Search Results (408)

This study investigated the degradation behavior of a polyurethane acrylate coating/Q345B steel system under the coastal atmospheric conditions of Wenchang, Hainan, and evaluated the correlation between indoor accelerated tests and outdoor exposure. Outdoor exposure tests, single-factor accelerated tests (UV irradiation and neutral salt spray), and a multi-factor cyclic accelerated test combining UV, salt spray, humidity, and thermal cycling were conducted. Coating degradation was characterized by morphological observation, gloss measurement, adhesion testing, and electrochemical impedance spectroscopy. The results showed that after 8 months of outdoor exposure, localized rust spots, blistering, and under-film corrosion appeared on the coating surface. The gloss loss rate reached 15.72% after 3 months, while adhesion decreased from 5.83 MPa to 2.39 MPa during prolonged exposure. UV irradiation mainly affected gloss degradation, whereas corrosive media penetration played a dominant role in adhesion loss and electrochemical deterioration. Compared with single-factor tests, the multi-factor cyclic accelerated test exhibited the highest correlation with outdoor exposure. The corresponding correlation coefficients for gloss loss, adhesion, and low-frequency impedance modulus were 0.9764, 0.9988, and 0.9929, respectively, while the gray relational coefficients reached 0.8334, 0.8467, and 0.7977. These results demonstrate that the multi-factor cyclic accelerated test more accurately reproduces the degradation behavior and failure characteristics observed in the coastal atmosphere of Hainan. The proposed method provides a practical approach for indoor–outdoor correlation analysis and durability evaluation of protective coatings in marine atmospheric environments. Full article

The transition toward sustainable food packaging requires the integration of biodegradable materials with functional bioactivity. Chlorogenic acid (CGA), a naturally abundant polyphenol, has emerged as a multifunctional compound with the capacity to simultaneously modulate polymer structure and impart active and intelligent functionalities. This review critically examines recent advances in CGA-containing packaging systems, covering fabrication strategies from physical incorporation and chemical grafting to nanostructured and stimuli-responsive architectures. The analysis reveals that CGA plays a dual role. At the molecular level, it regulates the polymer network structure through hydrogen bonding, covalent interactions, and conformational rearrangement. This, in turn, influences mechanical strength, barrier performance, and optical properties. Functionally, CGA provides antioxidant and antimicrobial activity, although its effectiveness depends strongly on the incorporation strategy and concentration. Notably, nanostructured systems and conjugation approaches enable controlled release and enhanced stability. These methods overcome limitations associated with rapid diffusion and environmental degradation, including oxidation, UV exposure, and pH-related instability. Despite these advances, key challenges remain, including CGA instability, uncontrolled release behavior, and limited regulatory and scalability data. Furthermore, while CGA is well established in active packaging, its application in intelligent systems remains limited in the literature, with only a few studies reported on its intelligent applications. Overall, this review highlights the structure–function relationships governing CGA-containing packaging systems and outlines future directions for the rational design of cost-effective, scalable, and multifunctional packaging systems, positioning CGA as a promising component in sustainable strategies for food preservation and waste reduction. Full article

A conformal SiNx coating on carbon nanotubes (CNTs) was achieved by combining transient UV–ozone surface functionalization with a two-step atomic layer deposition (ALD) process. UV–ozone treatment gradually increased the defect density of CNTs, with the I_D/I_G ratio increasing from 0.05 for pristine CNTs to 0.25 after 7 min of exposure, while the overall fibrous CNT network remained intact. However, prolonged UV–ozone exposure beyond 10 min led to a sharp increase in the I_D/I_G ratio to 0.46, accompanied by structural degradation of the CNT membrane. Hydroxyl (-OH), epoxy (C-O-C), and carbonyl (C=O) groups were introduced by UV–ozone treatment and were partially removed during subsequent high-temperature processing. Accordingly, direct high-temperature ALD resulted in incomplete SiNx coverage of the CNTs, suggesting insufficient nucleation. A two-step ALD process, consisting of several cycles of low-temperature nucleation at 100 °C followed by high-temperature growth at 700 °C, enabled more conformal deposition of SiNx on CNTs. In addition, both annealing and ALD reduced the defect level toward that of pristine CNTs, supporting the transient nature of UV–ozone-induced functionalization. Full article

