Search Results (64)

Recently, increased global awareness of environmental sustainability and ethical consumerism has amplified the demand for sustainable alternatives to animal-derived leather. Traditional leather manufacturing faces significant ethical and ecological challenges, including greenhouse gas emissions, excessive water consumption, deforestation, and toxic chemical usage. Vegan leather has emerged as a promising solution, predominantly fabricated from petroleum-based synthetic materials such as polyurethane (PU) and polyvinyl chloride (PVC). However, these materials have sustainability limitations due to their non-biodegradability and associated environmental burdens. To overcome these issues, this review critically explores the feasibility of developing vegan leather using gel-based materials derived from natural and synthetic polymers. These materials offer precise structural controllability, excellent biodegradability, and the potential for significantly improved mechanical performance through hybridization and nanocomposite strategies. Despite their promising attributes, gel-based materials face significant limitations, including insufficient tensile strength, poor abrasion resistance, susceptibility to swelling, limited long-term stability, and challenges in scaling up for industrial production. This paper outlines the structural and physical properties required for viable leather substitutes, reviews opportunities provided by gel-based materials, addresses associated technical challenges, and proposes comprehensive strategies for enhancing mechanical properties and developing sustainable, eco-friendly production processes. Future research directions emphasize hybrid composite development, nanoparticle integration, circular manufacturing processes, and multi-disciplinary collaboration to establish gel-based vegan leather as a viable, sustainable, and market-competitive alternative to conventional animal leather. Full article

This study addresses the critical challenge of precise control over active abrasive particles in magnetorheological polishing (MRP) through innovative core–shell particle engineering. A sol–gel synthesized CIP@SiO₂ magnetic composite abrasive with controlled SiO₂ encapsulation (20 nm shell thickness) was developed using tetraethyl orthosilicate (TEOS) as the silicon precursor, demonstrating significant advantages in optical-grade fused silica finishing. Systematic polishing experiments reveal that the core–shell architecture achieves a remarkable 20.16% improvement in surface quality (Ra = 1.03 nm) compared to conventional CIP/SiO₂ mixed abrasives, with notably reduced surface defects despite a modest 8–12% decrease in material removal rate. Through synergistic analysis combining elastic microcontact mechanics modeling and molecular dynamics simulations, we establish that the SiO₂ shell mediates stress distribution at tool–workpiece interfaces, effectively suppressing deep subsurface damage while maintaining nano-scale material removal efficiency. The time-dependent performance analysis further demonstrates that extended polishing durations with CIP@SiO₂ composites progressively eliminate mid-spatial frequency errors without introducing new surface artifacts. These findings provide fundamental insights into designed abrasive architectures for precision finishing applications requiring sub-nanometer surface integrity control. Full article

Diatomaceous earth (DE) consists of fossilized remnants of diatoms, which are marine or freshwater unicellular algae. Most DEs originate from fossilized sedimentary layers of diatoms deposited in water bodies during the Eocene and Miocene periods, much more than 20 million years ago. Processed DE, a soft, chalky powder, is widely used as an insecticide due to the highly absorptive and abrasive nature of its particles. As an insecticide, DE removes the wax coating of the insect epicuticle, the primary barrier against water loss. This results in water evaporation, leading to desiccation and death of the targeted insects. This review emphasizes the co-treatment of DEs with biological agents that have insecticidal properties (e.g., essential oils, plant powders, silica gel, and species/isolates of fungi), reducing the quantities used in single-application treatments and suggesting paths for the sustainable management of insects damaging stored products. Full article

Background: Postoperative adhesions are a common complication following abdominal surgery, affecting over 90% of patients and leading to significant morbidity. Current anti-adhesion strategies, such as the use of physical and chemical barriers, have limitations such as short retention time, mechanical fragility, and inefficient drug delivery. This study developed a pectin-based emulsion gel loaded with celecoxib to prevent adhesions and provide localized pain relief. Methods: Formulations (F1–F4) with different pectin concentrations were evaluated for rheological properties, mucoadhesion, degradation rate, and celecoxib release. In vivo efficacy was evaluated in Sprague−Dawley rats via a standardized model of peritoneal abrasion, in which the formulations were compared to a commercially available anti-adhesion barrier. Results: The optimized emulsion gel (F4) exhibited improved mucoadhesion (9009 mPa·s), prolonged retention, and controlled celecoxib release over 14 days, reaching 80% release by day 9. In vivo, formulation F4 significantly reduced adhesions compared to a commercially available product. Pharmacokinetic analysis showed rapid absorption (T_max = 2 h) and sustained celecoxib plasma levels, confirming its effectiveness as a localized drug-delivery system. The celecoxib-loaded pectin-based gel successfully prevented postoperative adhesions and provided sustained pain relief. Conclusions: These findings suggest its potential clinical utility, though further preclinical and clinical evaluations are required. Full article

