Search Results (519)

In an effort to reduce global dependence on fossil-based polymers and advance toward a more sustainable materials industry, research over recent decades has increasingly focused on the development of bio-based polymers and broadening their potential applications. Within this context, the present study investigates nanocomposites based on poly(butylene succinate-co-butylene adipate) (PBSA), reinforced with two types of nanofillers: silicon dioxide nanoparticles (SiO₂ NPs) and cellulose nanofibrils (CNFs). The main objective of this work is to examine how the morphology, geometry, and chemical nature of the nanofillers influence the thermal, mechanical, and barrier properties of PBSA, as well as its biodegradability. For each nanofiller, three formulations were prepared, containing 1, 2, and 5 wt% of filler, respectively. Scanning electron microscopy (SEM) analysis confirmed good dispersion and minimal aggregation in the SiO₂-based systems, whereas marked aggregation was observed in the CNF-based samples. Thermal analysis indicated that the intrinsic thermal properties of neat PBSA were largely preserved. Mechanical testing revealed improvements in both the elastic modulus and elongation at break for most nanocomposite samples. In particular, CNFs provided the most consistent reinforcing effect, with enhancements of approximately 40% in the elastic modulus (495.4 vs. 356.4 GPa in neat PBSA) and 52% in elongation at the break (185.1 vs. 122.0% in neat PBSA) with 5 wt% loading. Additionally, the incorporation of nanofillers did not alter the surface hydrophilicity, but it did improve the oxygen barrier performance and enhanced disintegration under composting conditions. Overall, these findings demonstrate the promising potential of PBSA-based nanocomposites for sustainable rigid packaging applications. Full article

Advanced ceramics are known for their lightweight, high-temperature resistance, corrosion resistance, and biocompatibility. They are crucial in energy conversion, environmental protection, and aerospace fields. This review highlights the recent advancements in ceramic matrix composites, high-entropy ceramics, and polymer-derived ceramics, alongside various fabrication techniques such as three-dimensional printing, advanced sintering, and electric-field-assisted joining. Beyond the fabrication process, we emphasize how different processing methods impact microstructure, transport properties, and performance metrics relevant to catalysis. Additive manufacturing routes, such as direct ink writing, digital light processing, and binder jetting, are discussed and normalized based on factors such as relative density, grain size, pore architecture, and shrinkage. Cold and flash sintering methods are also examined, focusing on grain-boundary chemistry, dopant compatibility, and scalability for catalyst supports. Additionally, polymer-derived ceramics (SiOC, SiCN, SiBCN) are reviewed in terms of their catalytic performance in hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, and CO₂ reduction reaction. CeO₂-ZrO₂ composites are particularly highlighted for their use in environmental catalysis and high-temperature gas sensing. Furthermore, insights on the future industrialization, cross-disciplinary integration, and performance improvements in catalytic applications are provided. Full article

Spent mushroom substrate (SMS)-derived bio-based polyurethane coatings typically exhibit poor hydrophobicity and short nutrient release durations, limiting their ability to satisfy long-term crop requirements. This study developed improved controlled-release urea by preparing water-repellent and compact bio-polymer coatings from recyclable SMS using non-toxic siloxane and nano-SiO₂ modifiers through simple processes. The dual modification markedly reduced water absorption (from 6.60% to 4.43%) and porosity (from 6.32% to 3.92%), creating a dense coating with lotus-leaf-like nanoscale surface protrusions and fewer intermembrane pores. As a result, the nitrogen (N) release period of the dual-modified bio-polymer-polyurethane-coated urea (SBPCU) with a 7% coating thickness was extended from 23 days to 42 days. Phytotoxicity assessments confirmed the excellent biosafety of the bio-polymer coating, revealing no adverse effects on maize growth and even promotional effects at low concentrations. This approach offers a sustainable, eco-friendly, and scalable strategy for producing bio-polymer-coated urea from agricultural waste, serving as a viable alternative to petrochemical coatings while improving nutrient use efficiency and biosafety. Full article

