Search Results (411)

A review of the literature on polymorphic transformations by milling on pharmaceutical materials was carried out. The available information on 18 pharmaceutical materials was compiled. In particular, when data are available, the starting and final crystalline forms, their enantiotropic or monotropic relationship, the glass transition temperature of the compound and its melting temperature, the experimental observation of a transient or partial amorphization of compounds, and the transformation kinetics make it possible to suggest a two-step transformation mechanism. First, an amorphization occurs under milling of the starting polymorphic form. Secondly, a recrystallization of the amorphous form occurs towards the final form. The observed transformation kinetics are due to the fact that the recrystallization of the amorphous material towards the final form depends on the accidental formation of a cluster of this form during milling. Moreover, the observation of the transient amorphous form depends on the relative position of the glass transition temperature of the material with respect to the milling temperature. This mechanism seems to be independent of the enantiotropic or monotropic character of the polymorphic forms involved in the transformation. Full article

The role and performance of desert sand in alkali-activated mortar remain insufficiently understood. To address this knowledge gap, this study systematically investigates the fluidity, mechanical properties, and microscopic morphology of alkali-activated mortar with varying desert sand substitution rates (DSRR, 0–100%). The key findings reveal that a low DSRR (10–20%) enhances mortar fluidity and reduces drying shrinkage, though at the cost of reduced compressive strength. At 40% DSRR, the mortar exhibits elevated porosity (12.3%) and diminished compressive strength (63 MPa). Notably, complete substitution (100% DSRR) yields a well-structured matrix with optimized pore distribution, characterized by abundant gel micropores, and achieves a compressive strength of 76 MPa. These results demonstrate that desert sand can fully replace river sand in alkali-activated mortar formulations without compromising performance. Microstructural analysis confirms that desert sand actively participates in the alkali activation process. Specifically, the increased Ca²⁺ content facilitates the transformation of amorphous gels into crystalline phases. It also found that desert sand could make the fly ash more soluble, affecting the alkali activation reaction. Full article

The extensive accumulation of plastic waste causes serious environmental problems, leading to growing interest in biodegradable alternatives. In this study, the structural, chemical, and crystalline characteristics of a pulp-based material incorporating sugarcane bagasse ash (SCBA) were investigated using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Mechanical properties of the materials were investigated through compression, tensile, and bending tests in order to assess their strength and flexibility, while biodegradability was evaluated through soil burial tests. The results indicate that SCBA addition enhances compressive strength, with optimal performance obtained at 15% SCBA content, while tensile and bending strengths showed an enhancement at 5% content. FTIR and XRD analyses suggested an increase in amorphous regions and notable microstructural interactions between SCBA particles and cellulose fibers, particularly at a 10% concentration. SEM images further confirmed effective particle dispersion and improved porosity in the composite materials. Furthermore, samples incorporating SCBA exhibited superior biodegradability compared to pure pulp. Overall, these findings highlight that incorporating 10–15% SCBA provides a promising balance between mechanical integrity and environmental sustainability, offering a viable strategy for developing eco-friendly, high-performance packaging materials. Full article

Polypropylene (PP), with its good physical, thermal, and mechanical properties and excellent processing capabilities, has become one of the most used synthetic polymers. It is known that the overall properties of semicrystalline polymers, including PP, are governed by morphology, which is influenced by the crystallization behavior of the polymer under specific conditions. The most important industrial PP remains the isotactic one, and it has been studied extensively for its polymorphic characteristics and crystallization behavior for over half a century. Due to its regular chain structure, isotactic polypropylene (iPP) belongs to the group of polymers with a high tendency for crystallization. The rapid quenching of molten iPP fails to produce a completely amorphous polymer but leads to an intermediate crystalline order. On the other hand, slow cooling yields a material with high crystalline content. The processing conditions that occur in practice and industry are between these two extremes and, in some cases, are even very close. Therefore, the study of limits in processability and the impact of extreme preparation conditions on morphology, structure, thermal, and mechanical properties fills a gap in the current understanding of how the processing conditions of iPP can be used to design the desired properties for specific applications and is in the focus of this research. The first set of samples (Q samples) was obtained by rapid quenching, while the second was prepared by very slow cooling from the melt to room temperature (SC samples). Testing of samples was performed by optical microscopy (OM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic dielectric spectroscopy (DDS), and mechanical measurements. Characterization revealed that slowly cooled samples exhibited a significantly higher degree of crystallinity and larger crystallites (χ ≥ 55% and L₍₁₁₀₎ ≈ 20 nm), compared to quenched samples (χ < 30%, L₍₁₁₀₎ ≤ 3 nm). Mechanical testing showed a drastic contrast: quenched samples exhibited elongation at break > 500%, while slowly cooled samples broke below 15%, reflecting their brittle behavior. For the first time, DDS is applied to investigate molecular mobility differences between processing-dependent structural forms, specifically the mesomorphic (smectic) and α-monoclinic forms. In slowly cooled samples, α relaxation exhibited both enhanced intensity and an upward temperature shift, indicating stronger structural constraints due to a much higher crystalline phase content and significantly larger crystallite size, respectively. These findings provide novel insights into the structure–property–processing relationship, which is crucial for industrial applications. Full article