Ageing radically alters the physicochemical properties of microplastics, significantly increasing their affinity for environmental pollutants. However, the slow nature of natural degradation necessitates the development of efficient laboratory protocols. This study establishes an accelerated ageing methodology that reflects natural dynamics by comparing Polyethene terephthalate microplastics (PET MPs) exposed to sunlight (3 months) with those exposed to laboratory UV-C radiation (varying lamp numbers and 24–336 h). scanning electron microscopy (SEM) imaging confirmed progressive surface degradation, including increased roughness, micro-cavities, and erosion. Photo-oxidation was evidenced by an increase in the carbonyl index (CI) from 7.43 ± 0.30 to 8.97 ± 0.35 (UV-aged) and 11.45 ± 0.45 (sun-aged). Furthermore, crystallinity significantly decreased from 59.5% to 54.4% and 16.6%, respectively, while the point of zero charge (pH_PZC) shifted from near neutral (6.5–7.0) to below 2.0. Notably, high-intensity, short-term UV-C exposure accelerated surface functionalization, enhancing cadmium adsorption capacity (q_e = 1.9 mg/g). The laboratory protocol provides rapid reactivation on the surface, serving as a proxy for prolonged sunlight exposure. Consequently, these findings offer a framework for assessing heavy metal uptake and the broader environmental implications of microplastics in aquatic environments. This understanding supports pollutant evaluation and sustainable water management for aquatic ecosystem protection. Full article

The long-term exposure of asphalt pavement to ultraviolet radiation causes significant performance degradation and reduces its service life. To enhance the UV resistance of asphalt, nanocomposite modifiers have been incorporated through mechanical blending. However, their effectiveness has been largely limited by poor component uniformity. To address this issue, UV-resistant antioxidant nano-TiO₂ was employed to modify the UV-shielding of layered porous carbon (PC), resulting in the synthesis of nano-TiO₂ intercalated PC (TiO₂/PC). The PC nanosheet was modified by TiO₂ nanoparticles via in situ growth, significantly improving the dispersion homogeneity of TiO₂. Comprehensive characterization (SEM/EDS/FT-IR/XPS) confirmed the successful synthesis of TiO₂/PC with well-defined interfacial bonding. Compared to control samples (PC, TiO₂, and TiO₂ + PC), the asphalt modified by TiO₂/PC-2 composite demonstrated superior UV aging resistance, lower physical aging indices and reduced rheological aging parameters. Moreover, TiO₂/PC modifier prominently suppressed the formation of oxidative groups (C=O/S=O), improved the colloidal stability, and delayed the sol–gel transition of the modified asphalt. The synergistic UV shielding mechanism was attributed to the enhanced UV absorption of TiO₂, multi-reflection and scattering within the PC matrix, and the radical scavenging capabilities of both components. These results provide new design insights for developing anti-UV aging modifiers for asphalt pavements. Full article

The flotation performance of a low-grade, polymetallic copper ore, dominated by chalcocite and transitional copper phases, was investigated to assess the interplay between collector chemistry, gangue mineralogy, and entrainment. QEMSCAN analysis identified chalcocite as the main copper host (62%), with minor covellite and bornite, and gangue, predominantly quartz (94%), with variable muscovite (up to 50%). Chalcocite was moderately liberated (100–200 µm), while secondary copper phases showed low exposure and strong gangue association, challenging selective recovery. Baseline flotation with potassium amyl xanthate (PAX) and sodium isobutyl xanthate (SIBX) across pH and dosage ranges showed that PAX yielded higher copper recovery but lower grade, indicating unselective gangue entrainment; SIBX offered lower recovery but higher grade, reflecting superior selectivity. Controlled muscovite doping experiments (10–50 wt.%) were employed to decouple gangue-driven selectivity loss from collector-specific interactions. Results indicate a collector-dependent sensitivity to gangue loading: PAX exhibited a pronounced decline in both copper recovery (82%–67%) and grade under increasing muscovite content, with water recovery rising by approximately 32%, whereas SIBX showed more gradual performance degradation and lower entrainment (15% increase in water recovery), highlighting its resilience in gangue-rich systems. UV-Vis and zeta potential (electrokinetic) measurements confirmed stronger PAX adsorption, consistent with its longer hydrocarbon chain, while flotation trends demonstrated a shift from true flotation-dominated recovery to entrainment-dominated regimes at high muscovite levels, particularly for PAX. This framework links mineralogy, collector chemistry, and gangue entrainment, guiding optimization of circuits for ores like Mt. Gunson while enhancing critical metal recovery, including cobalt. Full article

