Search Results (214)

Moroccan oil shale ash (MOSA) represents an underutilized industrial by-product, particularly in the Rif region, where its high mineral content has often led to its neglect in value-added applications. This study highlights the successful conversion of MOSA into amorphous mesoporous silica (AS-Si) using a sol–gel process assisted by polyethylene glycol (PEG-6000) as a soft template. The resulting AS-Si material was extensively characterized to confirm its potential for environmental remediation. FTIR analysis revealed characteristic vibrational bands corresponding to Si–OH and Si–O–Si bonds, while XRD confirmed its amorphous nature with a broad diffraction peak at 2θ ≈ 22.5°. SEM imaging revealed a highly porous, sponge-like morphology composed of aggregated nanoscale particles, consistent with the nitrogen adsorption–desorption isotherm. The material exhibited a specific surface area of 68 m²/g, a maximum in the pore size distribution at a pore diameter of 2.4 nm, and a cumulative pore volume of 0.11 cm³/g for pores up to 78 nm. DLS analysis indicated an average hydrodynamic diameter of 779 nm with moderate polydispersity (PDI = 0.48), while a zeta potential of –34.10 mV confirmed good colloidal stability. Furthermore, thermogravimetric analysis (TGA) and DSC suggested the thermal stability of our amorphous silica. The adsorption performance of AS-Si was evaluated using methylene blue (MB) and ciprofloxacin (Cipro) as model pollutants. Kinetic data were best fitted by the pseudo-second-order model, while isotherm studies favored the Langmuir model, suggesting monolayer adsorption. AS-Si could be used four times for the removal of MB and Cipro. These results collectively demonstrate that AS-Si is a promising, low-cost, and sustainable adsorbent derived from Moroccan oil shale ash for the effective removal of organic contaminants from aqueous media. Full article

Background: The solubility and phase behavior of APIs are crucial for the development of medicines and ensuring their stability. However, conventional experimental approaches often do not allow for the precise determination of phase transitions and solubility limits, especially for poorly soluble compounds. Purpose: The aim of this study was to demonstrate the possibility of using the laser microinterferometry method, traditionally used to define the phase equilibria of polymer systems, to determine the thermodynamic solubility of the APIs. Methods: Using laser microinterferometry, the thermodynamic solubility and phase behavior of amorphous darunavir were determined in various pharmaceutical solvents, including vaseline and olive oils, water, glycerol, alcohols (methanol, ethanol, isopropanol), glycols (propylene glycol, polyethylene glycol 400, polypropylene glycol 425, polyethylene glycol 4000), and ethoxylated polyethylene glycol ether obtained from castor oil in the temperature range of 25–130 °C. Dissolution kinetics was estimated at 25 °C. Hansen solubility parameter calculations were also performed for comparison. Results: Darunavir is practically insoluble in olive and vaseline oils. In water and glycerol, an amorphous equilibrium with an upper critical solution temperature was observed, and phase diagrams were constructed for the first time. In alcohols, glycols, and ethoxylated polyethylene glycol ether obtained from castor oil, darunavir showed high solubility, accompanied by the formation of crystalline solvates. Kinetic evaluation showed that the dissolution rate of darunavir in methanol is four times faster than in ethanol and thirty times faster than in isopropanol. Comparison of the obtained data with previously published and calculated values of solubility parameters demonstrates a good correlation. Conclusions: Laser microinterferometry has been demonstrated as a potential tool for determining the thermodynamic solubility of APIs. This method allows for directly observing the dissolution process, determining the solubility limits, and detecting phase transitions. These studies are necessary for selecting appropriate excipients, preventing the formation of undesirable solvates and predicting formulation stability, which are all critical factors in early-stage drug development and pharmaceutical formulation design. Full article