Understanding the role of carrier traps in the determination of dielectric breakdown of polymer nanocomposite would yield a novel method for the estimation of breakdown strength of the material. In this study, we propose a novel approach to predict the DC breakdown strength of polyethylene (PE) and its nanocomposite at room temperature via the bipolar charge transport (BCT) model based on trap energy estimated from isothermal surface potential decay (ISPD). Test specimens of polyethylene (PE) and its nanocomposites, with a thickness of 110 μm, were fabricated using the hot-pressing method by incorporating 20 nm SiO₂ particles as fillers. The distribution of carrier traps within these specimens was subsequently determined through ISPD measurements. The intrinsic breakdown strength of the sample was derived from the determined trap energy levels, by which the breakdown strength was predicted through the BCT model. Experimental DC breakdown tests were conducted on the specimens to validate the accuracy of the predictions. The results indicated that the DC breakdown strength predicted theoretically was in good agreement with that measured from the experiment. Such a prediction method provides a possible way to employ a non-destructive test to evaluate the DC breakdown strength of polymer nanocomposite. Full article

Low-melting bioabsorbable polymers, such as poly(caprolactone-co-lactide) (PCLA), hold significant promise for biomedical applications. However, achieving high-precision micro- and nanotopographical functionalization remains a formidable challenge due to the material’s susceptibility to thermal deformation during conventional thermal molding processes. In this study, functional microstructured PCLA coatings were engineered via low-temperature nanoimprint lithography utilizing a TiO₂–SiO₂ gas-permeable mold. These molds were synthesized via a sol–gel method utilizing titanium dioxide and silicon precursors. The gas-permeable nature of the mold facilitated the efficient evacuation of trapped air and volatiles during the imprinting process, enabling the high-fidelity replication of microstructures (1.3 μm height, 3 μm pitch) and nanostructured PCLA coatings featuring linewidths as narrow as 600 nm. The resultant microstructured PCLA coatings demonstrated modulated surface wettability, evidenced by an increase in water contact angles from 70.1° to 91.4°, and exhibited enhanced FD4 elution kinetics. These results confirm morphology-driven functionalities, specifically hydrophobicity and controlled release capabilities. Collectively, these findings underscore the efficacy of this microfabrication approach for polycaprolactone-based materials and highlight its potential to catalyze the development of high-value-added biomaterials for advanced medical and life science applications. This study establishes a foundational framework for the practical deployment of next-generation bioabsorbable materials and is anticipated to drive innovation in precision medical manufacturing. Full article

Bioactive glasses (BGs) are promising materials for enamel remineralization and caries management due to their ion-releasing ability and capacity to promote apatite formation. However, their clinical translation remains limited. Conventional BGs, such as 45S5, exhibit excellent bioactivity but are mechanically weak, prone to rapid ion burst release, and lack long-term stability. Recent advances—including secondary oxide incorporation (e.g., B₂O₃, ZnO), polymer–glass hybrids, and nanostructured systems like mesoporous BGs and RegeSi have improved reactivity, mechanical performance, and remineralization depth, though their durability under oral conditions is not yet established. BGs also display antibacterial activity by elevating local pH and releasing ions that inhibit cariogenic bacteria, but their broader ecological impact on the oral microbiome remains poorly understood. Emerging approaches such as halogen-modified BGs, particularly fluoride- and chloride-doped formulations, show dual benefits for remineralization and antimicrobial action, though supporting evidence is largely confined to in vitro studies. The absence of standardized protocols for assessing remineralization, ion release, and biofilm interaction further complicates cross-study comparisons and slows clinical adoption. Future progress will require interdisciplinary collaboration, standardized evaluation methods, and rigorous clinical validation to ensure that next-generation BGs can be safely and effectively integrated into dental practice. Full article