This work analyses the influence of hydrothermal treatment (steaming) on the color stability and photochemical degradation of beech wood (Fagus sylvatica L.) with false heartwood under the influence of UV radiation. Samples in the native state and after steaming at temperatures of 105 °C (Mode I) and 120 °C (Mode II) were exposed to simulated aging in a Xenotest device for 360 h. Color changes were assessed in the color space CIE L*a*b* and surface chemical changes using ATR-FTIR spectroscopy. The results showed that unsteamed wood darkens significantly under the influence of UV radiation (ΔL* = −10.2), while wood steamed at 120 °C shows the opposite trend—lightening (ΔL* = +8.8). The color difference ΔE* reached values of 12 to 16 units for unsteamed wood, which indicates a complete color change. Steaming at higher temperatures successfully homogenizes the color of the sapwood and false heartwood and ensures their subsequent uniform visual aging. Full article

This study investigates the femtosecond laser surface texturing approach to tune the wetting properties of glass substrates applied for photovoltaic panels. Two types of microstructured LIPSS-containing motifs—parallel channels and intersecting (crossing) patterns—were fabricated and evaluated through comprehensive durability tests, including thermal cycling, UV exposure, chemical immersion, mechanical abrasion, and dust retention assessment. Wettability measurements showed that both textures exhibit stable hydrophilicity behavior, with the intersecting patterns exhibiting the fastest wetting dynamics; in many cases, complete surface wetting occurred within the first few minutes, preventing a measurable contact angle at later stages. The durability tests caused only minor smoothing of the textured features, and the overall micro- and nanostructures remained intact. Optical characterization revealed that the laser-induced textures maintained high transmittance with no significant degradation after environmental exposure. Overall, the results demonstrate that femtosecond laser texturing provides a robust, coating-free method for producing stable and tunable wetting behavior on glass, offering a promising pathway for the future creation of durable, highly hydrophilic self-cleaning surfaces in photovoltaic systems. Full article

Shot-hole disease caused by Wilsonomyces carpophilus poses a significant threat to stone fruit species, including wild apricot (Prunus armeniaca L.). This study investigated pathogenic factors (cell wall-degrading enzymes and toxins) and metabolites produced by a highly pathogenic strain (CFCC 71544) and a weakly pathogenic strain (CFCC 71543) of W. carpophilus during infection of P. armeniaca (in planta conditions). Analysis using the 3,5-dinitrosalicylic acid colorimetric method revealed that polygalacturonase (CFCC 71544: 1367.02 U/g; CFCC 71543: 1264.00 U/g) and polymethylgalacturonase (CFCC 71544: 1898.71 U·g⁻¹; CFCC 71543: 1762.21 U·g⁻¹) were the most active cell wall-degrading enzymes, with higher activities observed in the highly pathogenic strain (CFCC 71544). Crude toxins from CFCC 71543 induced leaf lesions averaging 41.91 mm² and retained activity after exposure to 121 °C and UV treatment. Non-protein fractions of the toxins caused significantly larger lesions than protein fractions (15.93 mm² vs. 5.56 mm², respectively). Building on these in planta findings, we further characterized toxin properties under controlled laboratory conditions (in vitro). Optimal toxin production conditions were identified in Richard culture medium at pH 4, under a 12 h light/dark cycle, shaken for 12 days at 25 °C. Untargeted metabolomics identified 3244 compounds and 977 differential metabolites among mycelia, crude toxins, and the residual aqueous phase after organic solvent extraction; these metabolites were predominantly amino acids and derivatives and organic acids. These findings indicate that the main pathogenic factors of W. carpophilus are highly active polygalacturonase and heat/UV-stable, water-soluble, non-protein toxins, providing a theoretical basis for shot-hole disease prevention and control. Full article