This study investigates the dynamic operation of a pilot-scale precipitation reactor designed to produce oxygenated phosphocalcium apatites with controlled composition and low crystallinity, closely mimicking the mineral phase of bone. Our approach is based on integrating kinetic monitoring and dynamic reactor control to direct the formation of apatites with tailored structural and chemical properties. Three synthesis routes were explored using CaCO₃, Ca(NO₃)₂, and CaCl₂ as calcium precursors, under optimized Ca/P molar ratios. The evolution of ionic concentrations (Ca²⁺, PO₄³⁻), peroxide and molecular oxygen incorporation, and carbonate content was monitored over a reaction time range of 2 min to 4 h. Characterization by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and chemical analysis revealed a time-dependent transformation of amorphous phases into poorly crystalline apatites with specific textures. After 60 min, the Ca/P atomic ratio stabilized at approximately 1.575, and the resulting apatites exhibited structural features comparable to those of human bone. This study highlights the influence of reactor operation time on precipitation kinetics and the properties of bioactive apatites in a scalable system. The results offer promising prospects for the large-scale production of bone-mimetic materials. However, the lack of biological validation remains a limitation. Future studies will assess the cytocompatibility and bioactivity of these materials to confirm their potential for biomedical applications. Full article

This work investigated the structural response and phase transformation dynamics of silica-bearing cherts subjected to high-temperature processing (up to 1400 °C) and prolonged mechanochemical activation. Through a combination of X-ray diffraction (XRD) with Rietveld refinement, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and transmission electron microscopy (HRTEM), we trace the crystallographic pathways of quartz, moganite, tridymite, and cristobalite under controlled thermal and mechanical stress regimes. The experimental results demonstrated that phase behavior is highly dependent on intrinsic properties such as initial phase composition, impurity presence, and crystallinity. Heating at 1400 °C induced irreversible conversion of quartz, moganite, and tridymite into cristobalite. Samples enriched in cristobalite and tridymite exhibited notable increases in crystallinity, whereas quartz-dominant samples showed either stability or a decline in structural order. Rietveld analyses underscored the critical influence of microstrain and crystallite size on thermal resilience and phase persistence. Thermal profiles revealed by DSC and TGA expose overlapping processes including polymorphic transitions, minor phase dehydration, and redox-driven changes, likely associated with trace components. Mechanochemical processing resulted in partial amorphization and the emergence of phases such as opal and feldspar minerals (microcline, albite, anorthite), interpreted as the product of lattice collapse and subsequent reprecipitation. Heat treatment of chert leads to a progressive rearrangement and recrystallization of its silica phases: quartz collapses around 1000 °C before recovering, tridymite emerges as an intermediate phase, and cristobalite shows the greatest crystallite size growth and least deformation at 1400 °C. These phase changes serve as markers of high-temperature exposure, guiding the identification of heat-altered lithic artefacts, reconstructing geological and diagenetic histories, and allowing engineers to adjust the thermal expansion of ceramic materials. Mechanochemical results provide new insights into the physicochemical evolution of metastable silica systems and offer valuable implications for the design and thermal conditioning of silica-based functional materials used in high-temperature ceramics, glasses, and refractory applications. From a geoarchaeological standpoint, the mechanochemically treated material could simulate natural weathering of prehistoric chert tools, providing insights into diagenetic pathways and lithic degradation processes. Full article

