Crystal violet is a cationic dye widely used in biomedical research, industrial dyeing, microbiology, and the textile industry. To remove this toxic dye, which has harmful environmental effects, environmentally friendly composite bioadsorbent spheres were prepared using alginate, a brown seaweed-derived biopolymer, and bioglass. Crystal violet adsorption was performed using a biocomposite adsorbent prepared by adding 14% bioglass to an alginate matrix. The effects of adsorbent amount, dye concentration, contact time, and pH on the adsorption process were investigated. In this study, a maximum removal efficiency of 65.68% was achieved using 40 mg of adsorbent in 20 mL of a 5 mg/L crystal violet solution after 120 min at a stirring speed of 200 rpm. The Langmuir model estimated a theoretical maximum adsorption capacity (qmax) of 5.57 mg/g based on the three investigated initial concentrations (5, 10, and 15 mg/L). The data were analyzed using Response Surface Methodology. ANOVA indicated that contact time had the greatest effect on removal efficiency. Isotherm and kinetic studies revealed that the Langmuir and Dubinin–Radushkevich isotherm models adequately described the adsorption process, and that the second-order kinetic model provided the best fit. These findings suggest that the adsorption is consistent with monolayer adsorption on a relatively homogeneous surface, and that binding may occur via low-energy physical interactions within micropores. The developed bioadsorbents demonstrated promising performance for crystal violet removal.
Polymer nanocomposites have attracted considerable attention owing to their ability to achieve substantial improvements in mechanical, thermal, electrical, barrier, and multifunctional properties through the incorporation of low concentrations of nanoscale fillers. This review provides a comprehensive analysis of recent advances in polymer nanocomposites, focusing on the relationships between nanofiller characteristics, processing strategies, interfacial interactions, and the resulting material performance. Different classes of nanofillers, including carbon-based, ceramic, metallic, polymeric, and hybrid nanostructures, are systematically compared with respect to their morphology, surface chemistry, of processing routes, including melt blending, solution processing, in situ polymerization, and surface functionalization, on nanoparticle dispersion and polymer–nanofiller interfacial adhesion is critically discussed. The review further evaluates how these factors govern the mechanical, thermal, electrical, dielectric, and barrier properties of polymer nanocomposites and summarizes their applications in aerospace, automotive engineering, electronics, biomedical devices, energy systems, construction, and advanced packaging. Current technological challenges, including nanoparticle aggregation, long-term stability, process scalability, environmental impact, and nanomaterial safety, are also examined. Finally, emerging research directions, including hybrid nanofillers, sustainable polymer systems, digital materials design, and machine-learning-assisted optimization of polymer nanocomposites, are highlighted. This review provides an integrated perspective on the design and processing of high-performance polymer nanocomposites and identifies key opportunities for future research and industrial implementation.
In the last few years, the tyre industry has faced new sustainability challenges, mainly regarding the substitution of fossil-based ingredients with bio-based raw materials. In fact, most of the largest tyre companies worldwide have publicly declared the objective of producing tyres with 100% sustainable materials by 2050. The main ingredients in a tyre compound are the polymer matrix and the reinforcing filler, but while natural rubber (NR) already represents a well-established bio-based alternative to synthetic polymers, the replacement of conventional reinforcing fillers remains a significant challenge. In fact, carbon black (CB), a fossil-based raw material produced from petroleum-derived feedstock, is still the main filler used in rubber compounds worldwide. A promising candidate for its replacement could be Microfibrillated cellulose (MFC): a bio-based, biocompatible, renewable, and non-toxic material, also obtained from waste biomass, with a lower density and a higher surface reactivity with respect to CB. However, the polar functional groups on its surface make it extremely incompatible with the non-polar rubber matrices used for tyre formulations. To overcome this limitation, effective compatibility strategies are required to exploit and boost these surface functionalities and promote the formation of a novel filler–polymer network. In this work, a new approach for MFC functionalisation is developed, and the synthesis and characterisation of the modified material are reported. This strategy is further applied to develop innovative MFC-reinforced epoxidised natural rubber (ENR) compounds, whose properties are compared to conventional CB-filled systems.