This study presents a new ternary copolymer synthesized via aqueous free-radical polymerization from sodium humate, sodium 2-methylprop-2-ene-1-sulfonate (SMAS), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS). The resulting highly water-soluble, three-dimensional porous copolymer is complexed with aluminum sulfate to form a composite admixture containing AlO(OH), which acts as a highly effective accelerator for cement hydration. This system significantly shortens the initial and final setting times to averages of 2.62 min and 4.53 min, respectively, and enhances early-age mechanical strength (1.7 MPa compressive, 1.4 MPa flexural at 6 h). These improvements are correlated with the formation of key crystalline phases, including Al₂Si₂O₅(OH)₄ and Ca₃Al₂O₆·xH₂O gel. Incorporation of 50-mesh carbon fibers further reduces setting times (2.21 min initial, 3.93 min final) and increases 24 h strength (5.2 MPa compressive, 2.7 MPa flexural), despite a slight reduction in early strength (at 6 h). In contrast, 200-mesh carbon fibers extend the initial setting time and diminish early strength, associated with the formation of less effective gel phases such as Ca₃Al₂O₆·xH₂O, (CaO)_x(Al₂O₃)₁₁, and Ca₄Al₂O₇·xH₂O. Among these, the Al₂Si₂O₅(OH)₄ phase demonstrates superior performance, while finer carbon fibers show limited effectiveness in bridging hydration products. Conventionally employed as retarders or reinforcing agents, humate-based polymers and carbon fibers are shown here to function as dual-functional admixtures—serving as efficient setting accelerators while enhancing mechanical properties through tailored material design. This strategy offers a promising pathway for developing advanced multifunctional cement admixtures. Full article

Three new Cu(II) coordination polymers with 4,4′-bipyridine (bpy) were synthesized by hydrothermal reactions and their structures determined by single crystal X-ray diffraction. [Cu(bpy)₃(H₂O)₂](bpy)(PF₆)₂(H₂O)₃ (1) is built from bpy-bridged chains, [Cu(bpy)₂(H₂O)₂](bpy)(PF₆)₂(H₂O)₆ (2) from layers, and in [Cu(bpy)₂(NO₃)](bpy)(PF₆)₂(H₃O)(H₂O) (3) the layers are further connected by nitrate to a cuboid lattice. The magnetic properties of 3 are compared to [Cu(bpy)₂(H₂O)₂](SiF₆) (4) and [Cu(pyz)(bpy)(H₂O)₂](PF₆)₂ (5), where pyz = pyrazine. 3–5 are weakly coupled two-dimensional S = 1/2 antiferromagnetic Heisenberg lattices with 0.86 K < J < 1.47 K. Full article

In this work, novel biomass-derived carbon dots (CDs) with superior fluorescent properties were prepared from tomato straws. A selective, eco-friendly tetracycline (TC) sensor was fabricated by immobilizing a SiO₂ molecularly imprinted polymer (MIP) layer onto CDs, forming a CDs@SiO₂-MIP composite. This sensor combined highly selective adsorption properties with the sensitivity of fluorescence detection, with the sensing mechanism stemming from the off-fluorescent signal after molecular imprinting specifically recognizing the target substance. Under optimal conditions, the sensor exhibited a linear response to TC concentrations ranging from 1.00 × 10⁻⁷ to 5.00 × 10⁻⁴ mol/L, with fluorescence intensity decreasing as concentration increased. The detection limit of TC was 9.33 × 10⁻⁸ mol/L. This work provides novel biomass-derived CDs and a simple molecularly imprinted fluorescence sensing method for the detection of environmental organic pollutants. Full article