Additive manufacturing (AM), particularly fused deposition modeling (FDM) 3D printing, has emerged as a versatile and accessible technology for prototyping and functional part production across a wide range of industrial applications. One of the critical performance-limiting factors in AM is the chemical resistance of thermoplastic materials, which directly influences their structural integrity, durability, and suitability in chemically aggressive environments. This study systematically investigates the chemical resistance of eight different widely utilized FDM filaments—acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polyamide (PA, Nylon), polycarbonate (PC), polyethylene terephthalate glycol (PETG), polylactic acid (PLA), polypropylene (PP), and polyvinyl butyral (PVB)—by examining their tensile strength and impact resistance after immersion in representative chemical agents: distilled water, ethanol (99.5%), isopropyl alcohol (75% and 99%), acetic acid (8%), hydrochloric acid (37%), hydrogen peroxide (30%), and acetone (99.5%). Quantitative mechanical testing was conducted in accordance with ASTM D638 and ASTM D256 standards, and statistical variability was accounted for using triplicate measurements with standard deviation analysis. The results reveal that PP exhibits the highest chemical resilience, retaining over 97% of its mechanical properties even after 7 days of immersion in aggressive solvents like acetone. PETG and ASA also demonstrated quite successful stability (>90% retention) in mildly corrosive environments such as alcohols and weak acids. In contrast, PLA, due to its low crystallinity and polar ester backbone, and PVB, due to its high amorphous content, showed substantial degradation: tensile strength losses exceeding 70% and impact resistance dropping below 20% in acetone. Moderate resistance was observed in ABS and PC, which maintained structural properties in neutral or weakly reactive conditions but suffered mechanical deterioration (>50% loss) in solvent-rich media. A strong correlation (r > 0.95) between tensile and impact strength reduction was found for most materials, indicating that chemical attack affects both static and dynamic mechanical performance uniformly. The findings of this study provide a robust framework for selecting appropriate 3D printing materials in applications exposed to solvents, acids, or oxidizing agents. PP is recommended for harsh chemical environments; PETG and ASA are suitable for moderate exposure scenarios, whereas PLA and PVB should be limited to low-risk, esthetic, or disposable applications. Full article

Lithium-ion batteries are restricted in development due to safety issues such as poor chemical stability and flammability of organic liquid electrolytes. Replacing liquid electrolytes with solid ones is crucial for improving battery safety and performance. This study aims to enhance the performance of polyethylene oxide (PEO)-based polymer via blending with poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)). The experimental results showed that the addition of P(VDF-HFP) disrupted the crystalline regions of PEO by increasing the amorphous domains, thus improving lithium-ion migration capability. The electrolyte membrane with 30 wt% P(VDF-HFP) and 70 wt% PEO exhibited the highest ionic conductivity, widest electrochemical window, and enhanced thermal stability, as well as a high lithium-ion transference number (0.45). The cells assembled with this membrane electrolyte demonstrated an excellent rate of performance and cycling stability, retaining specific capacities of 122.39 mAh g⁻¹ after 200 cycles at 0.5C, and 112.77 mAh g⁻¹ after 200 cycles at 1C and 25 °C. The full cell assembled with LiFePO₄ as the positive electrode exhibits excellent rate performance and good cycling stability, indicating that prepared solid electrolytes have great potential applications in lithium batteries. Full article

Poly(lactic acid) (PLA) is one of the most important bio-based and industrial compostable materials in food packaging. Its barrier properties towards oxygen and moisture are well documented. However, data on barrier properties of PLA towards organic molecules are scarce in the literature. This study investigated the diffusion of various organic molecules, including n-alkanes, 1-alcohols, 2-ketones, ethers, esters, amines, and aromatics, in two commercial PLA films with thicknesses of 20 µm and 30 µm. The diffusion coefficient (D_P) values were determined from lag time in permeation tests conducted at temperatures ranging from 20 °C to 90 °C. The films were also characterized in terms of crystallinity, rigid and mobile amorphous fractions, and molecular weight. Activation energies (E_A) were calculated based on the temperature dependence of the D_P using the Arrhenius approach. In total, 290 D_P values for 55 individual substances were determined, and 38 E_A values were derived from these data. The E_A correlated well with the molecular volume of the investigated substances. Moreover, the pre-exponential factor D₀ showed a correlation with E_A. These correlations enabled the establishment of diffusion modeling parameters for PLA, allowing the prediction of D_P for untested substances. The diffusion behavior of PLA was further compared with the literature data for polyethylene terephthalate and polyethylene naphthalate, providing insights into the relative performance of these materials. Full article

