Search Results (1,553)

This study examines the swelling behaviour of nitrile-butadiene rubber (NBR) when interacting with tyre pyrolysis oils (TPO), with a focus on the chemical composition of TPO and their interaction with rubber matrices. Initially, a comparative analysis with conventional diesel fuel (DF) was performed using advanced analytical techniques, including two-dimensional gas chromatography coupled to mass spectrometry (2D-GC/MS), infrared (IR) spectroscopy, and nuclear magnetic resonance (¹H-NMR) spectroscopy. The analysis revealed that TPO contains a significantly higher proportion of aromatic hydrocarbons than DF, along with unsaturated and oxygen-containing compounds not present in DF. Based on these compositional differences, blends of TPO and DF were formulated and evaluated for their suitability as liquid energy carriers according to the specifications of DF. In principle, blends with an addition of up to 5 vol% TPO in DF are technically suitable for use as fuel. Subsequently, the sorption behaviour of TPO, DF, and their blends in NBR was investigated. The swelling potential was determined based on mass, density, and volume, and the changes in the hardness and tensile strength of NBR were recorded. The results demonstrate that TPO induces pronounced swelling in NBR, as evidenced by a marked increase in mass uptake and volume expansion. A linear increase was observed between the degree of swelling and the increasing TPO content in the blends. Mechanical property assessments revealed a corresponding decrease in the hardness and tensile strength of NBR upon exposure to TPO, with the most severe effects associated with neat TPO. This work provides a comprehensive assessment of TPO as a potential blend component for DF. It highlights the need for careful consideration of material compatibility in practical applications. Full article

This article evaluates the influence of replicated natural structures, produced by micro-machining, on the wettability of plastic parts made from hydrophilic and hydrophobic polymer materials under various temperature and pressure conditions. Although many studies have focused on biomimetic surface design, the effect of specific processing parameters on the accurate replication of natural topologies and their resulting wettability has been only partially explored. This study addresses this gap by systematically analyzing the effect of melt temperature and packing pressure on the functional replication of micro-machined biomimetic structures. The research describes the design of hierarchical microstructures inspired by biomimetics and their fabrication by micro-milling on molded parts. Test samples were prepared from polypropylene (PP), acrylonitrile butadiene styrene (ABS), and polyamide 6.6 (PA 6.6) under different processing parameters, and wettability was assessed using contact angle (CA) measurements. The results confirmed significant variations in surface wettability depending on polymer type, melt temperature, and packing pressure. For the hydrophilic relief (Rock Moss), contact angles below 90° were obtained for all tested polymers, including PP, which decreased from 98.7° on a flat surface to 82.4° at 220 °C and 500 bar. In PA 6.6, a reduction of up to 12% in contact angle was observed compared to smooth samples at 310 °C and 500 bar. For hydrophobic reliefs (Three-part Hibiscus and Tricolor Pansy), contact angles exceeded 100–110°, with the highest value of 108.3 ± 1.6° for PP at 200 °C and 500 bar. Suitable combinations of melt temperature and packing pressure enabled accurate replication of microstructures while preserving their functional wettability, demonstrating the possibility of tuning surface properties through topological design. Full article

Reactions of anhydrous Zn(II) iodides with redox-active 1,4-diaza-1,3-butadiene (DAD) and its bis(imino)acenaphtene (BIAN) derivatives in absolute acetonitrile yielded a series of new complexes: [(Mes-DAD)ZnI₂] (1), [(dpp-DAD)ZnI₂] (2), and [(dpp-BIAN)ZnI₂] (3). Single crystals of all compounds were obtained, and their molecular structures were unambiguously determined by X-ray diffraction analysis. Purity of bulk samples in solid state was confirmed by PXRD. Stability of the complexes in solution was investigated by means of UV-Vis and NMR spectroscopy. Cyclic voltammetry revealed two or three quasi-reversible reduction waves in the cathodic region for complexes 1–3. The ability of 3 to accept up to three electrons highlights the potential of these compounds as electrocatalysts for reductive transformations. Full article