The surface modification of coal fly ash (CFA) with silane coupling agents improves its compatibility with polymer matrices and supports its use as a sustainable filler in composite materials. This study examined the effects of the solvent system, reaction temperature, and pH on the grafting of 3-aminopropyltriethoxysilane (APTES) onto CFA surfaces. Functionalization was assessed by Fourier-transform infrared spectroscopy (FTIR), focusing on the CH₂ symmetric and asymmetric stretching bands of pure APTES at 2919 and 2957 cm⁻¹, noting that a slight shift in these bands can be expected following the change in the local chemical environment upon grafting. Solvent mixtures containing water (ethanol/water, acetone/water, and sulfuric acid/water) produced stronger coupling than the toluene solvent, which indicated the importance of water for APTES hydrolysis and silanol formation. Coupling efficiency increased with temperature and reached a maximum at 80 °C, where the balance between hydrolysis and condensation favored the formation of stable Si–O–Si bonds. The highest degree of functionalization was observed at pH 9, which corresponds to the point of zero charge of alumina in CFA, where neutral surface hydroxyl groups were available to react with silanols. These results define the optimal conditions for APTES grafting onto CFA and demonstrate its potential as a silane-modified filler in polymer composites. Atomic force microscopy (AFM) provided direct visual evidence of significant surface texture modifications induced by APTES treatment in the ethanol/water solvent system. Full article

In response to the urgent need for sustainable antibacterial solutions against antibiotic-resistant pathogens, this study presents a facile dendritic polymer-assisted approach for synthesizing highly active ZnO/mesoporous silica nanocomposites (SBA-15, SBA-16, KIT-6, MSU-X). Two hyperbranched polymers—polyethyleneimine (PEI) and carboxy-methylated polyethyleneimine (Trilon-P, TrP)—were employed as templating and metal-trapping agents. The influence of pore geometry, polymer functionality, and polymer-loading method (wet or dry impregnation) on ZnO nanoparticle (NP) formation was systematically examined. All nanocomposites exhibited high structural homogeneity, incorporating ultrasmall or amorphous ZnO NPs (1–10 nm) even at 8 wt.% Zn loading. Zn uptake was strongly dependent on polymer end groups, while the spatial distribution of ZnO NPs was dictated by the silica host structure. Antibacterial assays against Staphylococcus aureus revealed remarkable activity, particularly for ZnO/SBA-15_PEI, ZnO/SBA-16_PEI, and ZnO/MSU-X_TrP nanocomposites, with minimum inhibitory concentrations of 1–2.5 μg mL⁻¹ Zn and over 90% mammalian cell viability. Life Cycle Assessment identified energy use as the main environmental factor, with ZnO/SBA-15_PEI_WI displaying the lowest impact. Overall, the interplay between silica pore architecture, polymer type, and impregnation method governs ZnO accessibility and bioactivity, establishing a versatile strategy for designing next-generation ZnO/SiO₂ nanocomposites with tunable antibacterial efficacy and minimal cytotoxic and environmental footprint. Full article

Red mud, fly ash, ground granulated blast furnace slag, and carbide slag are industrial byproducts posing significant environmental challenges. The synthesis of geopolymers represents a promising approach for their sustainable valorization. This study investigated the strength development mechanisms and microstructural evolution of Red Mud–Class F Fly Ash-Based Geopolymer under co-incorporation of ground granulated blast furnace slag and carbide slag through compressive strength tests, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy–Energy Dispersive Spectrometer (SEM-EDS). Key findings include the following: (1) single incorporation of ground granulated blast furnace slag achieved a 60-day compressive strength of 11.6 MPa—6.4× higher than carbide slag-only systems (1.8 MPa); (2) hybrid systems (50% ground granulated blast furnace slag/50% carbide slag) reached 8.8 MPa, demonstrating a strength peak at balanced ground granulated blast furnace slag/carbide slag ratios; (3) the multi-source geopolymer systems were dominated by monomeric gels (C-A-H, C-S-H, C-A-S-H), crystalline phases (ettringite and hydrocalumite), and poly-aluminosilicate chains ((-Si-O-Al-Si-O-)n); (4) elevated Ca levels (>40 weight percent in ground granulated blast furnace slag/carbide slag) favored C-S-H formation, while optimal Si/Al ratios (1.5–2.5) promoted gel polycondensation into long-chain polymers (e.g., Si-O-Al-O), consolidating the matrix. These results resolve the critical limitation of low strength (≤3.1 MPa) in ambient-cured red mud–fly ash geopolymers reported previously, enabling scalable utilization of red mud (46.44% Fe₂O₃) and carbide slag (92.43% CaO) while advancing circular economy paradigms in construction materials. Full article