Perovskite solar cells (PSCs) have quickly achieved certified energy conversion efficiency reaching a certified record of 27.3% for single-junction cells, while having a low mass, thin-film form factor and high specific power, which are attractive for space energy systems. However, their long-term reliability in extraterrestrial environments is not adequately ensured by terrestrial qualification routes, and standardized space-related test protocols remain insufficiently developed. This review critically summarizes the current understanding of the degradation of PSCs under the influence of key environmental factors in space—ionizing and non-ionizing radiation, thermal vacuum exposure and thermal cycling, and ultraviolet radiation AM0, as well as atmospheric oxygen in low orbits. The central task of the work is to develop and justify the need to create specialized PSCs test protocols for space applications, since existing ground standards do not reflect the multifactorial nature and extreme orbital loads. It has been shown that thermal vacuum accelerates ion migration, interphase reactions, and degassing, while AM0 UV and atomic oxygen introduce additional photochemical and oxidative mechanisms of destruction; at the same time, stressors often act synergistically and are not detected by single-factor tests. Next, the limitations of the current IEC and ISOS are discussed and an approach to their expansion is formulated through the ISOS-T-Space and ISOS-LC-Space protocols, which integrate high vacuum, AM0 lighting, extended temperature ranges and controlled particle irradiation. It is concluded that the development and interlaboratory validation of such space-oriented protocols is a key condition for the correct qualification of PSCs and targeted optimization of materials and interfaces to meet the requirements of space energy. Full article

In an accelerated aging experiment involving a wide range of cumulative UV-B radiant exposures (up to approximately 9.46 × 10³ J cm⁻²), the degradation state of microplastics was assessed using SEM, FTIR, Raman spectroscopy, and DSC, and correlated with the cumulative UV-B dose. Sunlight-induced photooxidation is a significant weathering mechanism for microplastics. In this study, high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polyvinyl chloride (PVC), nylon, and polystyrene (PS) were exposed to UV-B radiation under controlled dry conditions at two irradiance levels (0.06 and 0.6 mW cm⁻²), covering cumulative UV-B radiant exposures of up to approximately 9.47 × 10³ J cm⁻². Degradation was evaluated using SEM, FTIR, Raman spectroscopy, and DSC, and was related to the cumulative UV-B dose (H). The extent and progression of degradation varied significantly among the polymers. Overall, FTIR provided the most sensitive assessment of photooxidative surface changes for HDPE, LDPE, PP, and PS, Raman spectroscopy was most diagnostic for PVC (particularly for dechlorination-related changes), and DSC-derived crystallinity was most informative for nylon. These dose-resolved datasets establish a reproducible reference framework (“degradation library”) to facilitate the comparative assessment of the relative photooxidative aging stage of microplastics under comparable surface UV-driven conditions. Outdoor “sunlight-equivalent” times are reported solely as order-of-magnitude contextualization due to environmental variability. Full article

This study reports the synthesis and evaluation of diclofenac-derived organotin(IV) complexes as photostabilizing additives for poly(vinyl chloride) (PVC). Diclofenac was selected as a ligand due to its aromatic structure and heteroatom-rich framework, enabling the formation of stable tin-based complexes with potential UV-absorbing and radical-scavenging properties. The synthesized di- and tri-organotin complexes were incorporated into PVC films at 0.5 wt.% and exposed to UV irradiation (365 nm) for up to 300 h to assess their stabilizing efficiency. Photodegradation was monitored by tracking changes in carbonyl, polyene, and hydroxyl indices, as well as weight loss and surface deterioration. Compared with blank PVC and ligand-containing films, the organotin-modified samples exhibited significantly slower growth of degradation indices, reduced mass loss, and improved surface integrity after irradiation. Among the evaluated additives, the tributyltin complex demonstrated the highest photostabilizing performance, showing superior retention of chlorine content and lower surface roughness parameters. Overall, the results indicate that diclofenac-based organotin(IV) complexes are effective photostabilizers for PVC, with the tributyltin derivative emerging as the most promising candidate for enhancing the durability of PVC materials under UV exposure. Full article