The current global economic challenges and resource scarcity necessitate the development of cost-effective and sustainable pavement solutions. This study investigates the performance of asphalt mixtures modified with Low-Density Polyethylene (LDPE) and Styrene–Butadiene–Styrene (SBS) as binder modifiers, and Hydrated Lime (Ca(OH)₂) and Reclaimed Asphalt Pavement (RAP) as aggregate replacements. The research aims to optimize the combination of these materials for enhancing the durability, sustainability, and mechanical properties of asphalt mixtures under various climatic and traffic conditions. Asphalt mixtures were modified with 5% LDPE and 2–6% SBS (by bitumen weight), with 2% Hydrated Lime and 15% RAP added to the mix. The performance of these mixtures was evaluated using the Simple Performance Tester (SPT), focusing on rutting, cracking, and fatigue resistance at varying temperatures and loading frequencies. The NCHRP 09-29 Master Solver was employed to generate master curves for input into the AASHTOWare Mechanistic-Empirical Pavement Design Guide (MEPDG), allowing for an in-depth analysis of the modified mixes under different traffic and climatic conditions. Results indicated that the mix containing 5% LDPE, 2% SBS, 2% Hydrated Lime, and 15% RAP achieved the best performance, reducing rutting, fatigue cracking, and the International Roughness Index (IRI), and improving overall pavement durability. The combination of these modifiers showed enhanced moisture resistance, high-temperature rutting resistance, and improved dynamic modulus. Notably, the study revealed that in warm climates, thicker pavements with this optimal mix exhibited reduced permanent deformation and better fatigue resistance, while in cold climates, the inclusion of 2% SBS further improved the mix’s low-temperature performance. The findings suggest that the incorporation of LDPE, SBS, Hydrated Lime, and RAP offers a sustainable and cost-effective solution for improving the mechanical properties and lifespan of asphalt pavements. Full article

The slow swelling rate of styrene–butadiene–styrene (SBS) in asphalt prolongs the modification process and increases energy consumption. This study proposes a novel method using benzoyl peroxide (BPO) and benzoyl methane (BPA) to accelerate SBS swelling through a radical initiation–capture mechanism. BPO generates free radicals that relax the SBS network, while BPA captures excess radicals, maintaining system stability. Molecular dynamics simulations based on the COMPASS II force field were used to analyse diffusion, radius of gyration, and solubility parameters, revealing that BPO/BPA improved SBS–asphalt compatibility and increased the diffusion coefficient by 76%. Macroscopic viscosity tests confirmed that the swelling time decreased by 40% and equilibrium viscosity increased by 39% compared with the conventional process. The modified asphalt also exhibited enhanced high- and low-temperature performance and ageing resistance. This simple and efficient synergistic technique provides a promising approach for the rapid preparation of SBS-modified asphalt and offers practical potential for industrial production. Full article

Unexpected activation of the tetrabutylammonium cation in the presence of hexachloroplatinate(IV) under light to give a dinuclear complex of trans-μ²:η²,η²-1,3-butadiene-bis(trichloroplatinate(II)) along with a proposed mechanism of the activation has been reported. The mechanism has been investigated using a combination of photodissociation photodetachment mass spectrometry, and frozen-matrix EPR spectroscopy, in addition to 1D and 2D NMR spectroscopy. In addition to the Bu₄N⁺ salts of [PtCl₆]²⁻ that were part of the original observations, the reactivity of Bu₄P⁺, Pr₄N⁺, and Pe₄N⁺ (Pe = pentyl) salts has also been investigated, and, in addition, the possible involvement of η²-butene complex intermediates has been investigated. The combined results provide additional evidence and support for the originally proposed mechanism of activation of the Bu₄N⁺ cation. Full article

