Solvent Blends Research Articles

Glyoxylic‐Acetal‐Based Gel‐Polymer Electrolytes for Lithium‐Ion Batteries

AbstractThis work focuses on the combination of two strategies to improve the safety of lithium‐ion batteries: The use of a glyoxylic‐acetal, 1,1,2,2‐tetraethoxyethane, in the solvent blend to reduce the flammability of the liquid electrolyte and further its confinement inside of a methacrylate‐based polymer matrix, to prevent electrolyte leakage from the battery cells. Physicochemical characterizations of this novel gel‐polymer electrolyte (GPE) confirm its improved thermal properties and suitable ionic conductivity, as well as electrochemical stability window. Tests in LFP and hard carbon half‐cells vs. lithium metal show that the combination of glyoxylic‐acetal‐based electrolyte and the methacrylate‐based polymer matrix can promote lithium‐ion intercalation and deintercalation with stable capacity values. The application in lithium‐ion battery full cells furthermore shows that the GPE can promote a similar performance compared to the respective liquid electrolyte and can therefore make possible the realization of energy storage devices with improved safety characteristics.

Correlation of dopant solution on doping mechanism and performance of F4TCNQ‐doped P3HT

AbstractUnderstanding the doping mechanism between the dopants and the conjugated polymers (CPs) is crucial for efficiently utilizing the doping process in a controllable manner. In this work, we doped the poly(3‐hexylthiophene) (P3HT) films with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) from a chlorobenzene/acetonitrile (CB/AN) solvent blend and pure AN solvent by using the common sequential doping method. We found that the dissolution ability of the dopant solvent to P3HT and the concentration of the dopant solution were two critical factors to determine the doping process (solution doping or sequential doping) and the doping region (the amorphous or the crystalline phase). When the concentration of the dopant solution was low, solution doping was dominant in the P3HT film doped with F4TCNQ CB/AN solution, and the amorphous regions were doped in the P3HT film doped with F4TCNQ AN solution. With the increase of the dopant solution concentration, the ratio of ordered integer charge transfer (ICT) species, which formed from sequentially doped crystalline domains in the P3HT precast film, increased. Based on the above doping mechanism, a P3HT film with good electrical and tensile performance could be constructed by doping from F4TCNQ CB/AN solution with a relatively low concentration. Our work indicates that the dissolution or swelling ability of the dopant solvent to CP is an important factor in determining not only the doping mechanism but also the electrical and mechanical performances of doped CP films.

Low-Viscosity Nonaqueous Sulfolane–Amine–Methanol Solvent Blend for Reversible CO2 Capture: Part II. Blend Optimization, Water Effect, and Speciation

Low-Viscosity Nonaqueous Sulfolane–Amine–Methanol Solvent Blend for Reversible CO₂ Capture: Part II. Blend Optimization, Water Effect, and Speciation

In vivo Metabolic Sensing of Hyperpolarized [1‐13C]Pyruvate in Mice Using a Recyclable Perfluorinated Iridium Signal Amplification by Reversible Exchange Catalyst

AbstractReal‐time visualization of metabolic processes in vivo provides crucial insights into conditions like cancer and metabolic disorders. Metabolic magnetic resonance imaging (MRI), by amplifying the signal of pyruvate molecules through hyperpolarization, enables non‐invasive monitoring of metabolic fluxes, aiding in understanding disease progression and treatment response. Signal Amplification By Reversible Exchange (SABRE) presents a simpler, cost‐effective alternative to dissolution dynamic nuclear polarization, eliminating the need for expensive equipment and complex procedures. We present the first in vivo demonstration of metabolic sensing in a human pancreatic cancer xenograft model compared to healthy mice. A novel perfluorinated Iridium SABRE catalyst in a fluorinated solvent and methanol blend facilitated this breakthrough with a 1.2‐fold increase in [1‐13C]pyruvate SABRE hyperpolarization. The perfluorinated moiety allowed easy separation of the heavy‐metal‐containing catalyst from the hyperpolarized [1‐13C]pyruvate target. The perfluorinated catalyst exhibited recyclability, maintaining SABRE‐SHEATH activity through subsequent hyperpolarization cycles with minimal activity loss after the initial two cycles. Remarkably, the catalyst retained activity for at least 10 cycles, with a 3.3‐fold decrease in hyperpolarization potency. This proof‐of‐concept study encourages wider adoption of SABRE hyperpolarized [1‐13C]pyruvate MR for studying in vivo metabolism, aiding in diagnosing stages and monitoring treatment responses in cancer and other diseases.