Steel fibers (STs), polyvinyl alcohol fibers (PVAs), and polyethylene fibers (PEs) were selected to systematically investigate the effects of different fiber types and dosages on the workability (slump and spread) and mechanical properties (compressive strength and splitting tensile strength) of slag–Yellow River sand geopolymer eco-cementitious materials. By combining microstructural testing techniques such as thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), the influence mechanisms of fibers on the characteristic products and microstructure of the matrix were thoroughly revealed, and the role of fibers in the strength development of Yellow River sediment-based geopolymers was elucidated. The results show that as the fiber content increases, the workability of the mixture significantly decreases. The appropriate incorporation of steel fibers and PVAs can significantly enhance the strength and toughness of the matrix. When the fiber dosage is 1%, the 28-day compressive strength of specimens with steel fibers and PVAs increased by 25.93% and 21.96%, respectively, compared to the control group, while the splitting tensile strength increased by 50.00% and 60.34%, respectively. However, the mechanisms of action differ significantly; steel fibers primarily enhance the compressive performance of the matrix through their high stiffness and strength, whereas PVAs inhibit crack propagation through their flexibility and excellent bonding properties. In contrast, the strength improvement of PEs is mainly reflected in toughening. When the fiber dosage is 1.5%, the 28-day splitting tensile strength of PE specimens increased by 72.61%, and the tensile-to-compressive ratio increased by 92.32% compared to the control group. Microstructural analysis indicates that the incorporation of different types of fibers does not alter the types of characteristic products in alkali-activated cementitious materials, but excessive fiber content affects the generation of gel-like products and the distribution of free water, thereby altering the thermal decomposition behavior of characteristic gel products. Additionally, the matrix incorporating PEs forms a honeycomb-like amorphous gel, resulting in weak interfacial bonding between the fibers and the matrix. This is one of the main reasons for the limited reinforcing effect of PEs at the microscopic scale and a key factor for their inferior long-term performance compared to steel fibers and PVAs. This study provides theoretical foundations and practical guidance for optimizing the performance of fiber-reinforced geopolymer materials. Full article

Poor water solubility remains a significant challenge in the pharmaceutical industry that limits the therapeutic efficacy and bioavailability of many active pharmaceuticals. Soluplus^® (SLP), an amphiphilic graft copolymer made of polyethylene glycol, polyvinyl caprolactam, and polyvinyl acetate, has been gaining interest in recent years as it addresses these limitations by acting as a versatile carrier. Its ability to form stable amorphous dispersions and enhance drug solubility, as well as its physicochemical properties, support its role as a key excipient in advanced drug delivery systems. Recent investigations have demonstrated the adaptability of SLP in addressing drug delivery requirements, offering controlled release, improved targeting, and superior therapeutic outcomes. This review examines some key formulation methods that make use of SLP, including hot-melt extrusion, spray drying, electrospinning, drug–polymer layering, and capsule and tablet formulations, highlighting the capacity of SLP to overcome formulation challenges. Biomedical applications of SLP have also been explored, with a focus on its role in improving the delivery of antitumoral, anti-inflammatory, antimicrobial, and antiparasitic drugs. Full article

Background/Objectives: Cilnidipine (CIL) is a calcium channel blocker that exhibits low bioavailability (~13%) due to poor aqueous solubility and extensive pre-systemic gut wall metabolism. The current study aimed to enhance the oral bioavailability of CIL by formulation of polymeric spherical agglomerates (CILSAs)-based orodispersible tablets (ODTs). Methods: Eight different batches of CILSAs were prepared by a crystallo-co-agglomeration technique using different proportions of hydrophilic polymers like hydroxy propyl methyl cellulose E50, polyvinyl pyrrolidone K30, or polyethylene glycol (PEG) 6000 as carriers. Fourier transform infrared spectroscopy (FTIR) of CILSAs proved the chemical integrity of CIL in SAs, while scanning electron microscopy revealed the spherical shape of CILSAs. Results: Differential scanning calorimetry and powder X-ray diffraction studies confirmed that CIL was rendered more amorphous in CILSAs. CILSAs displayed good flow behavior, high percentage yield, and high drug loads. The batch F4 composed of PEG 6000 emerged as the optimized batch as it displayed high percentage dissolution efficiency (57.01 ± 0.01%), which was significantly greater (p < 0.001) compared to CIL (26.27 ± 0.06%). The optimized formulation of CILSAs was directly compressed into ODTs that were rendered porous by vacuum drying. The optimized formulation of porous ODTs (T3) displayed low friability (0.28 ± 0.03%), short disintegration time (6.26 ± 0.29 s), and quicker dissolution (94.16 ± 1.41% in 60 min) as compared to marketed tablet Cildipin^® 10 mg (85 ± 2.3%). Conclusions: Thus, porous ODTs of CILSAs can rapidly release the drug, bypass gut metabolism, enhance oral bioavailability, and improve CIL’s therapeutic effectiveness for angina and hypertension. Full article