In injection molding, draft angle design plays a critical role in ensuring smooth de-molding and maintaining surface quality. With the growing emphasis on aesthetics and the increasing demand for the appearance of plastic products, the need for textured plastic components has continuously risen. The coupling between surface texture replication and dimensional accuracy has become an important indicator of product performance. However, systematic studies on the interaction between different polymer materials and draft angle design remain limited. This study aims to investigate the influence of draft angle variation on the surface texture quality and dimensional stability of injection-molded parts by comparing the differences between crystalline and amorphous thermoplastic materials, as well as between commodity and engineering plastics. Four representative polymers, namely polypropylene (PP), polyoxymethylene (POM), acrylonitrile-butadiene-styrene (ABS), and polycarbonate (PC), were selected to examine the impact of material characteristics on surface texture replication after molding. In addition, product geometries incorporating eight draft angles (0° to 3.5°) were designed. Surface texture replication was analyzed using scanning electron microscopy (SEM) and surface profilometry, while dimensional deformation was measured with a high-precision optical measuring instrument. The results show that draft angle variation has a limited influence on the overall trend of dimensional deformation, but it has a significant effect on the clarity of surface replication. Crystalline polymers exhibited generally higher surface roughness than amorphous polymers, and the distinction between commodity and engineering plastics, particularly those requiring higher processing temperatures, also led to higher roughness (PP > POM; ABS > PC). Dimensional deformation was more pronounced in crystalline polymers (POM > PP > ABS > PC). SEM observations further confirmed that higher roughness corresponded to clearer and more distinguishable texture patterns, whereas lower roughness resulted in blurred or indistinct textures. Full article

Nano- and microplastics (NMPs) in waterways reflect the impact of anthropogenic activities. This study examined spatial variations in the presence and types of NMPs in Galveston Bay (Texas, USA) surface waters and eastern oysters (Crassostrea virginica). The results reveal most MPs carried by surface waters are fibers > films > fragments. Up to 200 MPs were present in individual oysters [=1.88 (± 0.22 SE) per g wet weight]. Oyster health, based on condition index, varied spatially, but was not correlated with MP load. Based on attenuated total reflectance—Fourier-transform infrared spectroscopy, polyamide and polypropylene were frequently found in waters in the upper bay while ethylene propylene and polyethylene terephthalate were more common in the lower parts of the bay. Pyrolysis–gas chromatography–mass spectrometry revealed a very large range in concentrations of NMPs, from 28 to 10,925 µg ∑NMP/g wet weight (or 172 to 67,783 µg ∑NMP/g dry weight) in oysters. This chemical analysis revealed four main types of plastics present in oysters regardless of location: polypropylene, nylon 66, polyethylene and styrene butadiene rubber. Based on this finding, the average daily intake of NMPs estimated for adult humans is 0.85 ± 0.45 mg NMPs/Kg of body weight/day or a yearly intake of 310 ± 164 mg NMPs/Kg of body weight/year. These findings reveal higher body burdens of plastics in oysters are revealed by the chemical analysis relative to the traditional approach; this is not unexpected given the higher sensitivity and selectivity of mass spectrometry and inclusion of the nanoplastic particle range (i.e., <1 mm) in the sample preparation and analysis. Full article