In vivo Metabolic Sensing of Hyperpolarized [1-13C]Pyruvate in Mice Using a Recyclable Perfluorinated Iridium Signal Amplification by Reversible Exchange Catalyst.

Real-time visualization of metabolic processes in vivo provides crucial insights into conditions like cancer and metabolic disorders. Metabolic magnetic resonance imaging (MRI), by amplifying the signal of pyruvate molecules through hyperpolarization, enables non-invasive monitoring of metabolic fluxes, aiding in understanding disease progression and treatment response. Signal Amplification By Reversible Exchange (SABRE) presents a simpler, cost-effective alternative to dissolution dynamic nuclear polarization, eliminating the need for expensive equipment and complex procedures. We present the first in vivo demonstration of metabolic sensing in a human pancreatic cancer xenograft model compared to healthy mice. A novel perfluorinated Iridium SABRE catalyst in a fluorinated solvent and methanol blend facilitated this breakthrough with a 1.2-fold increase in [1-13C]pyruvate SABRE hyperpolarization. The perfluorinated moiety allowed easy separation of the heavy-metal-containing catalyst from the hyperpolarized [1-13C]pyruvate target. The perfluorinated catalyst exhibited recyclability, maintaining SABRE-SHEATH activity through subsequent hyperpolarization cycles with minimal activity loss after the initial two cycles. Remarkably, the catalyst retained activity for at least 10 cycles, with a 3.3-fold decrease in hyperpolarization potency. This proof-of-concept study encourages wider adoption of SABRE hyperpolarized [1-13C]pyruvate MR for studying in vivo metabolism, aiding in diagnosing stages and monitoring treatment responses in cancer and other diseases.

Solubility of 2,5-Furandicarboxylic Acid in Pure and Mixed Organic Solvent Systems at 293 K Predicted Using Hansen Solubility Parameters.

Central to the production of polyethylene furanoate (PEF), a bioplastic that could potentially replace petroleum-derived plastics, is 2,5-furandicarboxylic acid (FDCA). FDCA is a chemical derived from biomass that has low solubility in traditionally used solvents such as water. Thus, identifying solvents that can solubilize significant amounts of FDCA could allow for lower PEF production costs. In this study, FDCA solubility was investigated in nine pure solvents including H2O, acetonitrile (ACN), γ-valerolactone (GVL), γ-butyrolactone (GBL), ethanol (EtOH), methanol (MeOH), dimethyl sulfoxide (DMSO), sulfolane (SULF), and tetrahydrofuran (THF), eight binary, and three ternary solvent blends at 293 K. For all binary systems excluding DMSO and MeOH, the solubility of FDCA increased 1.5-65 times compared to the pure organic solvent, and the FDCA solubility was at least 10 times higher when compared to pure water. Specifically, the 20/80 w/w H2O/DMSO system solubilized 23.1 wt % FDCA, the highest of any binary blend studied, and 190 times more solubility than in pure water. In 20/80 w/w H2O/THF, the FDCA solubility was 60 times higher than pure water. In ternary blends that included DMSO, H2O, and either GVL, THF, or SULF, solubility increased by at least 6.6 times relative to the pure secondary organic component and 54 times relative to pure water. Using Hansen solubility parameters (HSPs), the radius of interaction (R i,j ) was found to be more strongly correlated to FDCA solubility than individual HSPs or the total solubility parameter. A MATLAB-based optimization code was developed and successful in minimizing the R i,j of a solvent blend to maximize FDCA solubility in binary and ternary aqueous solvents.