Slippery liquid-infused porous surfaces (SLIPS) can reduce ice adhesion, but their durability depends on coupled wetting, rheological, and phase-transition effects. Here, seven imidazolium ionic liquids (ILs) with varied alkyl and disiloxane substituents were evaluated as lubricants for laser-textured superhydrophobic aluminum. Surface tension, viscosity, thermal behavior, lubricant retention, wetting, and ice adhesion at −10 °C were correlated over 30 icing-deicing cycles. All freshly prepared coatings were water-wettable but exhibited weak droplet pinning, with sliding angles of 1.4–7.5°, despite apparent water contact angles below 90°. This combination reflects the lubricant-mediated interface, for which droplet mobility is not determined by the static contact angle alone. The behavior of SLIPS with different lubricants diverged under centrifugal loading: low-viscosity ILs were depleted, whereas ILs that solidified under the applied cooling protocol were retained more effectively within the texture. Counterintuitively, greater lubricant retention produced higher ice adhesion because solidified ILs stabilized ice bridges within the surface relief. The lowest adhesion after cycling was obtained for the coating infused with [C9C3Si2Oim][NTf2], which after lubricant depletion restored a superhydrophobic state with a water static contact angle of 171.6 ± 1.6°. These results identify lubricant phase state and interfacial redistribution as key design parameters for durable anti-icing SLIPS.
Flexible anti-collision airbags are lightweight and highly deformable and are used for mitigating vessel–bridge collision loads, while reliable analysis requires accurate descriptions of the mechanical behaviour of the airbag materials. A three-layer single-chamber airbag comprising an inner thermoplastic polyurethane fabric (TPU) and two outer woven ultra-high-molecular-weight polyethylene (UHMWPE) reinforcing layers stitched locally by polyamide webbings is investigated. Uniaxial tensile tests are conducted on TPU and UHMWPE in the warp and weft directions, and anisotropic hyperelastic models are established. Based on model comparison and parameter identification, a three-parameter Yeoh base with a weak orthotropic correction is adopted for TPU, while a neo-Hookean base with a strong orthotropic correction is used for UHMWPE. Comparisons of the numerical and experimental results yield R2 values exceeding 0.9854 for force and 0.9995 for pressure, with relative differences of 4.183% and 0.348% at the maximum compression ratio η=0.7, respectively. The test results show that increasing the initial pressure from 0.12 to 0.14 MPa raises the force and pressure increments by 51.1% and 19.7%, respectively. Numerical analysis indicates that prescribed loading rates up to 10 m/min preserve the quasi-static response at η of 0.7 with less than approximately 1% deviation. At η=0.7, increasing the axial loading length ratio ηL from 0.2 to 0.6 raises the force by 208.7%, while the unit-length force changes by only 7.56%, whereas a larger airbag aspect ratio Λ increases the force but reduces the unit-length force and pressure increment under constant ηL. When the axial eccentricity reaches 0.20, the force and pressure increments rise by 45.5% and 31.3%, respectively. The established models provide a reliable basis for the localized compression analysis of the anisotropic multilayer airbag.
