Search Results (917)

High-voltage equipment imposes increasingly stringent demands on polymeric insulating materials, particularly in terms of dielectric strength, space charge suppression, thermo-electrical stability, and interfacial reliability. Conventional polymers are prone to critical failure modes under high electric fields, including electrical treeing, partial discharge, interfacial degradation, and thermo-oxidative aging. This review systematically summarizes recent advances in polymer modification strategies specifically designed for high-voltage applications, covering nanofiller reinforcement, plasma surface engineering, and the development of self-healing insulating polymers. Multi-scale structural control and interface engineering, aligned with the specific requirements of high-voltage environments, have emerged as pivotal approaches to enhance insulation performance. Moreover, the integration of artificial intelligence-driven materials design, digital characterization, and application-oriented modeling holds significant promise for accelerating the development of next-generation high-voltage polymeric systems, thereby offering robust materials solutions for the reliable long-term operation of high-voltage equipment. Full article

The mechanical behavior of carbon-fiber-reinforced polymer (CFRP) laminates manufactured using plasma-assisted solvolysis recycled fibers was evaluated experimentally through a comprehensive mechanical testing campaign. The plasma-assisted solvolysis parameters were selected based on an earlier sensitivity analysis. Prepregs made from both virgin and recycled carbon fibers were fabricated via a hand lay-up process and manually stacked to produce unidirectional laminates. Longitudinal tension tests, longitudinal compression tests, and interlaminar shear strength (ILSS) tests were performed to assess the fundamental mechanical response of the recycled laminates and quantify the retention of mechanical properties relative to the virgin-reference material. Prior to mechanical testing, all laminates underwent ultrasonic C-scan inspection to assess manufacturing quality. While both laminate types exhibited generally satisfactory quality, the recycled-fiber laminates showed a higher density of defects. The recycled laminates preserved around 80% of their original tensile strength and maintained an essentially unchanged elastic modulus. Compressive strength was more susceptible to imperfections introduced during remanufacturing, with the recycled laminates exhibiting roughly a 14% decrease compared with the virgin material. On the contrary, the compressive modulus was largely retained. The most substantial reduction occurred in ILSS, which dropped by 58%. Overall, the results demonstrate that plasma-assisted solvolysis enables the recovery of carbon fibers suitable for remanufacturing CFRP laminates, while the observed reduction in mechanical properties of recycled CFRPs is mainly attributed to defects in manufacturing quality rather than to intrinsic degradation of the recycled carbon fibers. Full article

Herein, we propose a simple and cost-effective method for fabricating moderate-sensitivity surface-enhanced Raman scattering (SERS) substrates using Cu-plasma polymer fluorocarbon (Cu-PPFC) nanocomposite films fabricated through RF sputtering. The use of a composite target composed of carbon nanotube (CNT), Cu, and polytetrafluoroethylene (PTFE) powders (5:60–80:35–15 wt%) offers the advantage of the simple fabrication of moderate-sensitivity SERS substrates with a single cathode compared to co-sputtering. X-ray photoelectron spectroscopy (XPS) revealed that the film surface was partially composed of metallic Cu with Cu-F bonds and Cu–O bonds, confirming the coexistence of the conducting and plasmon-active domains. UV-VIS spectroscopy revealed a distinct absorption peak at approximately 680 nm, indicating the excitation of localized surface plasmon resonances in the Cu nanoclusters embedded in the plasma polymer fluorocarbon (PPFC) matrix. Atomic force microscopy and grazing incidence small-angle X-ray scattering analyses confirmed that the Cu nanoparticles were uniformly distributed with interparticle distances of 20–35 nm. The Cu-PPFC nanocomposite film with the highest Cu content (80 wt%) exhibited a Raman enhancement factor of 2.18 × 10⁴ for rhodamine 6G, demonstrating its potential as a moderate-sensitivity SERS substrate. Finite-difference time-domain (FDTD) simulations confirmed the strong electromagnetic field localization at the Cu-Cu nanogaps separated by the PPFC matrix, corroborating the experimentally observed SERS enhancement. These results suggest that a Cu-PPFC nanocomposite film, easily fabricated using a composite target, provides an efficient and scalable route for fabricating reproducible, inexpensive, and moderate-sensitivity SERS substrates suitable for practical sensing applications. Full article

