Search Results (978)

Background: Oromucosal films are thin polymeric dosage forms designed to hydrate rapidly in the oral cavity and enable local or systemic drug delivery. Their performance depends on coupled processes including wetting, swelling, polymer relaxation, matrix softening, and structural failure. Because these phenomena depend strongly on the formulation composition and polymer-network organization, a mechanistic framework linking conventional characterization data to film performance is needed. This study aimed to develop a Madelung-type multifractal swelling–disintegration–release-readiness model for chitosan/hydroxypropyl methylcellulose (HPMC) films and to examine its relevance using a twelve-formulation experimental series. Methods: Twelve films based on chitosan (film-forming polysaccharide), HPMC K-4M (hydrophilic swelling polymer), glycerin (plasticizer), and starch (disintegrant) were prepared via solvent casting. The films were characterized for loss on drying, surface pH, mass and thickness uniformity, wetting time, swelling behavior, structural-disintegration onset, elongation response, rupture resistance, folding endurance, and surface roughness. The proposed model described water uptake, swelling-front motion, matrix integrity, local release-readiness activation, and hydration-induced loading as coupled fields across the film thickness. Results: Formulation markedly influenced hydration behavior, mechanical performance, structural stability, and surface morphology. Films F2 and F7 emerged as the most promising complementary unloaded matrix platforms for future active-compound incorporation and experimental release evaluation. F2 behaved as a high-swelling, mechanically stable starch-free matrix, whereas F7 combined faster wetting, starch-assisted structural destabilization, and favorable flexibility. Conclusions: This framework provides a quantitative link between empirical film characterization and formulation-level mechanistic interpretation. It translates conventional characterization parameters into descriptors related to the apparent water penetration, swelling capacity, matrix-failure tendency, mechanical suitability, and structural heterogeneity. The present results support candidate selection for future Active Pharmaceutical Ingredient-loaded studies but do not constitute validation of drug-release kinetics. Full article

The growing demand for sustainable, natural-based polymeric materials has accelerated research into cellulose-derived gels. Ethyl cellulose (EC) is a promising candidate; however, its high brittleness, limited flexibility, and insufficient water barrier properties often require the use of a plasticizer to improve its performance. In this study, we synthesized hydroxylated linseed oil polyol (LPO) and evaluated its performance as a bio-based plasticizer for EC-derived dried gels. LPO was characterized by ¹H NMR, ¹³C NMR and FTIR. In addition, quantitative tests further confirmed high hydroxyl value of 280.36 ± 28.96 mg KOH/g. Incorporating LPO into the EC organogel matrix improved the functional performance of dried gel composites, including their mechanical, water vapor barrier, thermal, and morphological properties. The greatest plasticizing performance was achieved at the highest concentration investigated (30% w/w), with a fivefold increase in elongation at break compared to the pristine EC, together with the lowest WVP value (~13 g·mm·m⁻²·kPa⁻¹·day⁻¹), while maintaining good thermal stability and a smooth, homogeneous surface morphology. In addition, FTIR, SEM, and accelerated aging analyses supported the good compatibility and stability of the EC/LPO system. These effects are attributed to intermolecular interactions between EC chains and LPO. Overall, LPO is demonstrated to be an effective bio-based plasticizer for advancing sustainable bioplastic materials, highlighting its potential to replace conventional plasticizers. Full article

Cementation of indirect restorations has undergone a profound change over the past century, evolving from a philosophy of purely mechanical cementation to sophisticated biomaterials science based on adhesion. The aim of this narrative review is to provide essential context for understanding contemporary clinical decision-making. A key aspect is the structural and compositional characteristics of enamel and dentin as bonding substrates, underlining why enamel remains the gold standard, while dentin continues to present significant challenges. The synthesis is based on evidence of adhesive strategies for the four main classes of contemporary restorative materials, such as glass-ceramics (lithium disilicate and leucite), polycrystalline zirconia, resin-matrix ceramics (hybrid ceramics), and indirect composites. Each material was detailed in terms of surface penetration (e.g., hydrofluoric acid etching and air abrasion), chemical coupling (e.g., silanization and MDP-based primers), and appropriate resin cement selection (light-cured, dual-cured, or self-adhesive). A step-by-step clinical protocol is synthesized based on current evidence, integrating critical techniques such as immediate dentin sealing and optimized polymerization. This review concludes that while adhesive resin cements provide predictable long-term results, significant challenges remain, guiding future clinical research and innovation. Full article