The development of sensitive, low–cost, and visually readable dosimeters for low gamma–ray exposures is important for occupational and environmental radiation monitoring and for other low–dose applications. This work investigates a colorimetric and optical thin–film dosimeter based on polyvinyl alcohol (PVA) containing silver nitrate (AgNO3) and hafnium oxide (HfO2). The film was fabricated using a solution–casting technique. The dosimetric response was evaluated over an absorbed–dose range of 22.2–65.2 mGy using diffuse reflectance spectroscopy, Kubelka–Munk (K/S) analysis, CIELAB colorimetry, CMYK image–based analysis, and X–ray diffraction (XRD). Irradiation produced a dose–dependent decrease in visible reflectance and a corresponding increase in optical absorption. The K/S response increased with dose, while CIELAB analysis showed a systematic decrease in lightness and an increase in total color difference (ΔEab∗), reaching approximately 25 at 65.2 mGy. Linear regression of ΔEab∗ over 0–65.2 mGy gave y = 0.399x − 1.0029 with R2 = 0.9845. CMYK analysis also showed a clear dose response, with the yellow channel (ΔY) exhibiting the largest relative change among the chromatic channels. XRD identified monoclinic HfO2 as the dominant crystalline filler phase and showed dose–associated changes in peak intensity, peak position, and the relative prominence of the broad PVA–related feature. At the highest XRD dose, several HfO2 reflections weakened while the broad contribution near 2θ ≈ 19.9–20° became more prominent. These changes are interpreted as dose–dependent structural modification and partial loss of resolved crystalline order rather than definitive evidence of a newly formed crystalline phase. A surface morphology and microstructure analysis was performed on control and γ–ray–irradiated PVA/HfO2/AgNO3 nanocomposite films using scanning electron microscopy (SEM–EDX). The morphological transition to fibrous, tree trunk–like structures seen by SEM is well correlated with the dose–dependent change in composition to higher surface Ag content, supporting the idea that radiation–induced Ag nanoparticle nucleation and growth is the primary degradation mechanism in the irradiated films. The combined optical and colorimetric results demonstrate a measurable response of the PVA/HfO2/AgNO3 formulation in the investigated low–mGy gamma–ray range.
Polymer Additive Manufacturing (AM) offers substantial opportunities for material-efficient and distributed production, yet its transition towards genuine circularity remains constrained by cumulative material degradation, fragmented recovery strategies, and the limited integration of lifecycle, environmental, economic, and industrial considerations. This critical systematic review examines circularity in polymer AM beyond conventional end-of-life recycling by integrating material behaviour, manufacturing-induced evolution, degradation mechanisms, lifecycle performance and value retention, recovery pathways, and sustainability assessment within a unified systems perspective. Following a PRISMA-based selection process, 3214 records were progressively screened to a final corpus of 175 peer-reviewed studies published between 2015 and 2025. The evidence demonstrates that polymer circularity is not an intrinsic material property, but an emergent lifecycle outcome governed by polymer chemistry, manufacturing history, cumulative degradation, functional-value retention, waste-stream quality, recovery technology, infrastructure, and environmental and economic conditions. Based on this synthesis, the review introduces Intelligent Circular Polymer Additive Manufacturing (ICPAM), a lifecycle-wide framework integrating Design for Circularity, degradation-aware manufacturing, adaptive recovery, digital intelligence, industrial implementation, and continuous feedback. ICPAM further incorporates multi-criteria decision support for selecting context-dependent circular strategies and a qualitative/semi-quantitative maturity assessment for identifying lifecycle bottlenecks and implementation priorities. The resulting framework shifts polymer AM circularity from reactive waste management towards proactive lifecycle engineering, while recognizing that emerging regenerative materials and digital technologies still require substantial industrial validation before their full circular potential can be realized.
A polyurethane coating represents the conventional solution for protecting and finishing visible wooden furniture surfaces. However, the increasing use of additive manufacturing has introduced visible 3D-printed polymer components whose surface mechanical performance is relevant to their application in furniture. This study investigated the effect of short-term exposure to 60 °C for 1 h on the surface mechanical properties of a pigmented polyurethane coating applied to oak wood and 3D-printed PLA, ABS-T and PET-G components. Specimens were evaluated under laboratory conditions (20 °C) and immediately after exposure to 60 °C, while their surfaces remained at an elevated temperature. Impact resistance, abrasion resistance, and scratch resistance using a tungsten carbide tip were determined according to the relevant standards, and the surface damage was assessed by visual inspection and digital microscopy. The polyurethane coating exhibited the smallest impact indentation diameter but showed earlier crack initiation and lower abrasion resistance than the 3D-printed polymers. Among the investigated polymers, ABS-T provided the most balanced combination of impact resistance, abrasion resistance and surface hardness, whereas PLA exhibited the greatest dimensional changes after exposure to 60 °C. Microscopic analysis revealed surface defects that were not detectable by visual inspection, demonstrating the value of digital microscopy for detecting subtle surface damage. The results indicate that ABS-T is a promising material for visible furniture components exposed to short-term elevated temperatures, while PET-G should be used with caution in applications exposed to radiant heat or direct sunlight.