Development of a tobramycin-loaded calcium alginate microsphere/chitosan composite sponge with antibacterial effects as a wound dressing

Traditional dressings exhibit several disadvantages, as they frequently lead to bacterial infections, cause severe tissue adhesion and perform a relatively single function. Therefore, in this study, a composite sponge dressing with antibacterial properties and excellent physicochemical properties was developed. Six groups of tobramycin-loaded calcium alginate microspheres were prepared by changing the amount of tobramycin added, and the optimal group was selected. Then, seven groups of tobramycin-loaded calcium alginate microsphere/chitosan composite sponges were fabricated via a solvent blending process and a freeze-drying method. The surface morphology, physicochemical properties, in vitro degradation properties, in vitro drug release properties, antibacterial properties and cytotoxicity of the composite sponges were examined. Group 3.0 contained the best microspheres with the largest drug loading capacity, good swelling performance and cumulative drug release rate, obvious and sustained antibacterial activity, and good cytocompatibility. The tobramycin-loaded calcium alginate microsphere/chitosan composite sponges exhibited three-dimensional porous structures, and their porosity, swelling rate, water absorption and water retention rates and water vapor transmission rate met the standards needed for an ideal dressing. The comprehensive performance of the sponge was best when 20 mg of drug-loaded microspheres was added (i.e. group 20). The cumulative drug release rate of the sponge was 29.67 ± 4.14% at 7 d, the diameters of the inhibition zones against the three bacteria were greater than 15 mm, and L929 cell proliferation was promoted. These results demonstrated that the tobramycin-loaded calcium alginate microsphere/chitosan composite sponge with 20 mg of tobramycin-loaded microspheres shows promise as a dressing for infected wounds.

Flowback Additive for Acidizing Fluid to Stimulate Carbonate Gas Reservoirs

Summary Acidizing of oil- and gas-bearing carbonate reservoirs is generally undertaken by using strong mineral acids such as hydrochloric acid (HCl) to enhance permeability. One of the major challenges associated with HCl injection is tuning the reactivity profile to favor the transport of live acid deep into the reservoir while achieving a minimum rock face dissolution. The mineral acid is therefore emulsified in a hydrocarbon phase (e.g., diesel) to retard its reactivity with the rock matrix. The use of emulsified acid is hindered by several limitations such as low emulsion stability at high temperatures, pumping limitations due to high viscosity, the potential of formation damage, and cumbersome mixing procedures at the field scale. In addition, the brines formed as a result of this reaction can be difficult to produce due to higher density and capillary pressures, unfavorable wettability, and low formation pressure. Here, we report on the development of dual-purpose additives that were specifically designed to enhance the recovery of high-density brines and retard the acid/rock reactivity upon addition to the stimulation treatment. Accordingly, seven new additives with fluid flowback properties were developed for use in a single-phase acidizing fluid consisting of HCl (15 wt% and 28 wt%) with the required additives, such as corrosion inhibitor and intensifier, and H2S scavenger. The flowback enhancers (FBEs) were formulated from a blend of water, ester or terpene solvents, alcohols, and surfactants to form optically clear nano- and microemulsions. Surfactant selection was driven by the need to exhibit demulsification properties with condensate, high chemical and thermal stability, compatibility in strongly acidic media, and high-density brines under harsh reservoir conditions. To assess the FBE performance in acidizing formulations (i.e., to serve as both an FBE and retarder), screening studies consisting of static rock dissolution tests and surface tension measurements were performed to downselect FBEs suitable for this application. This was coupled with brine displacement tests in addition to compatibility and stability studies. FBEs that demonstrated superior performance were then selected for further evaluation under reservoir conditions [i.e., core flow matrix acidizing to measure regained permeability and computed tomography (CT) scan for analyzing the wormhole propagation]. The droplet size of the as-prepared nano- and microemulsions was found to be between 10 nm and 850 nm. The FBEs formulated in this study were found to prevent emulsion formation in the presence of condensate and demonstrated remarkable chemical and thermal stability in concentrated acid at temperatures up to 300°F for a duration of up to 24 hours, as confirmed by the consistent low surface tension values (21–29 mN/m). With regard to fluid displacement, column tests performed under ambient conditions revealed quick brine displacement with recovery exceeding 75 vol% in comparison with 16 vol% in the absence of the FBE. Interestingly, the addition of a select FBE from this study to 28 wt% HCl was found to retard the reaction of carbonate dissolution at room temperature. This led us to assess the performance under reservoir conditions utilizing core flow testing. Accordingly, the addition of FBE-F to 28 wt% HCl led to an improvement in permeability by up to 267% as compared with 15% without FBE added. These results are further supported by the CT scan images of the acidized cores, which revealed the formation of a deeper wormhole in the presence of a select FBE.

