Search Results (31)

The growing demand for high-energy, safe, and sustainable lithium-ion batteries has increased interest in nickel-rich cathode materials and solid-state electrolytes. This study presents a scalable wet-processing method for fabricating composite cathodes for all-solid-state batteries. The cathodes studied herein are high-nickel LiNi_0.90Mn_0.05Co_0.05O₂, NMC955, the sulfide-based electrolyte Li₆PS₅Cl, and alternative binders—polyvinyl alcohol (PVA) and polyisobutylene (PIB)—dispersed in toluene, a non-polar solvent compatible with the electrolyte. After fabrication, the cathodes were characterized using SEM/EDX, sheet resistance, and Hall effect measurements. Electrochemical tests were additionally performed in all-solid-state battery half-cells comprising the synthesized cathodes, lithium metal anodes, and Li₆PS₅Cl as the separator and electrolyte. The results show that both PIB and PVA formulations yielded conductive cathodes with stable microstructures and uniform particle distribution. Electrochemical characterization exposed that the PVA-based cathode outperformed the PIB-based counterpart, achieving the theoretical capacity of 192 mAh·g⁻¹ even at 1C, whereas the PIB cathode reached a maximum capacity of 145 mAh.g⁻¹ at C/40. Post-mortem analysis confirmed the structural integrity of the cathodes. These findings demonstrate the viability of NMC955 as a high-capacity cathode material compatible with solid-state systems. Full article

In offshore oil and gas extraction, riser pipes serve as the first isolation barrier for wellbore integrity, playing a crucial role in ensuring operational safety. Protective coatings represent an effective measure for corrosion prevention in riser pipes. To address issues such as electrochemical corrosion and poor adhesion of existing coatings, this study developed an underwater-curing composite material based on a polyisobutylene (PIB) and butyl rubber (IIR) blend system. The material simultaneously exhibits high peel strength, low water absorption, and stability across a wide temperature range. First, the contradiction between material elasticity and strength was overcome through the synergistic effect of medium molecular weight PIB internal plasticization and IIR crosslinking networks. Second, stable peel strength across a wide temperature range (−45 °C to 80 °C) was achieved by utilizing the interfacial effects of nano-fillers. Subsequently, an innovative solvent-free two-component epoxy system was developed, combining medium molecular weight PIB internal plasticization, nano-silica hydrogen bond reinforcement, and latent curing agent regulation. This system achieves rapid surface drying within 30 min underwater and pull-off strength exceeding 3.5 MPa. Through systematic laboratory testing and field application experiments on offshore oil and gas well risers, the material’s fundamental properties and operational performance were determined. Results indicate that the material exhibits a peel strength of 5 N/cm on offshore oil risers, significantly extending the service life of the riser pipes. This research provides theoretical foundation and technical support for improving the efficiency and reliability of repair processes for offshore oil riser pipes. Full article

Molecular modeling calculations for the design and improvement of next-generation additives for motor oils have reached a level that can support and improve experimental results. The regulation of insoluble sludge nanoparticle aggregations within oil and on engine pistons is a critical performance metric for lubricant oil additives. There is a general agreement regarding the mechanism of deposit formation which is attributed to the self-aggregation of nano-sized carbon rich insoluble structures. Dispersants are a primary category of additives employed to inhibit aggregation in lubricant formulations. Along with the base oil, they are crucial in dispersing and stabilizing insoluble particles to manage the formation of deposits. In this study, multiscale modeling methods were used to elucidate molecular mechanism of deposit control via polyisobutylene-bis-succinimide (PIBSI) dispersants by using density functional theory (DFT), molecular dynamics (MD) simulations of cells constructed by statistical sampling of molecular configurations, and coarse-grained (CG) simulations. The aim of this study was to understand the role of different groups such as succinimide, amine center, and two polyisobutylene (PIB) tails in PIBSI dispersants. It was demonstrated that the mechanism of deposit control by the polymer-based PIBSI dispersant can be elucidated through the interactions among various constituents, including hydrogen bonding and hydrophilic–hydrophobic interactions. We showed that sludge type nanoparticle aggregation is mitigated by intercalation of polar amine central groups of dispersant between the nanoparticles followed by the extension of two hydrophobic PIB chains into the oil phase that decreases coalesce further by forming a hydrophobic repulsive layer. Full article