To support the achievement of the carbon peaking and carbon neutrality goals and promote the resource utilization of industrial solid waste, a ternary solid waste composite cementitious material was prepared by blending ground granulated blast-furnace slag (GGBFS), fly ash (FA), and carbide slag (CS) with cement. The optimal mix ratio was determined through single-factor experiments and response surface methodology. The synergistic hydration mechanism was elucidated using microstructural characterization techniques, including XRD, FTIR, TG-DTG, and SEM. The composite material was then applied to a semirigid base course, and its mechanical properties and durability were systematically evaluated. The results indicate that the optimal levels of FA, GGBFS, and CS investigated in the single-factor experiments are 20–40%, 30–50%, and 2–6%, respectively. The optimal mix ratio of the ternary solid waste composite is 21.0% FA, 36.3% GGBFS, and 5.7% CS. The underlying microstructural mechanism is that carbide slag creates a highly alkaline environment, which activates the pozzolanic activity of GGBFS and fly ash, leading to the formation of hydration products dominated by C-(A)-S-H gel. With increasing curing age, the gel structure evolves from a loose and disordered state to a dense and ordered state, ultimately forming a compact microstructure based on a highly polymerized C-(A)-S-H gel matrix. The 7-day unconfined compressive strength of the stabilized gravel using the solid waste-based composite cementitious material reached 5.93 MPa, and the 28-day drying shrinkage coefficient was reduced by 18.3% compared with that of cement-stabilized gravel. After 18 freeze–thaw cycles, the compressive strength increased by 2.4%, with the pore structure characterized by a “macropores decreasing, micropores increasing” refinement pattern. After 18 wetting–drying cycles, the cumulative strength loss was 11.26%, outperforming cement-stabilized gravel. Combined with SEM observations, these performance improvements are attributed to the densely intertwined hydration products, particularly C-S-H gel, which effectively fill the voids between aggregate particles and significantly enhance the volume stability, freeze–thaw resistance, and wetting–drying durability of the stabilized gravel. The application of this cementitious material in a semirigid base course demonstrates excellent mechanical and durability properties, providing a theoretical basis and technical support for the widespread application of industrial solid waste in road engineering. Full article

The increasing demand for materials with enhanced properties and high-performance devices has driven substantial research into nanomanufacturing, particularly using carbon nanotubes (CNTs), because of their exceptional properties and high sensitivity to chemical doping. In this way, this work summarizes nanomanufacturing methods for CNT-based devices developed in Brazil, covering the complete cycle from nanocomposite production to functional device assembly across cellulosic, polymeric, and metallic matrix systems. For cellulosic matrices, vacuum filtration enables the production of buckypaper, which is subsequently assembled into chemiresistive, thermoresistive, and thermoelectric devices. For polymeric matrices, 3D printing combined with surface functionalization techniques (spray coating, inverted immersion, and direct immersion) produces piezoresistive robotic sensors, metal-free thermal sensors, and biomedical scaffolds for tissue engineering. For metallic matrices, electrodeposition can produce Cu-CNT-coated aluminum comparable to traditional copper power transmission cables, while arc welding produces stainless steel composites with properties comparable to commercial high-grade steels. These devices have commercial and industrial applications, with low-cost and scalable production methods in comparison with conventional materials. Characterization results demonstrate that CNT integration into diverse matrices successfully bridges nanoscale properties to macroscopic functional devices. Current challenges include uniform CNT dispersion and structural defect control, laboratory to industry scale transition, and long-term device stability under environmental conditions. Future perspectives encompass lab-on-chip systems, wearable devices, 3D-printed smart structures, Internet of Things integration, and machine learning-enhanced analytics. Full article