High-Density Polyethylene (HDPE) and Low-Density Polyethylene (LDPE) films were used to create nanoplastic (NP) models, with the shape of delamination occurring during degradation. In the case of HDPE, selective degradation occurred not only in the amorphous part, but also in the crystalline part at the same time. Some of the lamellae that extend radially to form the spherulite structure were missing during the 30-day degradation. The length of these defects was less than 1 µm. HDPE disintegrated within units of spherulite structure by conformational defects in lamellae, and the size of the fragments obtained had a wide distribution. LDPE was synthesized by radical polymerization, so it contained a cross-linked part. The part was not sufficiently fused, and when it degraded, it delaminated and separated preferentially. The zeta potential reached a minimum value of approximately −20 mV at the degradation time of 21 days, and then increased. This complex dependence on degradation time was due to NP particle aggregation. The addition of 1% Triton(R) X-114 surfactant was effective in stabilizing the NP dispersion. The particle size remained constant at around 20 nm for degradation times of 15–30 days. Full article

The deformation behavior and instabilities occurring during the drawing of high-density polyethylene (HDPE) were investigated using wide- and small-angle X-ray scattering (WAXS and SAXS) and scanning electron microscopy (SEM) in plain HDPE and paraffin wax- and/or chloroform-modified samples. In contrast to neat HDPE, the modified materials demonstrated strongly suppressed cavitation. However, regardless of cavitation, the tensile deformation of all samples was found to be governed by crystallographic mechanisms active in the crystalline lamellae, supported by shear in the amorphous layers, i.e., the same mechanisms as those operating in other deformation modes. In addition to cavitation, which seems to be a tension-specific phenomenon that does not have a major effect on the deformation sequence, two other important deformation instabilities were observed: microbuckling followed by development of lamellar kinks, at true strain of e = 0.3–0.4, and slip localization instability leading to lamellar fragmentation at e > 0.6. These instabilities were found to be common and very important steps in the deformation sequence, greatly influencing the deformation behavior and occurring in similar strain ranges in both compression and tension, regardless of cavitation. In contrast, cavitation is not able to substitute or significantly modify the main deformation mechanisms, and, furthermore, it does not compete with the main instabilities associated with crystalline lamellae, especially microbuckling; therefore, it may be considered a tension-specific side effect that is not essential for plastic deformation behavior, although it can still significantly affect the final properties and appearance of the drawn material. Full article

This research explores how varying proportions of virgin polyethylene terephthalate (vPET) and recycled polyethylene terephthalate (rPET) in vPET-rPET blends, combined with preform thermal conditions during the stretch blow molding (SBM) process, influence PET bottles’ microscopic characteristics. Key metrics such as viscosity, density, crystallinity, amorphous phase relaxation, and microcavitation were assessed using response surface methodology (RSM). Statistical analysis, including Analysis of variance (ANOVA) and its power, supported the interpretation of results. The first part of the work details the experimental design and statistical methods. Positron annihilation lifetime spectroscopy (PALS) and amorphous phase density analysis revealed reduced free volume size, a substantial increase in free volume quantity, and a transformation toward ellipsoidal geometries, highlighting significant structural changes in the material. At the same time, the intrinsic viscosity (IV) and PALS studies indicate that the solid-state post-condensation effect (SSPC) is linked with microcavitation through post-condensation product diffusion. The conclusions, which resulted from the microstructure analysis, affected the material’s mechanical strength and were validated by pressure resistance tests of the bottles. Full article

In recent years, many studies have focused on improving the bioconversion of cellulose by adding non-ionic surfactants. In our study, the effect of the addition of a polymer, polyethylene glycol (PEG 4000), on the bioconversion of different cellulose materials was evaluated, focusing on the hydrolysis efficiency and structural changes in pure cellulose after the enzymatic hydrolysis process. The obtained results showed that the addition of non-ionic surfactant significantly improved the digestibility of cellulosic materials. The highest hydrolysis efficiency was observed for Sigmacel 101 (Cel-S101) cellulose, which consists mainly of amorphous regions. In the case of Avicel cellulose (Cel-A), PEG had a lesser effect on the bioconversion’s efficiency due to limited access to the crystal structure and limited substrate–cellulase interactions. The consistency of the obtained results is confirmed by qualitative and quantitative analyses (XRD, FTIR, and HPLC). Our findings may be helpful in further understanding the mechanism of the action of surfactants and improving the enzymatic hydrolysis process. Full article