The chemical profile and migration behavior of volatile and semi-volatile compounds from silicone molds intended for use in air fryers were investigated. The study combined migration tests using 10% ethanol, 3% acetic acid, and simulant E (Tenax®) with direct headspace (HS) analysis of the molds by gas chromatography–mass spectrometry (GC-MS). HS analysis and migration tests with aqueous simulants were performed over three heating cycles to simulate repeated use. A non-targeted analytical approach was applied, followed by selective quantification based on toxicological criteria and the relevance of the compounds to the material. A total of 128 substances were identified, including siloxanes and non-intentionally added substances (NIASs). Siloxanes were detected in both simulant E and 10% ethanol. Most NIASs were found at levels below the limit of quantification or within regulatory limits, except for dibutyl phthalate, which exceeded its specific migration limit (0.3 mg kg−1). Furthermore, the sum of migrated cyclic siloxanes in simulant E surpassed the generic specific migration limit (60 mg kg−1) established in Spanish Royal Decree 847/2011, while the release of volatile organic compounds exceeded the recommended value of 0.5%. The results revealed a complex chemical profile characterized by diverse NIASs and elevated migration of cyclic siloxanes in simulant E.
Three-dimensional (3D) printing technology has become more and more popular in restorative dentistry; however, information regarding the mechanical properties of 3D-printed restorative materials remains limited. The aim of this study was to evaluate the behavior under compressive loading until fracture of occlusal veneers fabricated from two types of 3D-printed resin composites, Saremco Print Crowntec A2 and Voco V-Print C&B Temp A2, intended for permanent and temporary clinical restorations, respectively. The study design involved scanning a first upper premolar typodont tooth, previously prepared to receive an occlusal veneer restoration, followed by the computer-aided design of the occlusal veneers and resin dies and 3D printing, resulting in 20 samples. The cemented restorations were subjected to mechanical testing using a fracture-resistance test at a speed of 5 mm/min, applied until failure. The recorded failure forces ranged between 571 and 970 Newton (N), values that are comparable to physiological masticatory forces. The absorbed energy was calculated as the area under the force–displacement curve using the trapezoidal integration method. The mean energy at failure was 0.301 Joule (J) (Voco) and 0.244 Joule (J) (Saremco), with Voco demonstrating greater toughness. In terms of fracture pattern classification, the 3D-printed resin with a lower filler content presented a more catastrophic failure mode compared with the material with a higher filler content. Fractographic analysis revealed characteristic fracture patterns and failure-specific features. Higher predictability and greater fracture strength were observed for the low-filled material, as indicated by the Weibull analysis.
Polyimide membranes are generally limited by the permeability–selectivity trade-off during gas separation, which significantly restricts their further development and practical applications. Carbon molecular sieve membranes derived from polyimide (PI) precursors via pyrolysis have attracted considerable attention due to their excellent molecular sieving capability. In this study, polyaniline (PANI) was introduced to modify the polyimide matrix, and a series of PI/PANI precursor membranes with different PANI loadings were fabricated, followed by pyrolysis to obtain the corresponding CMS/PANI membranes. The effects of PANI incorporation on the structural evolution and gas separation performance of the membranes were systematically investigated. The results demonstrated that PANI incorporation effectively increased the fractional free volume (FFV) of the precursor membranes and promoted the formation of microporous structures during pyrolysis, resulting in enhanced BET surface area and a more developed microporous network in CMS/PANI membranes. Compared with the pristine PI-derived CMS membrane, CMS/PANI membranes exhibited significantly improved gas permeability while maintaining comparable gas pair selectivity. Among the prepared membranes, CMS/PANI-20 achieved the optimal overall separation performance, with H2 and CO2 permeabilities of 2012 and 754 Barrer, respectively, and H2/CH4 and CO2/CH4 selectivities of 253 and 95, respectively, exceeding the corresponding Robeson upper bounds.