The influence of organosilicon compounds on butyl sealant blends’ mechanical and processing properties was investigated, particularly under increased humidity conditions. The addition of (3-mercaptopropyl)trimethoxysilane (MPTES), (3-aminopropyl)triethoxysilane (APTES), vinyltrimethoxysilane (VTMOS), and (3-glycidoxypropyl)trimethoxysilane (GLYMO) to elastomeric blends containing butyl rubber (IIR) and polyisobutylene (PIB) was studied. Key rheological parameters, including Mooney viscosity and melt volume rate (MVR), along with mechanical attributes such as peel resistance and cone penetration, were evaluated. Results indicated that functionalized silanes enhance sealant cohesion when their functional groups interact with the matrix and form cross-links under humid conditions. The presence of unreacted silanes acts as a plasticizer, increasing MVR and reducing viscosity. A notable MVR increase, up to 109 mL/10 min, was observed for the APTES-10 system. The most significant mechanical property enhancements were observed in blends containing MPTES and APTES, resulting in increased cohesion and peel resistance. The findings of this research are of considerable practical relevance, demonstrating that the modification of rubber sealants with monofunctional silanes improves their cohesion, delamination resistance, and processability, thereby making these materials suitable for the production of more durable sealants. Full article

Trace concentrations of dyes are often present in textile wastewater streams and present a serious environmental problem. Thus, these dyes must be removed from wastewater either by degradation or sequestration prior to discharge of the wastewater into the environment. Existing processes to remove these wastewater contaminants include the use of solid sorbents to sequester dyes or the use of biochemical or chemical methods of dye degradation. However, these processes typically generate their own waste products, are not necessarily rapid because of the low dye concentration, and often use expensive or non-recyclable sequestrants or reagents. This paper describes a simple, recyclable, liquid–liquid extraction scheme where ionic dyes can be sequestered into poly(α-olefin) (PAO) solvent systems. The partitioning of anionic and cationic dyes from water into PAOs is facilitated by ionic PAO-phase anchored sequestering agents that are readily prepared from commercially available vinyl-terminated polyisobutylene (PIB). This is accomplished by a sequence of reactions involving hydroboration/oxidation, conversion of an alcohol into an iodide, and conversion of the resulting primary alkyl iodide into a cationic nitrogen derivative. The products of this synthetic sequence are cationic nitrogen iodide salts which serve as anionic sequestrants that are soluble in PAO. These studies showed that the resulting series of cationic PIB-bound cationic sequestering agents facilitated efficient extraction of anionic, azo, phthalein, and sulfonephthalein dyes from water into a hydrocarbon PAO phase. Since the hydrocarbon PAO phase is completely immiscible with water and the PIB derivatives are also insoluble in water, neither the sequestration solvent nor the sequestrants contaminate wastewater. The effectiveness and efficiency of these sequestrations were assayed by UV–visible spectroscopy. These spectroscopic studies showed that extraction efficiencies were in most cases >99%. These studies also involved procedures that allowed for the regeneration and recycling of these PAO sequestration systems. This allowed us to recycle the PAO solvent system for at least 10 sequential batch extractions where we sequestered sodium salts of methyl red and 4′,5′-dichlorofluorescein dyes from water with extraction efficiencies of >99%. These studies also showed that a PIB-bound derivative of the sodium salt of 1,1,1-trifluoromethylpentane-2,4-dione could be prepared from a PIB-bound carboxylic acid ester by a Claisen-like reaction and that the sodium salt of this β-diketone could be used to sequester cationic dyes from water. This PIB-bound anion rapidly and efficiently extracted >99% of methylene blue, malachite green, and safranine O from water based on UV–visible and ¹H NMR spectroscopic assays. Full article

Plasma actuators have demonstrated great potential for active flow control applications, including boundary layer control, flow separation delay, turbulence control, and aircraft noise reduction. In particular, the material used as a dielectric barrier is crucial for the proper operation of the device. Currently, the variety of dielectrics reported in the literature is still quite restricted to polymers including Kapton, Teflon, poly(methyl methacrylate) (PMMA), Cirlex, polyisobutylene (PIB) rubber, or polystyrene. Nevertheless, several studies have highlighted the fragilities of polymeric dielectric layers when actuators operate at significantly high-voltage and -frequency levels or for long periods. In the current study, we propose the use of alumina-based ceramic composites as alternative materials for plasma actuator dielectric layers. The alumina composite samples were fabricated and characterized in terms of microstructure, electrical parameters, and plasma-induced flow velocity and compared with a conventional Kapton-based actuator. It was concluded that alumina-based dielectrics are suitable materials for plasma actuator applications, being able to generate plasma-induced flow velocities of approximately 4.5 m/s. In addition, it was verified that alumina-based ceramic actuators can provide similar fluid mechanical efficiencies to Kapton actuators. Furthermore, the ceramic dielectrics present additional characteristics, such as high-temperature resistance, which are not encompassed by conventional Kapton actuators, which makes them suitable for high-temperature applications such as turbine blade film cooling enhancement and plasma-assisted combustion. The high porosity of the ceramic results in lower plasma-induced flow velocity and lower fluid mechanical efficiency, but by minimizing the porosity, the fluid mechanical efficiency is increased. Full article