The remediation of contaminants of emerging concern (CECs) requires innovative, high-efficiency, and sustainable technologies. Here, we investigate active polymeric membranes incorporating TiO₂/ZnO heterojunctions for synergistic sono-enhanced photocatalytic water treatment under both UV and visible-light irradiation. TiO₂/ZnO composites were synthesized and characterized, confirming the formation of type II heterojunctions with tailored optical properties for sunlight-driven photocatalysis. The catalysts were integrated into poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) matrixes using electrospinning (ES) and thermally induced phase separation (TIPS). ES membranes, specifically the ZnO-rich heterojunction within a PVDF-TrFE matrix (3T-7Z@TrFE ES), achieved the highest performance toward ciprofloxacin (CIP) degradation, reaching 71 and 57% under UV and visible light, respectively. The hybridization of the method by coupling ultrasound induced significant synergistic effects, with relative enhancement factors up to 1.38. Furthermore, the sono-enhanced photocatalytic pathway shifted the degradation mechanism towards the early fragmentation of the harmful piperazine ring, yielding a more sustainable degradation process. In addition, the composite membranes showed selective antibacterial activity against S. aureus, making this a multifunctional platform able not only to degrade CECs but also to mitigate membrane fouling. Overall, this work demonstrates the potential of tailored heterojunctions and composite membranes as sustainable platforms for the remediation of recalcitrant CECs in water, highlighting the synergy between photoactivity, piezoelectricity, and mechanistic control. Full article

A biological/synthetic hybrid graft copolymer was obtained by grafting poly(acrylic acid) (PAA, synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization) to amylopectin (AMP). The novel graft copolymer presents amphiphilic properties due to the inherent insolubility of AMP in water and was further utilized as a mediator for the synthesis of gold nanoparticles (AuNPs) following an environmentally friendly in situ procedure. The AMP-g-PAA copolymer formation by the interaction of the PAA end groups with the C(6)-OH groups on an AMP backbone was confirmed by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) and 1D (proton (¹H NMR) and carbon (¹³C NMR) nuclear magnetic resonance, and Distortionless Enhancement by Polarization Transfer (DEPT)) and 2D (correlation (COSY) and heteronuclear single quantum coherence (HSQC)) spectroscopies. The calculated degree of substitution of 1.17 suggests that the grafting was done at one OH from the three in an anhydroglycosidic unit (AGU) (preferably at that in C6 position), with a mean grafting efficiency of 76%. Additional information obtained using thermogravimetric analysis shows that the thermal decomposition of AMP-g-PAA occurs in two steps, with a residual mass of ~16 wt% at 700 °C, higher than AMP or PAA, indicating increased thermal stability of the copolymer. Dynamic and electrophoretic light scattering (DLS and ELS) measurements were used to determine the hydrodynamic size and ionic charge of the AMP-g-PAA self-assemblies in aqueous solution as well as their stability. The AMP-g-PAA was subsequently tested as a reducing agent in the environmentally friendly synthesis of AuNPs in aqueous solution, at different incubation temperatures, reaction duration, and inorganic/polymer weight ratios. The development of the surface plasmon resonance band of AuNPs, observed in UV–vis spectra, was consistently monitored over the reaction time. DLS analysis indicated time-dependent changes in the AuNPs’ particle size distributions, while scanning transmission electron microscopy confirmed that the AuNPs formed at the inorganic/polymer weight ratio of 0.36 and at 60 °C were predominantly well-dispersed, spherical-shaped nanoparticles. The AuNPs synthesized in situ within the copolymer matrix did not introduce additional cytotoxicity compared to the parent copolymer alone, with the composites representing a promising safety baseline for further investigation in biomedical applications. Full article

