Search Results (2,645)

The growing demand for sustainable materials has intensified research on biodegradable polymers, particularly poly(ε-caprolactone) (PCL), poly(lactic acid) (PLA), and their blends. PLA and PCL offer biocompatibility and biodegradability, making them attractive for biomedical, packaging, and agricultural applications; however, their practical utility remains limited owing to intrinsic drawbacks. PLA has low impact strength and poor thermal resistance, while PCL suffers from low tensile strength and slow degradation kinetics. Blending PLA with PCL can complement their properties, providing a tunable balance of stiffness and flexibility. Further improvements can be achieved through the incorporation of micro- and nanocellulose (NC), which act as reinforcements, nucleating agents, as well as compatibilizers. We critically examine fabrication strategies for NC-reinforced PLA, PCL, and their blends, highlighting NC extraction, surface modification, processing strategies, and dispersion techniques that prevent agglomeration and facilitate uniform distribution. Comparative insights into composite and nanocomposite systems reveal that NC incorporation significantly enhances mechanical properties, thermal resistance, crystallization, and biodegradation kinetics, particularly at low filler loadings, owing to its high surface area, specific strength, and hydrophilicity. The review underscores the potential of PLA/PCL-based nanocomposites as eco-friendly biomaterials with tunable properties tailored for diverse sustainable applications. Full article

Biofilm growth on silicone (Si) medical devices is routinely treated with antibiotics or device removal; however, new approaches are needed. The current work evaluates photothermal therapy (PTT) to augment antibiotic efficacy or directly ablate Staphylococcus aureus biofilms. The semiconducting polymer, Poly [4,4-bis(2-ethylhexyl)-cyclopenta [2,1-b;3,4 b’]dithiophene-2,6-diyl-alt22,1,3-benzoselenadiazole-4,7-diyl] (PCPDTBSe), with a high photothermal conversion efficiency of 53.2%, was formulated into nanoparticles (BSe NPs) and incorporated into Si. Nanocomposites were stimulated with 800 nm light to generate mild hyperthermic conditions of 42 °C, or ablative temperatures above 50 °C. PTT, with or without antibiotics, was deployed against two strains of Staphylococcus aureus biofilms, Xen 29 and Xen 40, followed by an evaluation of bacterial survival, biofilm regrowth, and differential disruption of specific biofilm components. Mild hyperthermia was also used in an in vivo model of silicone implant infection. The results demonstrate a 55–59% reduction in S. aureus when PTT plus antibiotic was used in vitro, and a 51% reduction in vivo. Higher temperatures effectively eradicate both Xen 29 and Xen 40 strains, with a longer exposure time using lower laser power being optimal. Hyperthermia inhibited biofilm regrowth in both strains, resulting in a > 3 log reduction, plus increased dead cells, polysaccharides, and eDNA in treated Xen 40 biofilms. These experiments demonstrate that nanocomposite-based PTT can both reduce viable bacteria and alter individual biofilm components. Full article

The present paper focuses on the effect of carbon nanotubes (CNTs) on the rheological behavior of polyethylene/polypropylene (PE/PP) blends to improve PE/PP mixtures for industrial applications. In our research, 40 wt% HDPE-60 wt% PP blends were produced by extrusion, and 0.59%, 1.18%, and 2.35% multiwalled carbon nanotubes (MWCNTs) were added. Oscillation rheometry was used to study the HDPE-PP-MWCNT nanocomposites and the unfilled polymers at temperatures of 210, 220, 230, 240, and 250 °C in the angular frequency range of 0.05–628.32 rad/s, with 5% deformation. It was demonstrated that in the presence of CNTs, both the complex viscosity and modulus values increase above the percolation threshold. Additionally, it was observed that the crossover modulus (Gx) for all mixtures decreases with increasing temperature. In addition, at 1.18% CNT content, a second crossover appears at all temperatures, and its value increases with temperature. Full article

Atom transfer radical polymerization (ATRP) is a leading reversible deactivation radical polymerization method. It has become an emerging technology to synthesize well-defined, tailor-made polymers, promoting the development of advanced materials (e.g., bioconjugates and nanocomposites) with precisely designed and controlled macromolecular architectures. ATRP-produced polymers or polymeric materials have been successfully applied in the fields of drug delivery, tissue engineering, sample separation, environmental monitoring, bioimaging, clinical diagnostics, etc. In this review, we systematically summarize the progress of ATRP-based chemical and biological sensors in different application fields, including ion sensing, small-molecule detection, bioimaging, and signal amplification for biosensors. Finally, we briefly outline the prospects and future directions of ATRP. This review is expected to provide a fundamental and timely understanding of ATRP-based sensors and guide the design of novel materials and methods for sensing applications. 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