Background: Although considerable data are available on oral venoactive drugs, very little information has been published on the types and outcomes of topical treatments for venous disease (VD). This comprehensive review assesses the efficacy and safety of topical heparin and heparinoid-containing products (HCPs) for VD treatment. Methods: This narrative review adhered to established methodologies and standards, utilizing the Scale for the Assessment of Narrative Review Articles (SANRA) for quality assessment. A comprehensive literature search was conducted across MEDLINE (PubMed), Scopus, and Web of Science, covering publications from January 1, 1950, to December 1, 2024. Findings were presented in a narrative format, following structured recommendations to ensure clarity and coherence. Results: Topical heparin and HCPs provide anticoagulation, enhance microcirculation, and regulate skin permeability, with effects influenced by the concentration and formulation. While they effectively improve skin microcirculation in healthy individuals, research on their intracellular effects is limited. Mucopolysaccharide polysulfate (MPS) in heparinoids offers similar vascular benefits and promotes antithrombotic and anti-inflammatory actions. Moisture and gentle abrasion enhance heparin absorption. Topical heparin and HCPs effectively treat superficial vein thrombosis (SVT) and varicose veins (VVs). Products like Hirudoid significantly alleviate SVT symptoms, including pain and swelling. Clinical trials demonstrate substantial symptom improvement with heparin gel (1000 IU/g). For varicose veins, Xioglican cream stabilizes symptoms and improves quality of life, while other formulations like Essaven Gel and Venoruton enhance microcirculation. Conclusions: Managing VD with topical treatments is complicated by the outdated literature and inconsistent methodologies. There is a clear need for systematic research to establish guidelines on the administration, dosage, and frequency of topical treatments. The recommendations in this review aim to provide a foundation for future studies to improve the management of SVT and VVs disease. Full article

Fumed silica, a nanomaterial with a high specific surface area, excellent chemical stability, and electrical insulation, serves as an effective filler for rubber compounding. Compared to traditional carbon black, silica (SiO₂), the main component of fumed silica, improves the hardness and tear resistance of tread rubber, making it a viable substitute in some formulations. However, silica-filled compounds generally exhibit lower tensile properties and abrasion resistance than carbon black. Fumed silica, with its higher structural integrity, provides additional reinforcement points within natural rubber matrices, enhancing tensile strength and abrasion resistance. Studies demonstrate that replacing carbon black with an equivalent amount of fumed silica as the primary filler significantly improves tread rubber’s hardness (by 20%) and 300% tensile modulus (by 14%) while also reducing rolling resistance and enhancing wet skid performance. Fumed silica’s large specific surface area and low density (10–15% of conventional silica) make it challenging to use directly as a tread rubber filler due to dust formation and prolonged mixing times. This study developed a process combining fumed silica with deionized water, followed by drying and ball milling. This treatment reduces the material’s volume, forming a cohesive gel that, upon processing, minimizes dust and significantly decreases mixing time and difficulty. The interaction between the hydroxyl (–OH) groups on the surface of fumed silica and water molecules likely results in hydrated silica. This interaction enhances surface polarity and forms a hydration layer, improving the hydrophilicity and dispersion of fumed silica in rubber matrices. This reduces the shear modulus difference (ΔG′) between low and high strain, maintaining a consistent elastic modulus over a wide strain range. Such stability enables rubber to perform better under dynamic loads or in complex working conditions. The experimental results demonstrate that the hydration–ball milling process enhances the tensile strength of vulcanizates, improves the dispersion of fumed silica in rubber, strengthens the filler network, boosts dynamic performance, and enhances the wet skid resistance of tread rubber. Full article