This study investigates the mechanical and thermal properties of polypropylene (PP) composites incorporating pumice, a naturally occurring porous volcanic rock with high SiO₂ content, sourced from three regions in Türkiye (Nevşehir, Alaçatı, and Kütahya). Pumice was processed to particle sizes below 10 microns to maximize nucleating effectiveness, and composites were fabricated by melt compounding. The distinct mineralogical composition, porosity, and surface chemistry of the pumice samples enabled systematic evaluation of how regional variations influence crystallization and mechanical performance. A multi-analytical characterization approach, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and standardized mechanical tests (tensile, flexural, and impact), was applied. Results revealed that Alaçatı pumice at 0.1 wt% increased the impact strength of PP by about 11%, while maintaining stiffness. This demonstrates that pumice, unlike conventional fillers, can simultaneously enhance toughness and rigidity. Thermal analysis confirmed improved stability, with higher degradation onset and maximum decomposition temperatures observed in pumice-filled PP. DSC results indicated that certain pumice loadings promoted nucleation and increased crystallinity, while excessive amounts disrupted chain packing. SEM examinations confirmed uniform dispersion at low loadings, with agglomeration at higher levels reducing impact resistance. This work provides the first systematic demonstration of pumice powders as effective nucleating agents in PP, combining regional mineralogical diversity with measurable performance benefits. These findings indicate that pumice can serve as a sustainable, low-cost alternative to conventional nucleating agents, with potential applications in polymer components requiring improved toughness and thermal stability. Full article

This study synthesizes three new composites: chitin-cross-linked poly(ortho-phenylenediamine)-grafted silicon dioxide (CT-PoPD-grafted SiO₂), chitosan-cross-linked PoPD-grafted SiO₂ (CS-PoP-grafted SiO₂), and guar-gum-cross-linked PoPD-grafted SiO₂ (GG-PoPD-grafted SiO₂). These biopolymer-based materials were developed as cost-effective, biocompatible adsorbents with increased surface area for removing Acid Red 1 AR1) and Crystal Violet (CV) dyes. Structural and morphological analyses through Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) confirmed their successful synthesis. Adsorption studies were conducted under various conditions, including adsorbent dosage, pH, temperature, and contact time. Among the composites, GG-PoPD-grafted SiO₂ demonstrated superior performance, achieving 99.1% and 95.6% removal of AR1 and CV, respectively. Kinetic analysis revealed a pseudo-second-order model, while thermodynamic results indicated a spontaneous and endothermic adsorption process. In conclusion, the GG-PoPD-grafted SiO₂ composite exhibits significant potential as an effective and sustainable material for wastewater treatment. Full article

The Na₂O-SrO-SiO₂ system shows promise in the development of glasses that can be transformed into electrically conductive glass ceramics. The conventional processing of such materials usually involves the synthesis of a parent glass, followed by a complex devitrification treatment. This study proposes a simplified approach based on the use of preceramic polymers, namely silicone resins combined with oxide fillers. These systems yield silicate-based ceramics through direct heat treatment, replicating the phase assembly of traditional glass ceramics with no need for prior glass melting. A printable formulation was developed by mixing a silicone resin with an acrylate-based photocurable resin, sodium nitrate and strontium carbonate. The resulting ‘suspension-emulsion’ was later shaped into monolithic components using digital light processing. After pyrolysis in nitrogen atmosphere, the components transformed into SrSiO₃ crystals embedded in a composite matrix, in turn composed of glass and turbostratic carbon (the latter specifically offered by the silicone polymer). This combination of crystalline silicates and carbon resulted in measurable electrical conductivity. This study confirms that silicone-derived systems can serve as effective precursors for conductive glass-ceramic analogues, providing an alternative to conventional methods with single-step processing. This approach enables structural shaping through 3D printing and the development of functional properties suitable for electronic or electrochemical applications. Full article