Epoxy resin coatings are widely employed for steel protection owing to their excellent adhesion, chemical stability, mechanical strength, and barrier properties. However, conventional bisphenol A-based resins and organic solvents may pose risks to reproductive, developmental, and immune systems, as well as contribute to atmospheric pollution. This mini-review critically evaluates recent advancements in fully waterborne bio-based epoxy nanocomposites as sustainable alternatives, with particular emphasis on their enhanced antibacterial and corrosion-resistant performance in tropical marine environments. A central focus is the role of chitosan-grafted graphene oxide (Chi-GO) as a multifunctional nanofiller that significantly enhances both antibacterial efficacy and barrier capabilities. For instance, coatings reinforced with Chi-GO exhibit up to two orders of magnitude lower corrosion current density than pristine epoxy coatings, and achieve over 95% bacterial inhibition against Escherichia coli and Staphylococcus aureus at a 1 wt.% loading. The review summarizes key synthesis methods, functional modification techniques, and commonly adopted evaluation approaches. Emerging research further underscores environmental performance metrics, including reduced volatile organic compound (VOC) emissions and improved life-cycle assessments. By integrating bio-based polymer matrices with Chi-GO, these composite systems present a promising pathway toward environmentally benign and durable protective coatings. Nevertheless, critical challenges concerning scalability and long-term stability under real-world operating conditions remain insufficiently addressed. Future research should emphasize scalable manufacturing strategies, such as roll-to-roll processing, and conduct extended tropical exposure testing (e.g., salt spray tests beyond 2000 h). Additionally, developing comprehensive life-cycle assessment (LCA) frameworks will be crucial for sustainable industrial implementation. Full article

The production of polymer nanocomposites from supertough blends reinforced with carbon-based nanofillers has garnered attention in recent years due to improvements in their mechanical, thermal, and electrical properties. Currently, the main challenge is to develop materials with balanced performance for diverse industrial demands. In this context, this work aimed to produce nanocomposites of poly(butylene terephthalate) (PBT) and poly(ethylene-octene) grafted with glycidyl methacrylate (POE-g-GMA), reinforced with carbon nanotubes (MWCNTs). The PBT, the PBT/POE-g-GMA blend, and the respective MWCNT nanocomposites were initially premixed in an internal mixer and then processed in a co-rotational twin-screw extruder. After processing, they were injection-molded to obtain tensile, impact, and HDT test specimens. Mechanical (tensile, impact, and Shore D hardness), thermal (differential scanning calorimetry—DSC), thermomechanical (heat deflection temperature—HDT), electrical resistivity/conductivity, morphology, and Fourier transform infrared spectroscopy (FTIR) properties were evaluated. The results demonstrated a good balance among the investigated properties, with improvements in mechanical, thermal, and thermomechanical properties when compared to PBT. The impact strength of the nanocomposites reached 186 J/m, approximately 158% higher than that of neat PBT. The HDT reached approximately 55 °C in the PBT/POE-g-GMA/MWCNT5 nanocomposites, while the crystallization temperature increased by 11 °C, as evidenced by DSC, an aspect of great relevance for industrial applications. Furthermore, the PBT/POE-g-GMA/MWCNT5 nanocomposites exhibited an electrical conductivity of 1.06 × 10⁻⁷ S/cm, indicating potential for electrical applications. Full article

A comprehensive investigation was conducted focusing on two series of poly(lactic acid) (PLA)-based nanocomposites filled with small amounts (0.5 and 1.0%) of metal (Ag/Cu) nanoparticles (NPs). Our work aimed to synthesize PLA/Ag nanocomposites via in situ ring-opening polymerization (ROP), and for comparison purposes, the same materials were also prepared via solution casting followed by melt mixing. PLA/Cu nanocomposites were also prepared via melt extrusion. Gel permeation chromatography (GPC) and intrinsic viscosity measurements [η] showed that the incorporation of Ag nanoparticles (AgNPs) resulted in a decrease in the molecular weight of the PLA matrix, indicating a direct effect of the AgNPs on its macromolecular structure. Fourier-transform infrared spectroscopy (FTIR) revealed no significant changes in the characteristic peaks of the nanocomposites, except for an in situ sample containing 1.0 wt% of AgNPs, where slight interactions in the C=O region were detected. Differential scanning calorimetry (DSC) analysis confirmed the semi-crystalline nature of the materials. Glass transition temperature was strongly affected by the presence of NPs in the case of the in situ-based samples. Melt crystallized studies suggested potential indirect polymer–NP interactions, while isothermal melt crystallization experiments confirmed the nucleation ability of the NPs. The mechanical performance was assessed via tensile and flexural measurements, revealing that the in situ-based samples exhibited remarkable flexibility. Moreover, during the three-point bending tests, none of the in situ nanocomposite samples broke. In this context, next-generation PLA-based nanocomposites have been proposed for advanced applications, including flexible printed electronics. Full article