Newly developed Sol–gel (SG) flexible tools are used to polish complex marble surfaces with a robot to achieve a high-gloss, low-roughness, and scratch-free surface. The SG tool is composed of semi-solid abrasive and flexible fiber pads, which can realize a dual yielding effect at both the micro and macro levels so that the SG flexible tool can better fit the complex curved surface. Through the simulation analysis of the contact of SG flexible tools, the relationship between different curvature surfaces and polishing forces was obtained. Based on the Preston material removal theory, constant-pressure polishing of surfaces of different curvatures was achieved by simulating the contact force distribution between the SG flexible tool and the marble surface, as well as the constant-pressure material removal profile. By optimizing the space of the polishing trajectory, the uniformity of the material removal depth was improved, and the consistency of surface quality after polishing was enhanced. By establishing a model that correlates the optimum polishing trajectory space with curvature for surfaces of different curvatures, the effective prediction of material removal profiles for robotic polishing of surfaces of different curvatures was achieved. These strategies aim to ensure surface consistency after polishing complex curved surfaces under different conditions, thereby increasing the product’s added value. This research provides initial theoretical guidance for the application of SG flexible tools in the robotic polishing of marble with complex curved surfaces. Full article

To further enhance the abrasion resistance of UHPC in demanding abrasion environments, this study investigated the effects of graphene oxide (GO) on the workability, mechanical properties, and abrasion resistance of UHPC. Utilizing 27Al Nuclear Magnetic Resonance (NMR), 29Si NMR, microhardness, and BET analysis, the study analyzed the mechanisms through which GO influences UHPC’s microstructure in terms of abrasion resistance. Additionally, molecular dynamics simulations were employed to examine the mechanisms by which GO enhances UHPC’s abrasion resistance at the nano and micron scale. The findings show that an optimal amount of GO can improve the mechanical properties and abrasion resistance of UHPC. When 0.03% of GO (by cementitious material mass) was incorporated, the impact on workability was minimal, yet compressive strength increased by approximately 1.80%, flexural strength by 3.02%, impact wear resistance by 1.78%, the abrasion loss rate decreased by 10.01%, ultimate impact energy increased by 1.76%, and the toughness index improved by 10.10%. GO enhances abrasion-resistant UHPC primarily by increasing hydration, refining pore structure, and improving the microstructure of the interfacial transition zone. While GO increases the hydration degree of the UHPC matrix, it does not alter the silicate chain in C-A-S-H gels within the paste. Additionally, the incorporation of graphene oxide can refine the pore structure of the UHPC cement paste and improve the microstructure of the interfacial transition zone (ITZ) between the aggregate and the cement paste. The molecular dynamics simulation reveals that, under abrasive forces, GO forms strong, stable chemical bonds with the C-A-S-H base atoms, significantly enhancing the abrasion resistance of C-A-S-H. Full article

Aloe vera is well known for its biological properties as a bioflavonoid anti-inflammatory and antibacterial agent. It has been used frequently in the food sector as a food coating due to its hygroscopic properties and as an ingredient in the lucrative cosmetic industry. Studies have also included aloe vera as an eco-friendly green solution based on these properties. The current research focuses on the use of aloe vera gel in printing pastes as an alternative sustainable solution to synthetic thickeners, evaluating its wet performance and ease of fabric stitching, and has been inspired by studies that similarly used this substance and measured its effect on the fabric’s coefficient of friction and antimicrobial action. In the current study, printing pastes with natural colourants, such as saffron, curcumin, and annatto, and aloe vera gel thickener derived from natural leaves from Crete increased the fabric’s mechanical resistance to abrasion compared to the untreated pastes. The measured performance did not differ substantially from prints with traditional synthetic pastes, hence tolerating the substitution with the non-contaminant variant. The enhanced resistance to abrasion and wear extends the fabric’s serviceable life and resulting garments, decreasing the need for high industry processing volumes and, as a result, reducing pollution. The resistance to wear was evaluated using the dominant method in textile testing of the Martindale apparatus, which measured the cycles to failure, weight loss, and general appearance deterioration using the official photographic standards. Full article