In this study, the thermal and structural behavior of battery module components produced from polymer-based composites was systematically evaluated using coupled Moldflow 2016 and ANSYS Fluent 2024 simulations. Three thermoplastics—metal-flake-reinforced PC+ABS (Polycarbonate/Acrylonitrile Butadiene Styrene), carbon-fiber-reinforced PEEK (Polyether Ether Ketone), and hybrid mineral-filled PP (Polypropylene)—were investigated as alternatives to conventional aluminum components. Moldflow simulations enabled the assessment of injection molding performance by determining injection pressure, volumetric shrinkage, warpage, residual stress, flow front temperature, and part weight. PEEK exhibited the best dimensional stability, with minimal warpage and shrinkage, while PP showed significant thermomechanical distortion, indicating poor resistance to thermally induced deformation. For thermal management, steady-state simulations were performed on a 1P3S pouch cell battery configuration using the NTGK/DCIR model under a constant heat load of 190 W. Material properties, including temperature-dependent thermal conductivity, density, and specific heat capacity, were defined based on validated databases. The results revealed that temperature distribution and Joule heat generation were strongly influenced by thermal conductivity. While aluminum exhibited the most favorable thermal dissipation, PC+ABS closely matched its electrical performance, with only a 1.3% lower average current magnitude. In contrast, PEEK and PP generated higher cell core temperatures (up to 20 K) due to limited heat conduction, although they had comparable current magnitudes imposed by the energy-conserving model. Overall, the findings indicate that reinforced thermoplastics, particularly PC+ABS, can serve as lightweight and cost-effective alternatives to aluminum in mid-range battery modules, providing similar electrical performance and thermal losses within acceptable limits. Full article

Manganese complexes of the general formula [Mn(DAB)(CO)₃Br] featuring sterically demanding α-diimine ligands (DAB) were prepared, characterized, and found to be catalytically active in the hydroboration of ketones. The developed eco-friendly approach allowed straightforward formation of boronic esters in quantitative yields in mild and solvent-free conditions. Full article

Rubberized concrete is a novel green building material that enhances many features when rubber particles are incorporated into cement mortar, simultaneously yielding economic benefits through the recycling of waste tires. This study applies styrene–butadiene latex (SBL) for toughening treatment. The investigation delves into the mechanism by which SBL improves the interface between rubber and cement, encompassing macroscopic mechanical properties, microscopic structural characteristics, and nano-scale interfacial interactions. Macroscopic mechanical tests reveal a significant increase in flexural strength, shear strength, and compressive strength of the composite concrete upon the introduction of SBL and rubber. Specifically, the compressive strength improved by 8.8%, shear strength by 13.7%, and flexural strength by 18.9% at 28 days. Through electron microscopy observation of corresponding polymer cement concrete sections, observations reveal that SBL reinforces both interfaces and elucidates its bonding impact at the micro-level interface. Molecular dynamics (MD) modeling of SBL/rubber/CSH is employed at the nanoscale to compute and examine the local structure, dynamic behavior, and binding energy of the interface. The findings indicate that SBL mitigates interface impacts, enhances interface hydrogen bonds, van der Waals interactions, $\mathrm{C}\mathrm{a}-\mathrm{H}$ coordination bonds, and stability, consequently improving interfacial adhesion and fortifying the feeble interface bonding between organic polymers (rubber) and inorganic silicates (CSH). Full article

Additive manufacturing is driving a significant change in industry, extending beyond prototyping to the inclusion of printed parts in final designs. Stereolithography (SLA) is a polymerization technique valued for producing highly detailed parts with smooth surface finishes. This study presents a hybrid intelligent framework for modeling and optimizing the SLA 3D printer process’s parameters for Acrylonitrile Butadiene Styrene (ABS) photopolymer parts. The nonlinear relationships between the process’s parameters (Orientation, Lifting Speed, Lifting Distance, Exposure Time) and multiple performance characteristics (ultimate tensile strength, yield strength, modulus of elasticity, Shore D hardness, and surface roughness), which represent complex relationships, were investigated. A Taguchi design of the experiment with an L18 orthogonal array was employed as an efficient experimental design. A novel hybrid fuzzy logic–Particle Swarm Optimization (PSO) algorithm, ARGOS (Adaptive Rule Generation with Optimized Structure), was developed to automatically generate high-accuracy Mamdani-type fuzzy inference systems (FISs) from experimental data. The algorithm starts by customizing Modified Learn From Example (MLFE) to create an initial FIS. Subsequently, the generated FIS is tuned using PSO to develop and enhance predictive accuracy. The ARGOS models provided excellent performances, achieving correlation coefficients (R²) exceeding 0.9999 for all five output responses. Once the FISs were tuned, a multi-objective optimization was carried out based on the weighted sum method. This step helped to identify a well-balanced set of parameters that optimizes the key qualities of the printed parts, ensuring that the results are not just mathematically ideal, but also genuinely helpful for real-world manufacturing. The results showed that the proposed hybrid approach is a robust and highly accurate method for the modeling and multi-objective optimization of the SLA 3D process. Full article