Shape-memory polymers (SMPs) are a unique class of smart materials capable of recovering their original shape upon external stimuli, with thermoresponsive polyurethane (PU) being one of the most widely studied systems. However, the relatively low mechanical strength, thermal stability, and durability of PU limit its broader functional applications. PU/ND composites containing 0.1–0.5 wt.% ND were fabricated via melt blending and injection molding method. The objective was to evaluate the effect of ND reinforcement on the mechanical, scratch, thermal, rheological, and shape-memory properties. Results show that tensile strength increased up to 114% and Young’s modulus by 11% at 0.5 wt.% ND, while elongation at break decreased due to restricted chain mobility. Hardness improved by 21%, and scratch resistance was significantly enhanced, with the coefficient of friction reduced by 56% at low loads. Thermal stability was improved, with the maximum degradation temperature shifting from 350 °C (pure PU) to 362 °C (0.5 wt.% PU/ND) and char yield increasing by 34%. DSC revealed an increase in glass transition temperature from 65 °C to 68.6 °C. Rheological analysis showed an 89% reduction in damping factor (tan δ), indicating enhanced elasticity. Shape-memory tests confirmed notable improvements in both shape fixity and recovery ratios across successive cycles compared to neat PU, with the highest enhancements observed for the 0.5 wt.% PU/ND nanocomposite—showing up to 7.6% higher fixity and 32% higher recovery than pure PU. These results demonstrate that ND reinforcement effectively strengthens PU while preserving and improving its shape-memory behavior, making the composites promising candidates for high-performance smart materials in sensors, actuators, and aerospace applications. Full article

Exhaled breath analysis is emerging as one of the most promising non-invasive strategies for the early detection of life-threatening diseases, especially lung cancer, where rapid and reliable diagnosis remains a major clinical challenge. In this study, we designed and optimized an electronic nose (e-nose) platform composed of quantum resistive vapor sensors (vQRSs) engineered by polymer-carbon nanotube nanocomposites via spray layer-by-layer assembly. Each sensor was tailored through specific polymer functionalization to tune selectivity and enhance sensitivity toward volatile organic compounds (VOCs) of medical relevance. The sensor array, combined with linear discriminant analysis (LDA), demonstrated the ability to accurately discriminate between cancer-related biomarkers in synthetic blends, even when present at trace concentrations within complex volatile backgrounds. Beyond artificial mixtures, the system successfully distinguished real exhaled breath samples collected under challenging conditions, including before and after smoking and alcohol consumption. These results not only validate the robustness and reproducibility of the vQRS-based array but also highlight its potential as a versatile diagnostic tool. Overall, this work underscores the relevance of nanocomposite chemo-resistive arrays for breathomics and paves the way for their integration into future portable e-nose devices dedicated to telemedicine, continuous monitoring, and early-stage disease diagnosis. Full article

The need for new strategies to reduce the susceptibility of polymeric materials to bacterial colonization is growing, especially with the emergence of drug-resistant bacterial strains. Antimicrobial agents used to modify polymers should not only be effective against microorganisms in both planktonic and biofilm states but also be safe and environmentally friendly. Phytochemicals, which are components of essential oils, may be a suitable choice to help combat microbial resistance to antibiotics. Furthermore, they meet the requirements of green chemistry. Essential oils synthesized by plants as secondary metabolites are capable of combating both Gram-positive and Gram-negative bacteria by disrupting lipid bilayers, affecting efflux pumps, compromising the integrity of bacterial cell membranes, and inhibiting the quorum-sensing system. They are also effective as adjuvants in antibiotic therapies. In this review, we outline the mechanism of action of various essential oil components that resulted in enhanced eradication of planktonic bacteria and biofilms. We summarize the use of these antimicrobial agents in macromolecular systems (nanovessels, fibers, nanocomposites, and blends) and provide an overview of the relationship between the chemical structure of phytochemicals and their antimicrobial activity, as well as their influence on the properties of polymeric systems, with a special focus on green active packaging materials. Full article