Fibrous polycaprolactone-based composite materials with the addition of hardystonite (1, 3, and 5 wt.%) were developed using the electrospinning method. The obtained PCL and PCL-HT nonwovens were evaluated in terms of their physiochemical properties (SEM, EDS, BET, and zeta potential). Furthermore, the antioxidant potential [measured by thiobarbituric acid reactive substance (TBARS) levels], blood plasma coagulation parameters, and cyto- and genotoxicity towards PBM and Hs68 cells were assessed to determine the biochemical activity of the composites. The conducted experiments confirmed that hardystonite was successfully incorporated into the PCL matrix. No substantial changes in the fibres’ surface morphology and the structure of the composites were observed. Similarly, the specific surface area, total pore volume, and average pore size did not change significantly. The addition of hardystonite to the polymer solution resulted in a shift in zeta potential toward less negative values. With regard to plasma coagulation parameters, no significant changes were observed in the aPTT, PT, or TT, likely due to the counterbalancing effect of Zn²⁺ and Ca²⁺ ions. Furthermore, the PCL-HT composites exhibited a lowered TBARS level, suggesting antioxidant properties, which could be attributed to the presence of zinc in hardystonite. The PCL and PCL-HT composites demonstrated no cytotoxic or genotoxic effects on the tested blood or skin cell types, suggesting their safety. Full article

Polyhydroxybutyrate (PHB) is considered a coating material capable of limiting the corrosion of biodegradable metallic implants due to its biocompatibility and ability to form a physical barrier. In this study, PHB was deposited on commercial AZ91D magnesium alloy using the spin coating technique. To improve adhesion at the polymer–substrate interface, the magnesium substrates were subjected to atmospheric pressure plasma treatment for different exposure times (5, 10, or 15 min) before coating. The optimal treatment time of 5 min significantly increased substrate wettability and surface free energy, facilitating stronger PHB adhesion. In addition, the PHB coatings were subjected to atmospheric pressure plasma treatment for 5, 10, or 15 s to evaluate potential surface modifications. Corrosion behavior under simulated physiological conditions was assessed via potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in HANK’s solution at 37 °C. Pull-off tests were used to evaluate the adhesion strength between the coating and the substrate under each treatment condition. The results showed a significant decrease in the corrosion rate (V_corr), from 4.083 mm/year for bare Mg-AZ91D to 0.001 mm/year when both the substrate and the polymer received plasma treatment. This indicates that the treatment modifies surfaces and improves interfacial bonding, enhancing polymer–metal interaction and producing durable, biocompatible coatings for medical implants. Full article

Microplastics (MPs) have emerged as persistent environmental pollutants with adverse effects on ecosystems and human health. Conventional removal methods, such as filtration and sedimentation, primarily rely on physical separation without addressing the degradation of MPs, leading to their accumulation and the risk of secondary pollution. This review explores the potential of advanced oxidation processes (AOPs), including photocatalysis, electrochemical oxidation, Fenton processes, sulfate radical-based oxidation, sonochemical treatment, ozonation, and plasma technologies, which generate reactive oxygen and nitrogen species capable of promoting polymer chain scission, microbial biodegradation, and the oxidative fragmentation and mineralization of MPs into non-toxic byproducts. Hybrid AOP systems combined with biological treatments or membrane-based filtration are also examined for their effectiveness in degrading MPs, as well as for scalability and the environmental impacts of their byproducts when integrated into existing wastewater treatment systems. The review further discusses challenges related to operational parameters, energy consumption, and the formation of secondary pollutants. By identifying current knowledge gaps and future research directions, this review provides insights into optimizing AOPs and integrations of AOPs with biological treatments or membrane-based processes for sustainable MP remediation and water treatment applications. Full article