The growing volume of industrial waste and the need for sustainable material solutions drive the search for cost-effective fillers and energy-efficient processing methods for polymer composites. This study investigates the valorization of brick dust (BD), a fine ceramic waste, as a reinforcing filler for unsaturated polyester resin (UPR), combined with microwave (MW) treatment applied at different stages of composite fabrication. The brick dust was comprehensively characterized using laser diffraction, SEM, EDX, XRD, and FTIR, revealing an environmentally safe aluminosilicate powder with a mean particle size of 3–6 µm, plate-like morphology, and surface hydroxyl groups favorable for matrix interaction. The optimal filler content was found to be 50 phr, which increased flexural strength by 6.5%, flexural modulus by 134%, tensile strength by 11%, and impact strength by 40% compared to neat UPR. Among the MW strategies evaluated, post-curing of the fully polymerized composite for 120 s proved most effective, yielding further improvements in flexural strength (110 MPa, +34.1%), flexural modulus (8250 MPa, +49.7%), impact strength (13.8 kJ/m², +119%), and Shore D hardness (88). MW post-curing also increased the gel fraction from 95.0% to 97.8%, raised the thermal stability index (THRI) from 150.6 to 165.8, and reduced equilibrium water absorption from 0.62% to 0.47% with a reversibility index of 87.5%. Fracture surface analysis confirmed a transition from interfacial debonding to cohesive matrix failure, with ultra-thin polymeric veils replicating the scaly filler structure. These results demonstrate that microwave post-curing synergistically enhances the mechanical, thermal, and moisture-resistant properties of brick dust-filled polyester composites. Full article

With the continuous growth in global energy consumption and the increase in the proportion of energy use attributed to buildings, the development of highly efficient and energy-saving building materials has become necessary for reducing energy demands and greenhouse gas emissions. Phase change materials (PCMs) exhibit great potential for enhancing the thermal inertia of buildings owing to their ability to efficiently absorb and release latent heat during phase transitions. In this study n-hexadecane@ polymethyl methacrylate (16-MMWS-K) microcapsules (where “@” denotes the core-shell encapsulation structure) with a crosslinked structure were successfully prepared via emulsion polymerization, using n-hexadecane as the core material and polymethyl methacrylate as the shell. The prepared microcapsules were incorporated into a cement matrix to fabricate a phase-change energy-storage composite material. The morphology, structure, and thermal properties of the microcapsules, as well as their effects on the thermal and mechanical performance of the cement composites, were systematically investigated. The prepared 16-MMWS-K microcapsules exhibited a well-defined core–shell structure, excellent thermal stability, and a suitable phase-change temperature. Increasing the microcapsule content significantly enhanced the thermal energy storage capacity of the cement composites, reduced thermal conductivity, improved hydrophobicity, and demonstrated effective temperature regulation in building simulation experiments. This study provides both theoretical insight and experimental evidence supporting the practical application of 16-MMWS-K microcapsules in cement composites. The 28-day compressive strength (51.7 MPa) remains acceptable despite higher porosity and slight strength reduction. Full article

Biopolymers (BPs), obtained from urban and agricultural wastes, are known as active principles to manufacture ready-for-use finished products in several sectors of the agriculture and chemical industries. These findings prospect a biowaste-based refinery producing chemical specialities to replace products derived from fossil feedstock. The present paper reports new materials containing BPs. Composite granules containing Poly(Butylene Adipate-Co-Terephthalate (PBAT) as a matrix and BPs as fillers are manufactured by twin-screw extrusion. The granules are used to make single-layer PBAT-BP mulch films by single-screw extrusion and three-layer Starch-PBAT-BP films by blown co-extrusion. The films are tested for mechanical properties, and for structural stability and effects in the in vitro cress germination and the in-field horticulture. The results show that both the films’ effects on plant performance and the films’ structural degradation are regulated by the BP and polymeric matrix release kinetics in the operational germination medium or the field soil, and in turn, that the kinetics depend on the mulch film structural features. The horticulture trials prove that the three-layer mulch films have adequate mechanical strength (25 MPa maximum tensile strength and 520% elongation at break) and about 6 months lifespan to maintain and/or improve the soil protection and crop production (17 t/ha) over the plant seasonal cycle. These findings widen the range of renewable chemical specialities potentially producible by the envisioned biowaste-based refinery. Full article