A novel bioactive glass–ceramic was developed using biogenic hydroxyapatite (BHA) synthesized from Rapana venosa (Black Sea) shells and monocalcium phosphate monohydrate [Ca(H₂PO₄)₂·H₂O] via solid-state synthesis. The prepared batches were obtained by combining BHA with SiO₂, B₂O₃, and Na₂O, melted at 1200 °C and melt-quenched in water to form glass–ceramic materials. Dense biogenic hydroxyapatite-based ceramics were successfully sintered at 1200 °C (2 h hold) using a 25 mass % sintering additive composed of 35 mass % B₂O₃, 45 mass % SiO₂, 10 mass % Al₂O₃, and 10 mass % Na₂O. Structural characterization was carried out using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The resulting materials consisted of a well-defined crystalline hydroxyapatite phase [Ca₁₀(PO₄)₆(OH)₂] alongside an amorphous phase. In samples with increased SiO₂ and reduced B₂O₃ content (composition 3), a finely dispersed Na₃Ca₆(PO₄)₅ crystalline phase appeared, with a reduced presence of hydroxyapatite. Bioactivity was assessed in simulated body fluid (SBF) after 10 and 20 days of immersion, confirming the material’s ability to support apatite layer formation. The main structural units SiO₄, PO₄, and BO₃ are interconnected through Si–O–Si, B–O–B, P–O–P, and mixed Si–O–Al linkages, contributing to both structural stability and bioactivity. Full article

Background/Objectives: Chronic lung diseases are among the leading causes of death worldwide. In the treatment of these diseases, non-steroidal anti-inflammatory drugs can be effective. We have previously developed an excipient formulation alongside a modern manufacturing protocol, which we aim to further investigate. We have chosen two new model drugs, meloxicam (MX) and its water-soluble salt, meloxicam-potassium (MXP). The particles in dry powder inhaler (DPI) formulation were expected to have a spherical shape, fast drug release, and good aerodynamic properties. Methods: The excipients were poloxamer-188, mannitol, and leucine. The samples were prepared by spray drying, preceded by solution preparation and wet grinding. Particle size was determined by laser diffraction, shape by scanning electron microscopy (SEM), crystallinity by powder X-ray diffraction (PXRD), interactions by Fourier-transform infrared spectroscopy (FT-IR), in vitro drug dissolution by paddle apparatus, and in vitro aerodynamic properties by Andersen cascade impactor and Spraytec^® device. Results: We achieved the proper particle size (<5 μm) and spherical shape according to laser diffraction and SEM. The XRPD showed partial amorphization. FT-IR revealed no interaction between the materials. During the in vitro dissolution tests, more than 90% of MX and MXP were released within the first 5 min. The best products exhibited an aerodynamic diameter of around 4 µm, a fine particle fraction around 50%, and an emitted fraction over 95%. The analysis by Spraytec^® supported the suitability for lung targeting. Conclusions: The developed preparation process and excipient system can be applied in the development of different drugs containing DPIs. Full article

In response to escalating global energy demands and environmental challenges, electrochromic (EC) smart windows have emerged as a transformative technology for adaptive solar modulation. Herein, we report the rational design and fabrication of a bilayer WO₃/TiO₂ heterostructure via a synergistic two-step strategy involving the electrochemical deposition of amorphous WO₃ and the controlled hydrothermal crystallization of TiO₂. Structural and morphological analyses confirm the formation of phase-pure heterostructures with a tunable TiO₂ crystallinity governed by reaction time. The optimized WTi-5 configuration exhibits a hierarchically organized nanostructure that couples the fast ion intercalation dynamics of amorphous WO₃ with the interfacial stability and electrochemical modulation capability of crystalline TiO₂. Electrochromic characterization reveals pronounced redox activity, a high charge reversibility (98.48%), and superior coloration efficiency (128.93 cm²/C). Optical analysis confirms an exceptional transmittance modulation (ΔT = 82.16% at 600 nm) and rapid switching kinetics (coloration/bleaching times of 15.4 s and 6.2 s, respectively). A large-area EC device constructed with the WTi-5 electrode delivers durable performance, with only a 3.13% degradation over extended cycling. This study establishes interface-engineered WO₃/TiO₂ bilayers as a scalable platform for next-generation smart windows, highlighting the pivotal role of a heterostructure design in uniting a high contrast, speed, and longevity within a single EC architecture. Full article