Polyisobutylene (PIB) is commonly used as a primary sealant in multi-layer insulating glazing elements, where temperatures often exceed 100 °C. At such conditions, PIB undergoes structural changes, causing different relaxation dynamics and leading to decreased lifetime of the material. Understanding thermal behavior is therefore imperative for achieving effective insulation of these materials for long-term use in insulating application. The present study was focused on the temperature dependence of viscoelastic behavior of two commercially available polyisobutylene (PIB) materials, which are commonly used as primary sealants for energy-efficient multi-layer glazing units. The long-term viscoelastic behavior of the materials before and after thermal treatment at high temperatures was studied by using time–temperature superposition (tTS). Van-Gurp–Palmen plots were obtained directly from experimental data and enabled the study of thermally induced changes, while the relaxation time spectra were calculated from master curves and enabled the calculation of molecular weight distribution. The results showed that, after thermal treatment, the structure of PIB materials changes from linear to branched, while the molecular weight distributions transition from monomodal to bimodal. The untreated samples exhibited viscous-like behavior, while the thermally stabilized samples exhibited solid-like behavior, extending the material response for ~6 decades towards a longer timescale. Moreover, the presented results can be directly used to simulate the mechanical responses of the sealants using currently available FEM software packages to predict their functional and structural lifetime. Full article

The polymerization of isobutylene allows us to obtain a wide spectrum of polyisobutylenes (PIBs) which differ in their molecular weight characteristics and the chemical structure of chain-end groups. The bulk of the PIBs manufactured worldwide are highly reactive polyisobutylenes (HRPIBs) with –C(Me)=CH₂ end-groups and low-molecular weights (M_n < 5 kDa). HRPIBs are feedstocks that are in high demand in the manufacturing of additives for fuels and oils, adhesives, detergents, and other fine chemicals. In addition, HRPIBs and CMe₂Cl-terminated PIBs are intensively studied with the aim of finding biomedical applications and for the purpose of developing new materials. Both chain control (molecular weight and dispersity) and chemoselectivity (formation of exo-olefinic or –CMe₂Cl groups) should be achieved during polymerization. This review highlights the fundamental issues in the mechanisms of isobutylene polymerization and PIB analysis, examines actual catalytic approaches to PIBs, and describes recent studies on the functionalization and applications of HRPIBs and halogen-terminated PIBs. Full article

The nature of the end-groups of a PIBSA sample, namely a polyisobutylene (PIB) sample, where each chain is supposedly terminated at one end with a single succinic anhydride group, was characterized through a combination of pyrene excimer fluorescence (PEF), gel permeation chromatography, and simulations. The PIBSA sample was reacted with different molar ratios of hexamethylene diamine to generate PIBSI molecules with succinimide (SI) groups in the corresponding reaction mixtures. The molecular weight distribution (MWD) of the different reaction mixtures was determined by fitting the gel permeation chromatography traces with sums of Gaussians. Comparison of the experimental MWD of the reaction mixtures with those simulated by assuming that the reaction between succinic anhydride and amine occurs through stochastic encounters led to the conclusion that 36 wt% of the PIBSA sample constituted unmaleated PIB chains. Based on this analysis, the PIBSA sample was found to be constituted of 0.50, 0.38, and 0.12 molar fractions of PIB chains that were singly maleated, unmaleated, and doubly maleated, respectively. Full article

In this paper, surface acoustic wave (SAW) technology based on love waves was designed in three dimensions for finite element modelling (FEM) and analysis in order to detect volatile organic compounds (VOC). A thin layer of polyisobutylene (PIB), which acted as the sensing layer, was placed on top of the guiding layer of SiO₂ and interdigitated electrodes (IDE), which were modelled on a piezoelectric substrate. The substrate selected was 64° YZ-cut Lithium niobate (LiNbO₃) for love wave generation, and the lightweight electrodes were made of Aluminium (Al). Analytical simulations were conducted using COMSOL Multiphysics 6.0 software. Full article