The growing demand for sustainable solutions in the plastics industry has highlighted the need to reintroduce post-industrial polymer waste into high-performance applications. This study focuses on the mechanical recycling of automotive scraps containing variable proportions of polycarbonate (PC), acrylonitrile–butadiene–styrene (ABS), and a commercial PC/ABS blend. After determining the composition of two representative batches, a screening of seven commercial compatibilizers and impact modifiers was performed to improve impact strength. Among them, an ethylene–methyl acrylate–glycidyl methacrylate (E-MA-GMA) terpolymer was identified as the most effective additive. Its influence was further investigated through a mixture design approach, varying the composition of the three polymer phases and the additive content (0–10 wt.%). The resulting response surface model revealed a significant increase in impact resistance in PC-rich formulations with increasing E-MA-GMA content, while ABS and PC/ABS showed more complex trends. Rheological, mechanical, and thermal analyses supported the observed behavior, suggesting improved matrix compatibility and reduced degradation during processing. The proposed model enables the prediction of impact performance across a wide range of compositions, offering a practical tool for the optimization of recycled blends. These findings support the potential of targeted compatibilization strategies for closed-loop recycling in the automotive sector. Full article

Plastic recycling has been a challenge worldwide due to various reasons, including limited profit margins, the demand for high-quality plastic reprocessing techniques to make products comparable to those from virgin materials, and challenges in sorting and processing. This problem became particularly urgent in the small towns in the U.S., where plastic waste was shipped overseas for treatment, but now it is not accepted in some countries. This study aims to understand the plastic value chain and find the necessary factors for a circular economy model of both environmental and economic settings. In this study, an educational plastics reprocessing workspace was developed with manufacturing processes such as shredding, filament extruding, 3D printing, and injection molding. A series of products was developed to increase the value of the recycled polymers. In addition, quality control of recycled polymers such as polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), polyethylene terephthalate (PET), and polyethylene terephthalate glycol (PETG) was examined. By collaborating with a university manufacturing lab, this work illustrates how plastics can be collected, prepared, and reprocessed, serving as a platform for student learning and community outreach. This study contributes to the body of knowledge by presenting a case-based educational model for community-level plastic recycling and reprocessing in a college town context. Full article

In this study, a surface texture design technique for 3D-extruded prototype products was developed. The study determines some target functional properties of polymer-made items. Four series of experimental samples (acrylonitrile–butadiene–styrene (ABS), thermoplastic polyurethane (TPU), polylactide (PLA), and polyethylene terephthalate glycol (PETG)) were 3D-printed using the fused filament fabrication (FFF) approach. The morphology and hydrophilic/hydrophobic balance of the surfaces of the experimental samples were regulated directly by the 3D design and by gas-phase fluorination techniques. The observed distilled water and ethylene glycol edge wetting angles of the surfaces of the experimental samples were determined by a 3D filament stroke arrangement. It was shown that varying the 3D design promoted hydrophobization and provided anisotropic wetting (the distilled water edge angle of the same sample varies from 76 to 116 degrees). The textured surfaces simultaneously demonstrated hydrophilicity in one direction and hydrophobicity in the other. The changing of the fluorine-containing gas mixture surface treatment duration allowed us to alter the hydrophilic/hydrophobic balance of 3D-extruded prototypes. The fluorination kinetics of the experimental samples were studied empirically. The combination of macroscopic surface design (through FFF 3D printing) and microscopic surface modification (through gas-phase fluorination) permitted a significant reduction in the straining friction coefficient and increased the wettability of the complex-shaped 3D-printed products. Full article