Dehydration is the principal conservation process for waterlogged archaeological wood (WAW), with the aim of preventing shrinkage and cracking. For well-preserved WAW, shrinkage mainly takes place when the moisture content is below the fiber saturation point. Here, we conduct a new trial using ionic liquid as a dimensional stabilizer to maintain a stable swollen state of WAW. Molecular dynamics simulation (MD), shrinkage measurement, Fourier transform infrared spectroscopy (FTIR), and dynamic vapor sorption (DVS) were adopted to investigate the interactions and effects of 1-Butyl-3-methylimidazolium chloride ([Bmim][Cl]) on WAW (Dipterocarpaceae Dipterocarpus sp. with a maximum moisture content of 80.3%) in comparison with the conventional material polyethylene glycol (PEG). The results show that [Bmim][Cl] and its water mixtures have a comparable or slightly greater ability to swell amorphous cellulose than does water at room temperature, while crystalline cellulose is left intact. The samples treated with [Bmim][Cl] show less shrinkage than the PEG 300- and PEG 2000-treated samples at all tested concentrations after air-drying. The best dimension control was achieved by 40 wt% [Bmim][Cl], with volumetric shrinkage reduced from 5.03% to 0.47%. DVS analysis reveals that [Bmim][Cl] reduces moisture contents at moderate and low relative humidity (<80%) when the concentration is at or below 20 wt%, which suggests that good dimensional stability was not achieved by simply preserving the moisture content but possibly through the interaction of the ionic liquid with the wood polymers. Full article

This study successfully developed edible films with excellent mechanical strength and notable water resistance, utilizing curdlan (CL) as the primary matrix and incorporating various plasticizers, including glycerol (GLY), ethylene glycol (EG), propylene glycol (PRO), xylitol (XY), sorbitol (SOR), and polyethylene glycol (PEG). A comprehensive suite of analytical techniques, including Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), and tensile testing, were employed to evaluate the films’ structural and mechanical properties. After incorporating PEG, the water sensitivity increased slightly, with a contact angle (CA) of 97.6°, and a water solubility (WS) of 18.75%. The inclusion of plasticizers altered the crystalline structure of the CL matrix, smoothing and flattening the film surface while reducing hydrogen-bonding interactions. These structural changes led to a more uniform distribution of amorphous chain segments and a decrease in glass transition temperatures. Among the tested plasticizers, GLY exhibited the highest compatibility with CL, resulting in the smoothest surface morphology and delivering the most effective plasticizing effect. The CL-GLY film showed a dramatic improvement in flexibility, with an elongation at break that was 5.2 times higher than that of the unplasticized film (increasing from 5.39% to 33.14%), indicating significant enhancement in extensibility. Overall, these findings highlight the potential of CL-GLY films as sustainable and effective materials for food packaging applications. Full article

Bamboo is widely distributed around the world as an excellent renewable resource. However, the structural and morphological changes in the bamboo samples in extracting bamboo cellulose fiber using alkaline-acidic sodium chlorite are unclear, and the potential for preparation of cellulose packaging films is yet to be explored. In this paper, the changes in micro-morphology, chemical structure, and pyrolytic behavior of moso bamboo powder during alkaline and acidic sodium chlorite pretreatment were intensively investigated. The bamboo cellulose fiber (BC) diameter decreased from 14.41 to 11.79 µm with the treatment as a result of the removal of amorphous materials such as lignin and hemicellulose. The BC was dissolved in NaOH/urea aqueous solution, and all-cellulose composite films were obtained with excellent mechanical properties and high transparency. When the BC contents reached 4 wt%, the resulting films had a light transmittance of about 90% in the visible light range (400–780 nm), and the tensile strength was as high as 57.9 MPa, which was much higher than that of the polyethylene packaging film (PE, 35 MPa). In addition, the film also suggests superior biodegradability compared to PE films. Therefore, the current shortage of raw materials and environmental pollution faced by plastic packaging materials may be expected to gain new inspiration in this study. Full article