Evaluating solvent efficiency for carbon capture: Comparative analysis of temperature, concentration and diffusivity effects

In the pursuit of efficient carbon capture technologies, the selection and design of solvents play a pivotal role, directly impacting various crucial factors such as CO2 absorption capacity, equipment size, and regeneration energy requirements. The primary focus is on optimizing solvent systems through a comprehensive analysis of intermolecular interaction intensity, diffusion coefficient, and intra-molecular interaction intensity. This study employs a molecular dynamics simulation model to identify the most suitable solvent system by assessing the effect of operating variables like temperature, concentration, interaction intensity, and diffusivity of various single and blended amine systems. The assessment utilizes the radial distribution function and mean square displacement analysis. The results indicate that intermolecular interactions with CO2 are most significant in 30 wt% 2EAE, 40 wt% 2DMAE and 10% DMCA with 20% MCA ratio concentrations. TMPAD, in particular, stands out for its high repulsive interaction and low energy requirement for breaking the carbamate/bicarbonate ion. Diffusion behavior in various observed solvent systems is as follows: EAE > MEA > DMAE > MAE-DEAB > MAE-DMA2P > EAE-TMPAD > AMP-PZ > EAE-DEAB > MAE-TMPAD > EAE-DMA2P > MAE-DMAE > EAE-DMAE > TMPAD > MEA-AMP > DMA2P > DMCA-MCA > DEAB > MEA-PZ. Moreover, elevated temperatures facilitate enhanced diffusivity, leading to accelerated mass transfer rates. This implies the possibility of reducing the size of absorber units and lowering energy consumption. Further studies on heat of absorption and kinetic characteristics of solvent blends are necessary to ensure their practical applicability in carbon capture and industrial operations.

Fluoroethylene Carbonate: Bis(2,2,2,) Trifluoroethyl Carbonate as High Performance Electrolyte Solvent Blend for High Voltage Application in NMC811|| Silicon Oxide‐Graphite Lithium Ion Cells

LiNixMnyCozO2 cathode materials combined with Si‐based anode materials are current state‐of‐the‐art high energy density chemistries for lithium ion batteries. Increasing the upper cut‐off voltage is an intriguing approach to achieve even higher energy density in lithium ion batteries. However, poor oxidation stability of the state‐of‐the‐art electrolytes leads to transition metal dissolution (TMD), migration, and deposition (TMDMD) on the negative electrode, followed by sudden and rapid capacity fade. Furthermore, the chemical instability of the lithium hexafluorophosphate causes hydro‐fluoric acid to develop, which targets the native SiOx layers on silicon anodes and breaks the chemical bond to the carboxymethylcellulose sodium salt binder. Herein, a fluorine‐rich electrolyte formulation consisting of lithium‐bis(fluorsulfonyl)imide with fluoroethylene carbonate (FEC): bis(2,2,2,) trifluoroethyl carbonate (BFEC) was applied in NMC811||10%SiOx‐90%graphite cells to achieve high oxidation stability and prevent TMD and deposition. Up‐to‐date, this is the premier electrochemical performance reported in literature with a capacity retention of 94.5% and 92.2% with 0.5 °C and 4.5 V upper cut‐off voltage cycling at 20 and 40 °C after 100 cycles, respectively. The post mortem analysis showed that stabilization is achieved by forming inorganic‐ and salt‐rich interphases that protect the electrolyte versus decomposition at the electrode.