In order to further enhance the erosion resistance of cement concrete pavement materials, this study constructed an apparent rough hydrophobic structure layer by spraying a micro-nano substrate coating on the surface layer of the cement concrete pavement. This was followed by a secondary spray of a hydroxy-silicone oil-modified epoxy resin and a low surface energy-modified substance paste, which combine to form a superhydrophobic coating. The hydrophobic mechanism of the coating was then analysed. Firstly, the effects of different types and ratios of micro-nano substrates on the apparent morphology and hydrophobic performance of the rough structure layer were explored through contact angle testing and scanning electron microscopy (SEM). Subsequently, Fourier transform infrared spectroscopy and permeation gel chromatography were employed to ascertain the optimal modification ratio, temperature, and reaction mechanism of hydroxy-silicone oil with E51 type epoxy resin. Additionally, the mechanical properties of the modified epoxy resin-low surface energy-modified substance paste were evaluated through tensile tests. Finally, the erosion resistance of the superhydrophobic coating was tested under a range of conditions, including acidic, alkaline, de-icer, UV ageing, freeze-thaw cycles and wet wheel wear. The results demonstrate that relying solely on the rough structure of the concrete surface makes it challenging to achieve superhydrophobic performance. A rough structure layer constructed with diamond micropowder and hydrophobic nano-silica is less prone to cracking and can form more “air chamber” structures on the surface, with better wear resistance and hydrophobic performance. The ring-opening reaction products that occur during the preparation of modified epoxy resin will severely affect its mechanical strength after curing. Controlling the reaction temperature and reactant ratio can effectively push the modification reaction of epoxy resin through dehydration condensation, which produces more grafted polymer. It is noteworthy that the grafted polymer content is positively correlated with the hydrophobicity of the modified epoxy resin. The superhydrophobic coating exhibited enhanced erosion resistance (based on hydrochloric acid), UV ageing resistance, abrasion resistance, and freeze-thaw damage resistance to de-icers by 19.41%, 18.36%, 43.17% and 87.47%, respectively, in comparison to the conventional silane-based surface treatment. Full article

In the field of high-end equipment, the synergistic effect of friction-reducing agents plays an important role in the performance study of gel grease. Exploring its tribological and rheological properties can not only significantly reduce the coefficient of friction of mechanical components and enhance its viscosity at high temperatures but also effectively reduce energy consumption, thus improving the service life of high-end equipment. In this study, Schaeffler Load 460 gel grease was mixed with polysiloxane viscosity modifier (PV611) and molybdenum dialkyl dithiocarbamate (RFM3000) according to (3:1, 1:1, and 1:3), and its tribological properties and rheological properties were investigated by the MRS-10G friction and wear tester, MCR302 rotational rheometer, and crossover test. Comparative analyses of tribological and rheological properties were carried out. The results showed that the average coefficient of friction of Schaeffler Load 460 grease was reduced by 57.2%, 60%, and 71.9%, respectively, with the addition of two different ratios of friction reducers; the average diameter of abrasive spots was reduced by 44.5%, 55.4%, and 61.3%; and the shear stress and viscosity were increased by 117.94 Pa and 1295.02 mPa∙s, respectively, compared with that of the original grease, which is a good example for the lubrication of gel grease in the high-end equipment industry. This study provides a new direction and idea for the lubrication research of gel grease in the high-end equipment industry. Full article

Background: In patients undergoing surgery for oral cancer, soft support materials are used to minimise trauma to the soft tissues. Silicone-based liners are widely used in prosthetic dentistry. A prerequisite for long-term Adhesion of the liner to the denture base is largely dependent on the surface preparation of the denture material. Objectives: The aim of the present study was to investigate whether surface preparation of the acrylic material by sandblasting increases the adhesion of the silicone support material to the acrylic denture plate. Material and Methods: The study included adhesion testing of four silicone-based soft cushioning materials (Silagum Comfort, Elite Soft Re-lining, Ufi Gel SC, Mucopren Soft) on a total of 270 samples. Each material was tested on 15 samples. Three subgroups with different surfaces were separated: 1 raw—standard surface treatment with a cutter, and 2 sandblasted, with 100 and 350 µm alumina grain at 90°. The samples were subjected to seasoning: 24 h and six weeks. The adhesion force of silicone to acrylic was measured by performing a tensile test using a universal two-column testing machine. Results: The highest bond strength was recorded for Silagum on the surface prepared using 100 µm abrasive and seasoned for 6 weeks (291.5 N). The smallest among the maximum forces was recorded for the Mucopren material (81.1 N). For the Mucopren system with a raw and sand-blasted surface (350 µm), the adhesion strength increased after six weeks. In contrast, the durability of the joint decreased for the 100 µm sandblasted surface. The Elite material exhibited similar values for maximum forces (271.8 N) and minimum forces (21.1 N). The highest strength (226.1 N) was recorded for the sample from the group prepared with 350 µm abrasive and seasoned for 24 h. The lowest value (72.6 N) occurred for the sample from the group with 100 µm abrasive and seasoned for 6 weeks. Conclusions: Sandblasting of acrylic plastic improves adhesion to selected relining silicones. 2. The size of the abrasive employed has an impact on the adhesion between the acrylic plastic and the bedding silicone. 3. In the case of some relining systems (Mucopren), an increase in roughness through sandblasting has the effect of reducing the durability of the bonded joint. Full article