Background: Thymoquinone (TQ), a bioactive compound derived from Nigella sativa L., exhibits promising antioxidant, anti-inflammatory, and wound-healing properties; however, its clinical application is limited by poor solubility and instability. Methods: In this study, three electrospun nanofiber systems based on different polymeric matrices, PVP (N1), PVP/HPβCD (N2), and PVP/PCL (N3), were developed as potential wound dressing materials for controlled TQ delivery. Results: All formulations produced uniform nanofibrous structures with TQ molecularly dispersed within the polymer matrix, as confirmed by SEM, XRPD, and FTIR analyses. The composition of the nanofibers significantly influenced their physicochemical and functional properties. The N2 system, containing hydroxypropyl-β-cyclodextrin (HPβCD), exhibited the smallest fiber diameter (~208 nm), the fastest drug release, and enhanced antioxidant and anti-inflammatory activity due to improved TQ solubility. In contrast, the N3 system, incorporating polycaprolactone (PCL), formed thicker fibers (~1089 nm) and demonstrated sustained release behavior, the highest mucoadhesion, and the most pronounced wound-healing effect (90% closure after 24 h). Stability studies revealed that HPβCD significantly improved TQ resistance to thermal, humidity, and photolytic degradation, whereas the PVP-based system without stabilizers showed the lowest stability. Principal component analysis (PCA) confirmed that nanofiber performance is governed by two key factors: drug availability and sustained release combined with bioadhesion. Importantly, wound-healing efficiency correlated more strongly with the latter. Conclusions: The results demonstrate that rational design of polymer composition enables modulation of TQ delivery and biological response. Among the tested systems, PVP/PCL nanofibers appear to be the most promising candidates for wound-dressing applications due to their ability to provide sustained drug release and enhance tissue regeneration. Full article

Background/Objectives: Bone infection remains a severe clinical challenge characterized by recurrence, antimicrobial resistance, and high morbidity, driving the search for new therapeutic strategies. Despite advances in developing biomaterials with suitable biocompatibility, biodegradability, and structural properties, the lack of effective antibacterial activity continues to significantly limit the treatment of bone defects. To overcome this issue, we investigated the incorporation of silver-based nanostructures into calcium polyphosphate/alginate (CPP/Alg) matrices as an antibacterial reinforcement strategy for bone-related applications. Methods: Silver nanoparticles (AgNPs) were synthesized in aqueous medium via NaBH₄-mediated chemical reduction, using either alginate (Alg) or sodium polyphosphate (PP) as stabilizing agents, enabling a comparative evaluation of biocompatible polymer- and polyphosphate-stabilized systems. Subsequently, AgNPs were incorporated into calcium polyphosphate/alginate (CPP/Alg) matrices to obtain Ag-containing composites. Results: The AgNPs exhibited spherical morphology, Zeta potential values ranging from −38.7 ± 0.2 to −23 ± 0.3 mV, and hydrodynamic diameters between 25.2 ± 0.2 and 143 ± 5 nm. Structural characterization of the biocomposites by X-ray diffraction confirmed hydroxyapatite as the major crystalline phase, while Raman spectroscopy revealed vibrational bands corresponding to both the inorganic and polymeric components. SEM revealed a dense, rough surface, and ICP-OES analysis confirmed the presence of Ag. Antibacterial activity assays demonstrated effective growth inhibition of Staphylococcus aureus and Staphylococcus epidermidis, with inhibition halos growing with increasing composite dosage. Notably, antibacterial activity was achieved at relatively low Ag contents, underscoring the efficiency of these biocomposites. Conclusions: These findings confirm the effective incorporation of AgNPs into the CPP/Alg matrix and support the classification of composites as promising antibacterial biomaterials for bone regeneration applications. Full article