MXene films with a conductivity of about 4000 S/cm were obtained on glass substrates following a drop-casting method and characterized by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and Raman spectroscopy. The polymer coatings of polystyrene (PSt), polyisobutylene (PIB) and tri-block copolymer of polyisobutylene with styrene (SIBS) were deposited on MXene films and their efficiency toward the protection of MXenes against oxidative degradation was estimated at ambient conditions. A loss of conductivity was detected for PSt-coated MXene films after 220 days of storage, while pristine MXene films stored for 400 days were conductive and their resistivity increased by 2.5 times. Nonpolar polymer coatings based on polyisobutylene and tri-block copolymer of isobutylene with styrene showed ability to protect MXene films from oxidation during a long-term period. After 400 days of storage, the resistivity of the MXene films coated with PIB and SIBS increased by 1.8 and 1.4 times, respectively. The results obtained are of interest for expanding the industrial application of MXene films, increasing their operation by simple coating with nonpolar flexible polymers. Full article

This paper presents the FEM modeling and simulation of a thin-film bulk acoustic resonator (FBAR) for a tetrachloroethene (PCE) gas-sensing application. A zinc oxide layer is used as a piezoelectric material; an aluminum layer is used as the electrode material in the structure of the FBAR. Polyisobutylene (PIB) is used as the sensitive layer for PCE gas detection. The study was carried out in commercially available FEM-based COMSOL software. The proposed structure was exposed to six different organic gases with concentrations ranging from 0 to 1000 ppm. The structure showed high selectivity for PCE gas. Incorporating the 3rd-order Hilbert fractal geometry in the top electrode of the FBAR increased the sensitivity of the sensor which showed high selectivity for PCE gas detection. A sensitivity enhancement of 66% was obtained using fractal geometry on the top electrode of the FBAR without alteration in size or cost. In addition, a reduction in the cross-sensitivity was achieved. Further, the PIB layer thickness and active area of the FBAR were optimized to obtain high sensitivity. The equivalent circuit was also analyzed to understand the behavior of the sensing effect and mechanism. Full article

Carbonyl-centered hydrogen bonds with various strength and geometries are often exploited in materials to embed dynamic and adaptive properties, with the use of thiocarbonyl groups as hydrogen-bonding acceptors remaining only scarcely investigated. We herein report a comparative study of C2=O and C2=S barbiturates in view of their differing hydrogen bonds, using the 5,5-disubstituted barbiturate B and the thiobarbiturate TB as model compounds. Owing to the different hydrogen-bonding strength and geometries of C2=O vs. C2=S, we postulate the formation of different hydrogen-bonding patterns in C2=S in comparison to the C2=O in conventional barbiturates. To study differences in their association in solution, we conducted concentration- and temperature-dependent NMR experiments to compare their association constants, Gibbs free energy of association ∆G_assn., and the coalescence behavior of the N-H‧‧‧S=C bonded assemblies. In Langmuir films, the introduction of C2=S suppressed 2D crystallization when comparing B and TB using Brewster angle microscopy, also revealing a significant deviation in morphology. When embedded into a hydrophobic polymer such as polyisobutylene, a largely different rheological behavior was observed for the barbiturate-bearing PB compared to the thiobarbiturate-bearing PTB polymers, indicative of a stronger hydrogen bonding in the thioanalogue PTB. We therefore prove that H-bonds, when affixed to a polymer, here the thiobarbiturate moieties in PTB, can reinforce the nonpolar PIB matrix even better, thus indicating the formation of stronger H-bonds among the thiobarbiturates in polymers in contrast to the effects observed in solution. Full article

This paper presents the results of the first part of testing a novel electrospun fiber mat based on a unique macromolecule: polyisobutylene (PIB). A PIB-based compound containing zinc oxide (ZnO) was electrospun into self-supporting mats of 203.75 and 295.5 g/m² that were investigated using a variety of techniques. The results show that the hydrophobic mats are not cytotoxic, resist fibroblast cell adhesion and biofilm formation and are comfortable and easy to breathe through for use as a mask. The mats show great promise for personal protective equipment and other applications. Full article

Polyisobutylenes (PIB) constitute a versatile family of polymer materials that have been used mainly as fuel and lubricant additives. Particularly, the current commercial demand for highly reactive polyisobutylene (HR-PIB) products motivates the development of new processes and procedures to produce PIBs with high polymer yields, narrow molar mass distributions and high vinyl contents. For this reason, a bibliometric survey is presented here to map and discuss important technical aspects and technological trends in the field of solution cationic polymerization of isobutylenes. It is shown that investigations in this field are concentrated mainly on developed countries and that industrial initiatives indicate high commercial interest and significant investments in the field. It is also shown that use of catalyst systems based on AlCl₃ and ether cocatalysts can be very beneficial for PIB and HR-PIB manufacture. Finally, it is shown that investigations search for cheaper and environmentally friendly catalysts and solvents that can be employed at moderate temperatures, particularly for the production of HR-PIB. Full article