveness under the adopted test conditions, making them promising architected platforms for electrochemical components where interconnected porosity is advantageous. Full article

To address the severe wear and galvanic corrosion of TC4/Mg three-dimensional interpenetrating composites caused by the potential difference and hardness disparity between the two phases, this work proposes a hybrid surface modification strategy combining plasma electrolytic oxidation (PEO) with a self-assembled monolayer (SAM) doped with multi-walled carbon nanotubes (MWCNTs). A PEO ceramic coating was first grown in situ on the composite surface, followed by sealing modification using MWCNTs-containing SAM. The microstructure, phase composition, tribological behavior and potentiodynamic polarization curves of the coatings were systematically evaluated. The results show that the PEO coating is mainly composed of Mg₂SiO₄, MgO, MgF₂ and TiO₂, exhibiting a typical porous structure. After the MWCNTs-doped SAM composite modification, the nano-fillers and the molecular layer synergistically seal the micropores and cracks, and the surface transforms into a continuous and dense layered morphology. Wear tests reveal that the composite coating reduces the friction coefficient to 0.195 and decreases the wear volume by 93.53% compared with the bare composite. The “micro-roller bearing” effect and debris adsorption of MWCNTs significantly improve the wear resistance, and the dominant wear mechanism changes from abrasive wear to three-body wear. Electrochemical measurements show that the corrosion current density of the composite coating decreases from 2 × 10⁻⁴ A·cm⁻² (bare composite) to 1.401 × 10⁻⁹ A·cm⁻², i.e., a reduction by five orders of magnitude, with a protection efficiency of 99.99%. This is attributed to the physical barrier effect of the PEO coating and the synergistic sealing of defects, as well as the blocking of electron transfer by MWCNTs/SAM. The multi-level protection system of “PEO + MWCNTs + SAM” constructed in this work achieves a synergistic improvement in both wear resistance and corrosion resistance of the TC4/Mg two-phase interpenetrating composite, and holds promise for further investigation as an osseointegration implant material. Full article

High-performance polyethersulfone (PES) ultrafiltration membranes integrating antibacterial activity and antifouling performance were fabricated via the in situ construction of bimetallic polyphenol networks (BMPNs) throughout the membrane architecture. Tannic acid (TA) functioned as a multifunctional molecular bridge, functionalizing silver metal–organic frameworks (Ag-MOFs) to yield hydrophilic T-Ag-MOFs and chelating Fe³⁺ ions from the coagulation bath to form a polyphenol network during phase inversion. T-Ag-MOF incorporation generated asymmetric morphologies featuring highly porous surfaces and sponge-like cross-sections, improving pure water permeability, mechanical integrity, and bovine serum albumin (BSA) rejection. TA-mediated functionalization increased hydrophilicity, imparted a negative surface charge, suppressed nonspecific protein adhesion, and enhanced flux recovery with low irreversible fouling. At an optimal loading of 0.4 wt%, the resultant T-Ag-MOF/Fe³⁺/PES composite membrane achieved a pure water permeability of 593.4 L m⁻² h⁻¹ bar⁻¹—1.77-fold higher than that of the pristine PES control—while sustaining a BSA rejection of 96.5%. Notably, interfacial compatibility between the T-Ag-MOFs and PES matrix was enhanced, facilitating strong, covalent-like filler–matrix adhesion. Moreover, the composite membrane delivered synergistic multifunctionality, including exceptional long-term aqueous stability, precisely tuned Ag⁺ release kinetics, and potent antibacterial activity, as evidenced by negligible uncontrolled ion leaching and a lack of structural degradation under prolonged hydration. Full article