Fabrication and evaluation of organoclay-reinforced epoxidized natural rubber nanocomposites: A comprehensive study

The objective of this study is to assess the impact of incorporating a dual-functionalized organoclay with amine groups on the morphology and thermal characteristics of nanocomposites based on epoxidized natural rubber (ENR). To achieve this, organomodified montmorillonite clay (Cloisite30B) underwent treatment with 3-aminopropyltriethoxysilane (APS) via a silanization reaction, aiming to promote better interaction and compatibility between the two components. The structural and thermal properties of the resulting amine-functionalized Cloisite30B (f-C30B) were analyzed using infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Subsequently, various amounts of f-C30B (0, 1, 2.5, 5, 7.5, or 10 phr) were dispersed successfully in the ENR matrix using a solvent blending technique to create ENR/f-C30B nanocomposites. Standard techniques, including XRD, transmission electron microscopy (TEM), and TGA, were employed to analyze the nanocomposites for their structure and morphology. The morphological analysis revealed a uniform distribution of f-C30B throughout the ENR matrix. Moreover, TGA analysis indicated higher decomposition temperatures for ENR with f-C30B: 341 °C, 339 °C, 341 °C, 348 °C, and 352 °C for 1, 2.5, 5, 7.5, and 10 phr f-C30B, respectively, enhancing thermal stability. Char residues also rose accordingly: 2.3%, 1.9%, 3.7%, 4.9%, and 7.8%, respectively.Overall, this study highlights the potential of f-C30B as effective reinforcing agents in ENR-based nanocomposites, offering enhanced thermal stability, homogeneity, and valuable insights for the development of advanced ENR nanocomposites.

The Effect of Using Clay-CaCO<sub>3</sub> as Filler on Tensile Strength, %Elongation, and Young's Modulus Value in Modified Poly Lactic Acid (PLA)

Plastic is an important necessity with the characteristics of being light, strong, relatively cheap, and durable. However, plastic cannot decompose in a short time so that it becomes a pollutant. The using of Poly lactic acid (PLA) is an alternative to synthetic plastics substitute such as Low-Density Polyethylene (LDPE) because it is degradable. However, PLA is brittle, so it requires a plasticizer in the form of additives, namely Polyethylene glycol (PEG) 200 and fillers in the form of clay and CaCO3 to improve the mechanical properties of PLA which is brittle and has poor toughness. The purpose of this study was to determine the effect of adding additives to mechanical properties of PLA. The method used is solvent blending using chloroform as a solvent, stirring at 200 rpm for 6 hours at 30 . The research was conducted through testing the effect of the ratio of filler addition on the condition that the ratio of PLA/Additives was constant, i.e., 70%PLA/30% Additives. The resulting film is white and slightly transparent and has a smooth surface. The effect of adding additives in the form of plasticizers and fillers was tested through Dynamic Mechanical Analysis (DMA) analysis to determine the value of tensile strength, Young's modulus, and elongation break. The best result was obtained at a ratio of 25%CaCO3/Clay, which was increasing elongation at break 7.62%. It also indicated with best decreased percentage value of Young’s modulus, and highest crystallinity index of 39.86%. The worst value is obtained in variant of 50%CaCO3/Clay that indicated with lowest tensile strength and decreased of % elongation at break. From this study, the best variant was recommended as a laminating plastic, that does not require high tensile strength for application.

Analyzing of L-tryptophan thermodynamics and its solubility in aqueous acetonitrile blends at diverse temperatures

This paper delves into an investigation of the solubility characteristics of L-tryptophan within binary solvent systems containing aqueous acetonitrile. The primary emphasis of the study revolves around assessments based on mole fractions. The study utilizes these solubility values to assess thermodynamic constraints, including solution entropies and solution transfer free energetics. The calculated thermodynamic energies are correlated with interaction parameters, including Gibbs free energies and entropies, pertaining to the transfer of L-tryptophanfrom water to binary solvent blends of acetonitrile and water. Mathematical expressions are utilized to determine the transfer Gibbs free energies for chemical interactions, and the consequent entropies are clarified within the framework of solvent-solvent interactions. To expound upon the stability of L-tryptophan within the water-acetonitrile mixed system, we investigate the energetic aspects related to the transfer of chemicals Gibbs free energies. Additionally, standard temperature (298.15 K) is employed to calculate various related physicochemical parameters of solute/solvent.