The application of superamphiphobic coatings improves the surface’s ability to repel fluids, thereby greatly enhancing its various functions, including anti-fouling, anti-corrosion, anti-icing, anti-bacterial, and self-cleaning properties. This maximizes the material’s potential for industrial applications. This work utilized the agglomeration phenomenon exhibited by nano-spherical titanium dioxide (TiO₂) particles to fabricate 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) modified TiO₂ (TiO₂@fluoroPOS) fillers with low surface energy. This was achieved through the in-situ formation of protective armor on the surface of the agglomerates using the sol-gel method and fluorination modification. Polyvinylidene fluoride-tetrafluoropropylene (PVDF-HFP) and TiO₂@fluoroPOS fillers were combined using a spraying technique to prepare P/TiO₂@fluoroPOS coatings with superamphiphobicity. Relying on the abundance of papillae, micropores, and other tiny spaces on the surface, the coating can capture a stable air film and reject a variety of liquids. When the coatings were immersed in solutions of 2 mol/L HCl, NaCl, and NaOH for a duration of 12 h, they retained their exceptional superamphiphobic properties. Owing to the combined influence of the armor structure and the organic binder, the coating exhibited good liquid repellency during water jetting and sandpaper abrasion tests. Furthermore, the coating has shown exceptional efficacy in terms of its ability to be anti-icing, anti-waxing, and self-cleaning. Full article

In silicon carbide processing, the surface and subsurface damage caused by fixed abrasive grinding significantly affects the allowance of the next polishing process. A novel grinding wheel with a soft and hard composite structure was fabricated for the ultra-precision processing of SiC substrates, and the grinding performance of the grinding wheel was assessed in this study. Different types of gels, heating temperatures, and composition ratios were used to fabricate the grinding wheel. The grinding performance of the grinding wheel was investigated based on the surface integrity and subsurface damage of SiC substrates. The results showed that the grinding wheel with a soft and hard composite structure was successfully fabricated using freeze-dried gel with a heating temperature of 110 °C, and the component ratio of resin to gel was 4:6. A smooth SiC substrate surface with almost no cracks was obtained after processing with the grinding wheel. The abrasive exposure height was controlled by manipulating the type and ratio of the gel. Furthermore, the cutting depth in nanoscale could be achieved by controlling the abrasive exposure height. Therefore, the fabrication and application of the grinding wheels with soft and hard composite structures is important for the ultra-precision processing of large-size SiC substrates. Full article

The aim of this study is to analyze the effect of the addition of TiO₂ nanoparticles (NTs) on the physical and mechanical properties, as well as the microstructural changes, of cementitious composites containing partially substituted natural aggregates (NAs) with aggregates derived from the following four recycled materials: glass (RGA), brick (RGB), blast-furnace slag (GBA), and recycled textolite waste with WEEE (waste from electrical and electronic equipment) as the primary source (RTA), in line with sustainable construction practices. The research methodology included the following phases: selection and characterization of raw materials, formulation design, experimental preparation and testing of specimens using standardized methods specific to cementitious composite mortars (including determination of apparent density in the hardened state, mechanical strength in compression, flexure, and abrasion, and water absorption by capillarity), and structural analysis using specialized techniques (scanning electron microscopy (SEM) images and energy dispersive X-ray spectroscopy (EDS)). The analysis and interpretation of the results focused primarily on identifying the effects of NT addition on the composites. Results show a decrease in density resulting from replacing NAs with recycled aggregates, particularly in the case of RGB and RTA. Conversely, the introduction of TiO₂ nanoparticles resulted in a slight increase in density, ranging from 0.2% for RTA to 7.4% for samples containing NAs. Additionally, the introduction of TiO₂ contributes to improved compressive strength, especially in samples containing RTA, while flexural strength benefits from a 3–4% TiO₂ addition in all composites. The compressive strength ranged from 35.19 to 70.13 N/mm², while the flexural strength ranged from 8.4 to 10.47 N/mm². The abrasion loss varied between 2.4% and 5.71%, and the water absorption coefficient varied between 0.03 and 0.37 kg/m²m^0.5, the variations being influenced by both the nature of the aggregates and the amount of NTs added. Scanning electron microscopy (SEM) images and energy dispersive X-ray spectroscopy (EDS) analysis showed that TiO₂ nanoparticles are uniformly distributed in the cementitious composites, mainly forming CSH gel. TiO₂ nanoparticles act as nucleating agents during early hydration, as confirmed by EDS spectra after curing. Full article