This comprehensive review aims to cover the surface tribology and triboelectric properties of additively manufactured (AM) natural biopolymers, including cellulose, chitosan (CS) and silk fibroin (SF), in biomedical interface engineering. While these sustainable materials exhibit innate biocompatibility and tribopositivity, their baseline triboelectric performance demands targeted surface engineering. We synthesize key physical mechanisms governing charge generation, emphasizing how controlled surface roughness, hierarchical porosity and nanoscale architectures maximize contact electrification. Furthermore, distinct dielectric and polarity modulation strategies are evaluated across the biopolymer families: cellulose relies heavily on chemical functionalization to overcome weak native polarity; chitosan utilizes ionic coordination and fillers to elevate its relatively low charge density; and silk fibroin achieves exceptional power outputs via highly porous three-dimensional nanocomposite aerogels. AM technologies afford unprecedented spatial control over these biointerfaces but introduce severe processing constraints. Techniques such as those based on extrusion impose strict shear-thinning rheology and rapid crosslinking for cellulose and chitosan, while SF frequently suffers from crystallization-induced nozzle clogging, necessitating photocurable derivatives. Full article

The article is devoted to the study of the properties of the obtained heat-insulating refractory materials, based on fireclay scrap of various fractions (2.5 mm, 1.0 mm, 0.5 mm, and 0.1 mm) using a complex of mineral and oxide additives. The fillers used were titanium dioxide powder and silicon production wastes, which included microsilica powder, aluminum oxide, zinc oxide, zirconium oxide, chromium oxide, iron oxide, cement, lime, and baking soda. The choice of these fillers was due to the fact that they initially have corrosion resistance. Liquid glass acted as a binder. The resulting thermal barrier material was tested to determine its physical and mechanical properties, namely, thermal conductivity, porosity, compressive strength, and microstructure. According to the obtained results for the physical and mechanical properties, the secondary refractory material had properties close to GOST. So, according to GOST 12170-2021, the thermal conductivity values of the obtained materials were included in the 0.03–15.0 W/(m·K) range. The porosity values of the obtained samples complied with GOST 2409-2014 and were not more than 30%. The maximum compressive strength was 171.31 kgf/mm². The microstructure of the material of the obtained samples was very porous, and the pores were evenly distributed throughout the volume, which is extremely important for heat-insulating materials. A distinctive feature of the technology was the absence of a high-temperature firing stage: the required physical and mechanical properties of the material were achieved when heated to 180–300 °C with subsequent slow cooling in the furnace, which significantly reduces energy consumption compared to traditional refractory technologies. The use of waste from the production of chamotte scrap and microsilica will help to reduce negative impacts on the environment, save natural resources, and expand the raw material base. Full article

This study presents the development of biocompatible antistatic nanofibrous composite yarns via a scalable AC electrospinning method, incorporating ultrasonicated expanded graphite (uEG) and PEDOT:PSS into polyamide (PA), polyvinyl butyral (PVB), and polyvinyl alcohol (PVA) matrices. TGA confirmed high filler retention during electrospinning. Electrical measurements showed that the addition of uEG and micrographite reduced single-yarn resistance by up to two orders of magnitude compared with neat polymers, yielding normalised resistivities as low as ~10⁵–10⁶ Ω·m and conductivities in the 10⁻⁷–10⁻⁵ S/m range, suitable for antistatic and sensing applications. However, the large filler–fibre size mismatch and highly porous yarn architecture limited the formation of continuous conductive networks, and mechanical tests revealed strength reductions of up to 70–80% at the highest PVB filler loadings. XRD confirmed a reduction in crystallinity with filler addition, PEDOT:PSS enhanced polymer chain nucleation and thus mechanical properties. Cytotoxicity assays demonstrated that uEG, micrographite, and PEDOT:PSS significantly improved cell viability compared with non-crosslinked PVA, with several PVB-based and PVA/uEG composites showing viability statistically comparable to the DMEM control (>70%) while remaining significantly higher than the Triton positive control. Overall, this work establishes an AC-electrospun route to antistatic nanofibrous yarns that combine high filler retention with enhanced biocompatibility. Full article