Engineering Dry Electrode Manufacturing for Sustainable Lithium-Ion Batteries

The pursuit of industrializing lithium-ion batteries (LIBs) with exceptional energy density and top-tier safety features presents a substantial growth opportunity. The demand for energy storage is steadily rising, driven primarily by the growth in electric vehicles and the need for stationary energy storage systems. However, the manufacturing process of LIBs, which is crucial for these applications, still faces significant challenges in terms of both financial and environmental impacts. Our review paper comprehensively examines the dry battery electrode technology used in LIBs, which implies the use of no solvents to produce dry electrodes or coatings. In contrast, the conventional wet electrode technique includes processes for solvent recovery/drying and the mixing of solvents like N-methyl pyrrolidine (NMP). Methods that use dry films bypass the need for solvent blending and solvent evaporation processes. The advantages of dry processes include a shorter production time, reduced energy consumption, and lower equipment investment. This is because no solvent mixing or drying is required, making the production process much faster and, thus, decreasing the price. This review explores three solvent-free dry film techniques, such as extrusion, binder fibrillation, and dry spraying deposition, applied to LIB electrode coatings. Emphasizing cost-effective large-scale production, the critical methods identified are hot melting, extrusion, and binder fibrillation. This review provides a comprehensive examination of the solvent-free dry-film-making methods, detailing the underlying principles, procedures, and relevant parameters.

Enhanced Bioethanol Production from Corn Stover Using Choline Chloride and Lactic Acid Pretreatment: A Gravimetric analysis Approach

The transition to renewable energy sources necessitates the development of efficient and sustainable bioethanol production methods. This study investigates the use of a deep eutectic solvent (DES) blend of choline chloride and lactic acid for the pretreatment of corn stover, a widely available lignocellulosic biomass, to enhance cellulose yield and bioethanol production. The gravimetric method was employed to quantify cellulose yield post-pretreatment, providing a direct assessment of pretreatment efficacy. The study further evaluated the subsequent steps of enzymatic hydrolysis, fermentation, and distillation to determine the overall bioethanol yield. Results demonstrated that the choline chloride and lactic acid blend effectively disrupted the lignocellulosic structure of corn stover, significantly increasing cellulose accessibility and fermentable sugar release. The optimized pretreatment process led to a notable improvement in bioethanol yield, highlighting the potential of this method for commercial bioethanol production. This research contributes to the advancement of biofuel technologies and supports the broader goal of achieving sustainable energy solutions by demonstrating a viable approach to enhancing the efficiency and sustainability of lignocellulosic bioethanol production.

A COMPREHENSIVE REVIEW OF THE SELF-EMULSIFYING DRUG DELIVERY SYSTEM (SEDDS) AND ITS RECENTLY DEVELOPED FORMULATIONS

Background: Poor water solubility of the therapeutic compounds has become a very challenging issue for the delivery of drugs through conventional approaches. Over 40% of newly discovered active compounds also have a lack of water solubility and are lipophilic in nature. One approach for increasing the oral bioavailability of therapeutic agents is to deliver the drug via a self-emulsifying drug delivery system (SEDDS). Although many studies have been carried out, there are few drug products on the pharmaceutical market formulated as SEDDS, confirming the difficulty of formulating hydrophobic drug compounds into such formulations. Objectives: This review aims to describe the SEDDS formulation, its composition, as well as the manufacturing techniques and recently developed formulations, and also highlights an important characterization test for the evaluation of SEDDS. Methodology: Relevant literature was searched in English using different databases, i.e. Google Scholar, PubMed, and Scopus. Results: Within recent years, SEDDS was also discovered for oral administration of hydrophilic macromolecular drugs such as peptides, proteins, polysaccharides and pDNA. SEDDS are stable blends of surfactants, oils, solvents, and co-solvents. This system of drug delivery is useful for improving the aqueous solubility of drugs. They could be manufactured by the spray cooling method, the melt granulation process, the lyophilization technique, and by extrusion or spheronization. Various characterization tests, such as zeta potential, viscosity, dispersibility, cloud test, percentage transmittance, etc., could also be performed to confirm the stability of the SEEDS. Conclusion: Recently, many formulations have been developed for the delivery of drugs through the use of SEEDS and have shown increased bioavailability of the drug, as well as many promising outcomes.