The increasing threat posed by micrometeoroids and orbital debris to in-orbit spacecraft necessitates the development of lightweight and deformable shielding systems capable of withstanding hypervelocity impacts. Ultra-high-molecular-weight polyethylene (UHMWPE) films, owing to their high specific strength and energy-absorption capacity, present a promising candidate for such applications. However, the hypervelocity impact response of thin, highly oriented UHMWPE films—distinct from bulk plates or composites—remains poorly understood, particularly for micron-scale particles at velocities relevant to space debris (≥8 km/s). In this study, we systematically investigate the impact resistance of 0.1 mm UHMWPE films using a plasma-driven microparticle accelerator and a hypervelocity dust gun to simulate impacts by micron-sized Al₂O₃ and Fe particles at velocities up to ~8.5 km/s. Through detailed analysis of crater morphology via scanning electron microscopy, we identify three distinct damage modes: plastic-dominated craters (Type I), fracture-melting craters (Type II), and perforations (Type III). These modes are correlated with impact energy and particle size, revealing the material’s transition from large-scale plastic deformation to localized thermal softening and eventual penetration. Crucially, we provide quantitative penetration thresholds (e.g., 2.25 μm Al₂O₃ at 8.5 km/s) and establish a microstructure-informed damage classification that advances the fundamental understanding of UHMWPE film behavior under extreme strain rates. Our findings not only elucidate the energy-dissipation mechanisms in oriented polymer films but also offer practical guidelines for the design of next-generation, flexible spacecraft shielding systems. Full article

Dielectric barrier discharge (DBD) plasma provides a solvent-free and energy-efficient approach for the in situ polymerization of styrene on cotton textiles. Traditional methods for polystyrene (PS) coating often require elevated temperatures, chemical initiators, or organic solvents, conditions that are incompatible with porous, heat-sensitive substrates such as cotton. In this work, we demonstrate that DBD plasma can initiate and sustain styrene polymerization directly on cotton fibers under ambient conditions. FT-IR spectroscopy confirms the consumption of the vinyl C=C bond and the formation of atactic, amorphous polystyrene. Thermogravimetric analysis indicates that the cotton coated with DBD polymerized PS exhibits enhanced thermal stability compared to cotton coated with commercial PS. Additionally, UV aging tests confirm that the plasma-deposited coating maintains its hydrophobicity after exposure to light. Together, these findings highlight DBD plasma as a sustainable and effective approach for producing hydrophobic, thermally robust, and UV-stable textile coatings without the need for solvents, initiators, or harsh processing conditions. Full article

Three-dimensional ZnO structures were prepared by both thermal atomic layer deposition (ThALD) and plasma-enhanced atomic layer deposition (PEALD) on a sacrificial cellulose template. The synthetic approach consisted of ALD of conformal ZnO nanofilms on the fibrous cellulose template, followed by thermal removal of the polymer. The resulting calcinated samples, consisting of a scaffold of fused polycrystalline ZnO nanoparticles, showed a sevenfold and ninefold increase in photocatalytic activity against methyl orange under ultraviolet-A light, for the ThALD and PEALD samples, respectively, compared to the non-calcined samples prior to cellulose removal. In addition to the improved three-dimensional surface exposure and accessible active sites, it was suggested that the amount of hydroxyl groups on the surface and the density of nanoparticle packing in 3D ZnO structures are critical parameters for improving the photoinduced degradation of the dye. Full article

Natural fibers are increasingly used as sustainable, lightweight, and low-cost alternatives to glass fibers in polymer composites. However, their inherent hydrophilicity and surface polarity limit compatibility with non-polar polymer matrices. Both gas/solid and plasma fluorination modify only the surface of lignocellulosic materials. Mild conditions are mild, with reactivity governed by fluorine concentration, temperature, and material composition. Surface energy is typically assessed through contact-angle measurements and surface analytical techniques that quantify changes in hydrophobicity and chemical functionalities. In wood, fluorination proceeds preferentially in lignin-rich regions, making lignin a key component controlling reactivity and the spatial distribution of fluorinated groups. Natural fibers follow the same logic as for flax, which is a representative example of lignin content. Applications of fluorinated bio-based materials include improved moisture resistance, enhanced compatibility in composites, and functional surfaces with tailored wetting properties. Scalability depends on safety, cost, and process control, especially for direct fluorination. Durability of the treatment varies with depth of modification, and environmental considerations include the potential release of fluorinated species during use or disposal. Full article