Effluents from industries, manufacturing companies, textile looms, and floodwater contaminate the surface water reservoirs. This endangers the quality of water for use by humans. Wastewater remediation is one of the ways to recycle the dirty water and make it suitable for use. Photocatalysis is the most common method for wastewater remediation, especially using Titanium dioxide (TiO₂) nanoparticles. However, chemical synthesis and direct addition of nanoparticles may cause toxicity to the flora and fauna present in the water body. To address this limitation, we have green-synthesized TiO₂ nanoparticles using a horticulture waste, Calendula officinalis dried flower extract and entrapped them in a natural polymer, chitosan (CTS-TiO₂-CO nanocomposite). The polymer entrapment ensures biocompatibility as well as reduced aggregation of nanoparticles. The synthesized CTS-TiO₂-CO nanocomposite was characterized using UV-visible spectrophotometry, dynamic light scattering, zeta potential, Fourier Transformed Infrared Spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX) analysis. The absorption peak was found at 302 nm, and the hydrodynamic diameter at 490 nm. SEM images show flower-like morphology with 326 nm average particle diameter. The non-toxic dose of the nanoparticles was estimated by MTT assay and zebrafish embryo developmental studies. More than 82% fibroblast cells were viable after treatment with 100 μg/mL of CTS-TiO₂-CO nanocomposite. 85% embryos hatched after treatment with 50 μg/mL of CTS-TiO₂-CO nanocomposite. Further, the textile dye remediation assessment was done using the dye crystal violet, exhibiting 69.19% dye degradation after 4 h of sunlight exposure. Altogether, the results demonstrate that the CTS-TiO₂-CO nanocomposite was effective in the remediation of crystal violet without causing any toxicity up to a dose of 100 μg/mL. Full article

The growing pollution caused by plastics with slow degradation kinetics is demanding the search for biodegradable alternatives. Starch-based films are a promising option, but their practical application may be limited by their potential susceptibility to rapid ultraviolet (UV) exposure degradation. This study evaluates the effect of prolonged UV-C irradiation (254 nm, 168 h) on plasticizer-free films derived from the starch of an Ecuadorian potato Solanum tuberosum (Chola variety). Films formulated at 3% and 5% (w/v) starch were characterized before and after UV exposure. The analysis includes the evaluation of optical, mechanical, and physicochemical properties, along with Fourier Transform Infrared spectroscopy (FTIR) and atomic force microscopy (AFM) for nanoscale surface inspection. UV irradiation increased the opacity of the films but reduced slightly their tensile strength, elongation at break, moisture content, and total soluble matter. In contrast, the elastic modulus remained relatively high. FTIR analysis revealed no significant formation of new functional groups. AFM measurements indicated that irradiation caused only minor nanoscale alterations in the same film regions. These alterations were more pronounced in films with higher starch concentrations. The results demonstrate that UV-C exposure induces minor structural adjustments in plasticizer-free starch films derived from the Chola variety, without compromising their fundamental integrity. Consequently, this work advances the understanding of the environmental stability of these films and supports their potential application as sustainable materials, even in conditions involving UV exposure. Full article

Ultraviolet (UV) exposure accelerates skin aging by inducing oxidative stress, extracellular matrix (ECM) degradation, and epidermal barrier dysfunction. This study investigated the protective effects of Brazilian pepper tree (SB), neem (SD), and Vietnamese coriander (PP) leaf extracts obtained by supercritical fluid extraction (SFE) using CO₂ with ethanol as a co-solvent against radiation-induced cellular damage. Among these, SB yielded the greatest amount of extract and exhibited the highest levels of phenolic and flavonoid constituents, including naringin, epicatechin gallate, and rosmarinic acid. These compounds, identified through HPLC profiling, were associated with strong inhibition of collagenase, elastase, and hyaluronidase, and exhibited potent antioxidant activity in the DPPH assay. Under UVC-induced oxidative stress in HaCaT keratinocytes, SB markedly enhanced the mRNA expression of key genes involved in ECM integrity (COL1A1, 3.04 ± 0.15-fold), epidermal barrier and hydration (FLG, 4.66 ± 0.17-fold; HAS1, 1.90 ± 0.14-fold), and cellular defense mechanisms (SIRT1, 3.83 ± 0.54-fold), demonstrating superior efficacy to reference antioxidants (EGCG and ascorbic acid) in upregulating key barrier genes like FLG. Overall, the findings highlight SB as the extract with the most comprehensive photoprotective properties and support the use of SFE-derived botanical extracts as promising agents for natural and photoprotective skincare applications. Full article