Solvent blends for selective elastane dissolution and recovery from mixed polyamide fabrics

The textile industry faces significant challenges in recycling of fibres from clothes due to the complex blends of natural and synthetic polymers that are used in their production. One of the challenges is the inclusion of elastane, that is added in textile constructions to provide stretch and comfort. It is generally present in small proportions, but even in such low amounts it interferes in recycling of the other polymer types in clothing. Thus, the elastane needs to be removed from textile blends to improve fibre recycling rates. The typical solvents for elastane, dimethylformamide (DMF) and dimethylacetamide (DMAc), are toxic and not environment friendly, which makes it difficult to handle them in large quantities. This study focuses on the selective separation of elastane from clothing by dissolution/precipitation method. It will be shown that elastane can be separated at room temperature, by mixing two solvents at a specific ratio.

Room Temperature Evaporation Behavior of Homogeneous Azeotropes Used in Art Conservation Cleaning Treatments

Cleaning painted surfaces of their grime, aged varnishes, and discolored overpaint is one of the most common interventive treatments for art conservators. Carefully concocted solvent mixtures navigate the solubility differences between the material removed and the original paint underneath. However, these solutions may be altered by differential evaporation rates of the component solvents (zeotropic behavior), potentially leading to ineffectively weak cleaning or conversely overly strong residual liquid capable of damaging the underlying paint. Azeotropic solvent blends, which maintain a constant composition during evaporation, offer a promising solution. These blends consist of two or more solvents combined at precise concentrations to function as a single solvent. Additionally, pressure-maximum azeotropes feature higher vapor pressure compared to other mixtures, further minimizing contact time and sorption of the solvents into artworks. This study examines azeotropes of isopropanol with n-hexane and 2-butanone in cyclohexane, which have been used previously in art conservation. The evaporation behavior at room temperature of these boiling point azeotropes was assessed using vapor pressure measurements, refractive index determinations, gravimetric analysis, and gas chromatography. Results showed changes in composition during evaporation and found that the actual room temperature azeotropic composition can vary between 1 and 10% v/v in concentration with those commonly reported at their boiling points. Art conservators should be cautious when using azeotropic blends reported at boiling points significantly higher than room temperature. To ensure the safety and efficacy of these mixtures, it is recommended to determine individual azeotropic cleaning blends experimentally before their use.

Exfoliated Poly (styrene-co-urethane) Grafted - Polymethylmethacrylate /Layered Double Hydroxide Nanocomposite Synthesized by Metal Catalyzed Living Radical Polymerization and Solvent Blending Method

Exfoliated Poly (styrene-co-urethane) Grafted - Polymethylmethacrylate /Layered Double Hydroxide Nanocomposite Synthesized by Metal Catalyzed Living Radical Polymerization and Solvent Blending Method

Comparative analysis of artificial neural network (ANN) models: CO2 loading in MDEA and blended MDEA/PZ solvents

CO2 loading plays a vital role in gauging a solvent's capability to absorb CO2 from combustion gases and natural gas flow. Yet, the customary approaches for measuring CO2 loading hinge on laborious and costly laboratory experiments. Therefore, researchers employed artificial neural network (ANN) approaches to estimate CO2 loading using various datasets, although case-specific methods and approaches restricted their attempts. This study employed two datasets with 303 (CO2 absorption via MDEA) and 361 (CO2 absorption via MDEA/PZ) acceptable experimental data to create ANN models to estimate CO2 loading in aqueous amine solvents. The CO2 loading is evaluated using a wide range of input parameters, including temperature, CO2 partial pressure, Methyldiethanolamine (MDEA) solvent, and Piperazine (PZ) solvent for cases A and B, respectively. Twelve distinct training algorithms, four distinct activation functions, and three hidden layers with neuron variations created the models. ANN models trained with a blend of PZ and MDEA solvents generated more accurate predictions compared to models trained with solely MDEA solvent. The sigmoidal activation functions (Tansig and Logsig) generated more precise predictions than the linear activation functions (Poslin and Purelin). In addition, “Levenberg-Marquardt (lm)” with the highest coefficient of determination (R2) was selected as the best training algorithm among the twelve training functions. The best average coefficients of determination were determined to be 0.964 for the tansig activation function with [25 18 10] number of neurons in case A and 0.967 for the logsig activation function with [30 20 12] number of neurons in case B. The statistical analysis (R2, MSE, RMSE, AAD, AARD, and run time) confirmed that the network provided accurate estimates of CO2 loading for both datasets. The prediction potential of the network is then further indicated by model generalization inside the training data set.