Polyethylene (PE) films are widely used as waterproofing materials on the surfaces of metal pipelines. Poor adhesion of PE films to a metal substrate reduces durability, leading to shorter service life and higher economic costs. The current research aims to study the modification of PE films in atmospheric pressure gliding arc plasma (GAP). The adhesion properties of the modified films were investigated using the contact angle method and adhesion work calculations. During the modification process, the GAP treatment duration and deflector nozzle angle of attack were optimized to 10 s and 135°, respectively. It was established that the adhesion work increased from 62.1 to 141.3 mJ/m² after 10 s GAP modification compared to untreated PE. GAP modifying of PE films for 30 s or more is impractical, as the increase in the adhesion work ceases after that. It was found that surface roughness R_max increased by up to 4.1 times after 10 s GAP modification compared with nontreated PE. The PE films acquired hydrophilic properties after plasma modification, due to changes in the polymer surface’s chemical structure. The results of IR spectroscopy studies indicated oxidation of the film surface, an increase in the concentration of surface polar groups (-COOH, OH, C=O), and the formation of double bonds (C=C), which led to improved adhesive properties. A study of the electret properties showed that the observed decline and subsequent stabilization of values occurred within the first 24 h. Mechanical tests indicated improved performance of the GAP-modified PE films compared to the non-treated ones in the PE–mastic–PE and PE–mastic–steel systems. Due to their enhanced contact properties, the modified PE films are of interest as a base material for creating waterproofing materials. Full article

The microbial resistance era prompts researchers to find new effective antimicrobial agents. Trimetallic nanocomposites consisting of AuAg nanostructures and iron oxide nanoparticles can represent an efficient tool to inhibit bacterial growth as demonstrated here. The trimetallic nanocomposites, prepared by green chemistry approach, are grafted on a modified, plasma-treated, flexible polyethylene terephthalate (PET) substrate. Spectroscopic and microscopic characterization of the trimetallic nanocomposites grafted on modified PET together with antibacterial tests confirm the successful applicability of the newly developed material: a statistically significant antibacterial effect against E. coli is proven. This effect is further pronounced by a short time (5 min) UVA light (365 nm) irradiation. The present work thus reports on the feasible preparation of the brand-new material that is successfully used in E. coli colony growth regulations. The impact of small noble metal nanostructures containing Ag and UVA light-activated iron oxide particles on the bacterium can be combined and results in the improved antibacterial performance of the final material. Employing such material may represent a potential strategy for fighting against the development of bacteria resistance. Full article

Embedding flexible electronic circuits into a sustainable polymer is an emerging and significant topic in the field of in-mold electronics (IME). Ensuring strong adhesion between the flexible circuit and the molded polymer is critical for the durability of IME products. In this study, three different types of etched copper polyimide (PI) foils were used as the substrate of electronic components. Two bio-based and biodegradable polymers of polylactic acid (PLA) and polyhydroxybutyrate (PHB) served as the overmolding material. Four different surface pretreatments: drying, polydopamine (PDA) coating, PDA coating followed by thermal treatment under vacuum, oxygen plasma, and 3-aminopropyltriethoxysilane (APTES) were applied to the PI surface prior to the overmolding process to investigate the influence on the adhesive strength. Additionally, a thermoplastic polyurethane (TPU) adhesive layer was introduced via vacuum lamination to further improve adhesion. The main objective of this study was to evaluate the adhesive strength between etched PI and overmolded biopolymers before and after surface modifications. The loci of failure were analyzed using scanning electron microscopy (SEM). The results indicate that laminated TPU is the most effective approach for improving adhesion between polyimide foils and biopolymers. Full article