The complete removal of persistent aromatic organic pollutants from aqueous environments demands the development of sustainable and highly efficient filtration materials. In this study, novel bio-sourced mixed-matrix membranes (MMMs) were successfully fabricated by incorporating the highly porous metal–organic framework MIL-68(Al) into a biodegradable polylactic acid (PLA) matrix via a solvent-induced phase inversion method. The integration of MIL-68(Al) nanoparticles significantly tailored the membrane’s morphological structure, endowing the hybrid membranes with enhanced surface hydrophilicity (water contact angle reduced from 90.3° to 72.7°) and superior permeability. The pure water flux reached an optimal value of 42.2 L m⁻² h⁻¹ at a 15 wt.% MOF loading. Crucially, the hybrid membranes exhibited exceptionally high adsorptive removal performance for p-nitrophenol (PNP) and methylene blue (MB). Driven by the abundant accessible active sites of the MOF filler, the MIL-20/PLA membrane achieved a maximum equilibrium adsorption capacity of 121.03 μg/cm² (36.90 mg/g) for PNP, representing a remarkable 25.7-fold enhancement over the pristine PLA membrane. Kinetic analyses confirmed that the adsorption process is strictly governed by pseudo-second-order kinetics, indicating a chemisorption mechanism dominated by hydrogen bonding and π–π stacking interactions. Furthermore, the optimized membranes demonstrated outstanding dynamic filtration efficiencies (>80%) and robust regenerability over multiple continuous operating cycles. This work not only highlights the synergistic interfacial effects between MOFs and biodegradable polymers but also provides a highly effective, eco-friendly, and sustainable membrane platform for the advanced remediation of organic-contaminated wastewater. Full article

The rapid development of tropical island tourism has put forward a higher demand for asphalt pavement construction on the island. However, the asphalt pavement engineering in the offshore area is generally faced with high material transportation costs. Additionally, challenges such as high-temperature climate and heavy-load traffic may lead to permanent pavement deformation. As a typical marine solid waste, shells have high calcium carbonate content and porous structures, which have the potential advantage of modified asphalt. In this study, mixed shell powder was used as a modified material, and 70 # base asphalt and SBS-modified asphalt were mixed, respectively. The effect of asphalt modification was analyzed by basic performance tests and high-temperature rheological tests. An asphalt mixture was prepared by replacing limestone powder with mixed shell powder in equal volume, and its road performance was systematically tested. The modification mechanism was revealed by means of a microscopic test. The results show that the recommended content of mixed shell powder in SBS-modified asphalt is 9%, and 50–100% mixed shell powder can be used to replace mineral filler in base asphalt and single SBS modified asphalt mixture. This study provides effective technical support for the utilization of shell solid waste in offshore areas and the optimization of asphalt pavement performance. Full article

This study investigated the electrical insulation properties of epoxy matrix composites reinforced with carbonized palm kernel shell (PKS) particles. The raw PKS particles were collected, sun-dried, and further oven-dried at 105 °C for 2 h to eliminate residual moisture. The dried shells were then carbonized in an airtight furnace at three different temperatures: 450, 550, and 650 °C. After carbonization, the material was crushed and sieved into particle sizes of 200, 400, and 800 µm using an electromagnetic sieve shaker. Composites were fabricated by incorporating carbonized PKS particles into an epoxy resin matrix at varying weight fractions of 30, 40, 50, and 60 wt%. Electrical insulation performance was evaluated at room temperature and pressure using high-voltage DC test equipment for dielectric strength and a digital insulation tester (MIT 520/2) for resistivity measurements. The results revealed that optimal dielectric strength and resistivity were achieved with smaller particle sizes, lower filler loadings, and at low temperatures. Mineralogical characterization via X-ray diffraction confirmed that there was no radioactive element. Scanning Electron Microscopy revealed porous microstructures within the carbonized particles. Energy-dispersive X-ray spectroscopy indicated that carbon accounted for the highest elemental composition, followed by oxygen. It is concluded that PKS-reinforced epoxy composites exhibit promising electrical insulation properties. Full article