 This review comprehensively examines nanocomposite packaging materials for food preservation, focusing on their preparation methods, functional properties, applications, and safety considerations. Nanocomposites, incorporating nanomaterials such as metal nanoparticles, polysaccharides, or essential oils into polymer matrices, demonstrate enhanced mechanical strength, barrier properties (e.g., reduced water vapor and oxygen permeability), and significant antimicrobial activity. These advancements address critical food spoilage challenges by extending shelf life and maintaining quality in diverse products like fruits, vegetables, meats, and dairy. In addition, this review highlights concerns regarding potential cytotoxicity and migration of nanoparticles, underscoring the need for rigorous safety evaluations. While current methods (e.g., ionic gelation, electrospinning) show promise, scalability remains limited. Future research should prioritize eco-friendly designs, functional integration, and standardized safety protocols to facilitate commercial adoption.  Full article

This study explores the development of a water-based hybrid thermoelectric (TE) material composed of Sb₂Te₃ nanoparticles (NPs) and polyethylene oxide (PEO). Sb₂Te₃ NPs were synthesized via the microwave-assisted colloidal route, where X-ray diffraction confirmed the purity and quality of the Sb₂Te₃ NPs. Key properties, including the Seebeck coefficient (S), electrical conductivity (σ), power factor (PF), and long-term stability, were studied. X-ray photoelectron spectroscopy (XPS) analysis revealed that exposure to water and oxygen leads to NP oxidation, which can be partially mitigated by hydrochloric acid (HCl) treatment, though this does not halt ongoing oxidation. Scanning electron microscopy (SEM) images displayed a percolation network of NPs within the PEO matrix. While the initial σ was high, a decline occurred over eight weeks, resulting in similar conductivity among all samples. The effect of surface treatments, such as 1,6-hexanedithiol (HDT), was demonstrated to enhance long-term stability. The results highlight both the challenges and potential of Sb₂Te₃/PEO hybrids for TE applications, especially regarding oxidation and durability, and underscore the need for improved synthesis and processing techniques to optimize their performance. This study provides valuable insights for the design of next-generation hybrid TE materials and emphasizes the importance of surface chemistry control in polymer–inorganic nanocomposites. Full article

The thermal behavior of 3D-printed polyvinylidene fluoride (PVDF)-based composites enhanced with carbon nanotubes (CNTs), graphene nanoplatelets (GNPs), and their hybrid formulations was investigated under Joule heating at applied voltages of 2, 3, and 4 V. The influence of filler type and weight fraction on both electrical and thermal conductivity was systematically assessed using a Design of Experiments (DoE) approach. Response Surface Methodology (RSM) was employed to derive an analytical relationship linking conductivity values to filler loading, revealing clear trends and interaction effects. Among all tested formulations, the composite containing 6 wt% of GNPs exhibited the highest performance in terms of thermal response and electrical conductivity, reaching a steady-state temperature of 88.1 °C under an applied voltage of just 4 V. This optimal formulation was further analyzed through multiphysics simulations, validated against experimental data and theoretical predictions, to evaluate its effectiveness for potential practical applications—particularly in de-icing systems leveraging Joule heating. The integrated experimental–theoretical–numerical workflow proposed herein offers a robust strategy for guiding the development and optimization of next-generation polymer nanocomposites for thermal management technologies. Full article

Thorium has emerged as a promising alternative to uranium in nuclear energy systems due to its higher natural abundance, favorable conversion to fissile ²³³U, and reduced generation of long-lived transuranic waste. This review provides a comprehensive overview of advanced techniques for thorium recovery from primary ores and secondary resources. The main mineralogical carriers—including monazite, thorianite, thorite, and cheralite as well as industrial by-products such as rare-earth processing tailings—are critically examined with respect to their occurrence and processing potential. Physical enrichment methods (gravity, magnetic, and electrostatic separation) and hydrometallurgical approaches (acidic and alkaline leaching) are analyzed in detail, highlighting their efficiencies, limitations, and environmental implications. Particular emphasis is placed on modern separation strategies such as solvent extraction with organophosphorus reagents, diglycolamides, and ionic liquids, as well as extraction chromatography, nanocomposite sorbents, ion-imprinted polymers, and electrosorption on carbon-based electrodes. These techniques demonstrate significant progress in enhancing selectivity, reducing reagent consumption, and enabling recovery from low-grade and secondary feedstocks. Environmental and radiological aspects, including waste minimization, immobilization, and regulatory frameworks, are discussed as integral components of sustainable thorium management. Finally, perspectives on hybrid technologies, digital process optimization, and economic feasibility are outlined, underscoring the need for interdisciplinary approaches that combine chemistry, materials science, and environmental engineering. Collectively, the analysis highlights the transition from conventional practices to integrated, scalable, and environmentally responsible technologies for thorium recovery. Full article