The presence of residual moisture in tetrahydrofuran (THF) greatly limits its suitability for moisture-sensitive processes, including polymerization, Grignard chemistry, and fine-chemical production, where the allowable water concentration is generally lower than 10 mg/kg. Here, a hierarchical microporous/mesoporous composite adsorbent was prepared via extrusion molding, combining an LTA-type zeolite microporous framework with an amorphous mesoporous matrix. Characterization by XRD, FTIR, SEM, and pore analysis confirmed that the LTA crystal structure was retained while mesopores provided channels for mass transport. Static dehydration tests showed that the composite reduced THF water content from 70 mg/kg to 8.3 mg/kg, compared to 23.4 mg/kg for commercial 3A molecular sieves. The enhanced performance arises from micropores supplying uniform adsorption sites for deep dehydration and mesopores accelerating diffusion. Water vapor adsorption, kinetic and isotherm analyzes, regeneration, and competitive adsorption experiments indicated improved water accessibility and high selectivity, with kinetics described by a double-exponential model. The adsorbent remained stable over six adsorption–regeneration cycles. These results demonstrate that hierarchical microporous/mesoporous structures effectively achieve deep THF dehydration. Full article

Silica dispersion in rubber matrices remains a critical issue due to the polarity mismatch between silica and the rubber phase. This study aimed to synthesize functionalized liquid polyisoprene rubber (F-LIR) and evaluate its role in improving the interfacial interaction between silica and solution styrene–butadiene rubber (SSBR). F-LIR was synthesized by introducing an alkoxysilane-containing functionalizing agent at the termination stage of anionic polymerization. Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (¹H-NMR) were used to confirm the successful introduction of silyl groups at the chain ends of liquid polyisoprene. The optimal loading of F-LIR in SSBR was evaluated through bound rubber content, dynamic mechanical analysis, and mechanical performance testing. The results demonstrated that F-LIR improved the tensile strength, modulus at 300% elongation, and bound rubber content of SSBR composites. These enhancements are attributed to the reaction between the silyl groups of F-LIR and surface hydroxyl groups of silica, together with the co-crosslinking interaction between F-LIR and SSBR. The composites containing 4 phr F-LIR exhibited the best overall balance of properties. This study provides a novel method for synthesizing F-LIR, which bridges silica and the rubber matrix by enhanced filler–rubber interactions at the filler–rubber interface. Full article

With the miniaturization of electronic devices, the demand for high-efficiency thermal management materials has become increasingly urgent. Although traditional high-filler random blending composites can enhance thermal conductivity, they often do so at the expense of mechanical properties and lightweight advantages. Therefore, constructing oriented thermal conduction networks at low filler loadings has become a core challenge in current research. This study proposes an interface engineering strategy based on a tannic acid (TA) molecular bridging layer to modify silicon carbide (SiC). By leveraging the self-polymerization and strong adhesion properties of TA, a dense fish scale SiC coating was formed on the surface of highly oriented woven cellulose acetate (WF) through a simple impregnation process. After compositing with a polyurethane (PU) matrix, the obtained WF/TA/SiC/PU exhibits anisotropic thermal conductivity. It has an axial thermal conductivity of 0.44 W/mK, an increase of 411% over PU, and the decomposition temperature has increased by 18.2 °C. Additionally, the composite axial thermal response rate significantly outperforms both the radial direction and PU. This research demonstrates a new approach for achieving high-efficiency thermal management at low filler loadings, providing a scalable pathway for the development of sustainable, lightweight, and high-performance anisotropic heat dissipation devices. Full article