This work presents a multifactorial strategy for reusing waste thermoplastics and generating multifunctional filaments for additive manufacturing. Acrylonitrile–butadiene–styrene (ABS) waste and commercial poly(methyl methacrylate) (PMMA) were compounded with carbon black (CB), graphene (G), or graphene foam (GF) at different loadings and extruded into composite filaments. The aim is to couple filler-induced bulk modifications with atmospheric pressure plasma jet (APPJ) surface coatings of TiO₂ and graphene oxide (GO) to obtain waste-derived filaments with tunable morphology, wettability, and thermal stability for advanced 3D-printed architectures. The filaments were subsequently coated with TiO₂ and/or GO using an APPJ process, which tailored surface wettability and enabled the formation of photocatalytically relevant interfaces. Digital optical microscopy and SEM revealed that CB, G, and GF were reasonably well dispersed in both polymer matrices but induced distinct surface and cross-sectional morphologies, including a carbon-rich outer crust in ABS and filler-dependent porosity in PMMA. For ABS composites, static contact-angle measurements show that APPJ coatings broaden the apparent wettability window from ~60–80° for uncoated filaments to ~40–50° (TiO₂/GO) up to >90° (GO), corresponding to a ≈150% increase in contact-angle span. For PMMA/CB composites, TiO₂/GO coatings expand the accessible contact-angle range to ~15–125° while maintaining surface energies around 50 mN m⁻¹. TGA/DSC analyses confirm that the composites and coatings remain thermally stable within typical extrusion and APPJ processing ranges, with graphene showing only ≈3% mass loss over the explored temperature range, compared with ≈65% for CB and ≈10% for GF. Fused deposition modeling trials verify the printability and dimensional fidelity of ABS-based composite filaments, whereas PMMA composites were too brittle for reliable FDM printing. Overall, combining waste polymer reuse, tailored carbonaceous fillers, and APPJ TiO₂/GO coatings provides a versatile route to design surface-engineered filaments for applications such as photocatalysis, microfluidics, and soft robotics within a circular polymer manufacturing framework. Full article

Biodegradable bioplastics have emerged as a promising sustainable alternative to minimize the environmental impact of traditional plastics. Nevertheless, many of them degrade slowly under natural or industrial conditions, raising concerns about their practical biodegradability. This fact is related to the high-order structure of the polymer backbones, i.e., high molar mass and high crystallinity. Research efforts are being devoted to the development of technologies capable of reducing the length of polymer segments by accelerated chain scission, which could help improve biodegradation rates upon disposal of bioplastic products. The objective of this review is to examine the current state of the art of abiotic degradation techniques, physically driven by temperature, mechanical stress, UV/gamma/microwave irradiation, or plasma or dielectric barrier discharge, and chemically induced by ozone, water, or acidic/basic solutions, with the aim of enhancing the subsequent biodegradation of bioplastics in controlled valorization scenarios such as composting and anaerobic digestors. Particular attention is given to pretreatment degradation technologies that modify surface properties to enhance microbial adhesion and enzymatic activity. Technologies such as ozonation and plasma-driven treatments increase surface hydrophilicity and introduce functional groups with oxygen bonds, facilitating subsequent microbial colonization and biodegradation. Irradiation-based techniques directly alter the chemical bonds at the polymer surface, promoting the formation of free radicals, chain scission, and crosslinking, thereby modifying the polymer structure. Pretreatments involving immersion in aqueous solutions may induce solution sorption and diffusion, together with hydrolytic chain breakage in bulk, with a relevant contribution to the ulterior biodegradation performance. By promoting abiotic degradation and increasing the accessibility of biopolymers to microbial systems, these pretreatment strategies can offer effective tools to enhance biodegradation and, therefore, the end-of-life management of bioplastics, supporting the transition toward sustainable cradle-to-cradle pathways within a biocircular economy. Full article