The starch modification of mango cotyledons with both single ultrasound (US) and dual (US followed by octenyl succinic anhydride, OSA) was optimized by response surface methodology (RSM). The mechanochemical effects of ultrasound on amylose content, particle size, and dual modification efficiency were assessed. In addition, the structural, thermal, morphological, and functional properties were evaluated. After optimization with single US (41 min and 91% sonication intensity), sonication induced starch granule fragmentation, altering amorphous and partially crystalline regions, which increased amylose content (34%), reduced particle size (Dx50 = 12 μm), and modified granule surface morphology. The dual modification (the subsequent OSA reaction lasted 4.6 h under the same conditions) reached a degree of substitution of 0.02 and 81% efficiency, imparting amphiphilic properties to the starch. OSA groups were mainly incorporated into amorphous and surface regions, which decreased crystallinity, gelatinization temperature, and enthalpy. The synergistic effect of the modification with US and OSA in the dual modification significantly improved the solubility and swelling power of starch, resulting in better dispersion, functionality in aqueous systems, and chemical reactivity. These findings highlight the potential of dual modification to transform mango cotyledon starch into a versatile ingredient in the food industry as a thickener, a stabilizer in soups and sauces, an emulsifier, a carrier of bioactive and edible films; in the cosmetic industry as a gelling and absorbent agent; and in the pharmaceutical industry for the controlled release of drugs. Furthermore, valorizing mango cotyledons supports circular economy principles, promoting sustainable and value-added food product development. Full article

With the growing integration of electronic systems into modern infrastructure, the need for effective electromagnetic interference (EMI) shielding materials has intensified. This study explores the development of electroless Ni-plated fiber composites and systematically investigates the effects of post-heat treatment on their electrical, structural, and interfacial performance. Both carbon fibers (CFs) and glass fibers (GFs) were employed as reinforcing substrates, chosen for their distinct mechanical and thermal characteristics. Ni plating enhanced the electrical conductivity of both fibers, and heat treatment facilitated phase transformations from amorphous to crystalline Ni₃P and Ni₂P, leading to improved EMI shielding effectiveness (EMI-SE). NGF-based composites achieved up to a 169% increase in conductivity and a 116% enhancement in EMI-SE after treatment at 400 °C, while NCF-based composites treated at 800 °C attained superior conductivity and shielding performance. However, thermal degradation and reduced interfacial shear strength (IFSS) were observed, particularly in GF-based systems. The findings highlight the importance of material-specific thermal processing to balance functional performance and structural reliability. This study provides critical insights for designing fiber-reinforced composites with optimized EMI shielding properties for application-driven use in next-generation construction materials and intelligent infrastructure. Full article

Vegetal sources are a continuous research field and different types of extracts have been obtained over time. The most challenging part is compounding them in a pharmaceutical product. This study aimed to integrate a mixture (EX) of four extracts (SE-Sophorae flos, GE-Ginkgo bilobae folium, ME-Meliloti herba, CE-Calendulae flos) in formulations with polymers (polyhydroxybutyrate, polylactic-co-glycolic acid) and their physicochemical profiling. The resulting samples consist of particle suspensions, which were subjected to Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy analysis. When compared to single-extract formulations spectra, they revealed band changes, depending on the complex interactions. Using X-ray Diffractometry, the partially crystalline phase was highlighted for EX-PLGA, while the others were amorphous. Moreover, Atomic Force Microscopy pointed out the nanoscale particles and the topography of the samples, and the outstanding roughness belonging to EX-PHB-PLGA. A 30 min period of immersion was enough for the formulations to spread on the surface of the compression stockings material (CS) and after drying, it became a polymeric film. TGA analysis was performed, which evaluated the impregnated content: 5.9% CS-EX-PHB, 6.4% CS-EX-PLGA, and 7.5% CS-EX-PHB-PLGA. In conclusion, the extract’s phytochemicals and the interactions established with the polymers or with the other extracts from the mixture have a significant impact on the physicochemical properties of the obtained formulations, which are particularly important in pharmaceutical product development. Full article

Thin films of bismuth(III) sulfide (Bi₂S₃) on fluorine doped tin oxide (FTO) coated glass slides were successfully formed by the chemical bath deposition (CBD) method. In this work, a new sulfur precursor L-cysteine was used instead of the typical sulfur precursors, such as urea, thiosulfate, or thioacetamide, used for the formation of the Bi₂S₃ films by the CBD method. The synthesized Bi₂S₃ thin film on the FTO substrate was subjected to characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and UV–Visible spectroscopy analysis. An X-ray diffraction analysis showed that, initially, Bi₂S₃ films of an amorphous structure with elemental sulfur impurities were formed on the FTO surface. During the annealing of the samples, amorphous Bi₂S₃ was transformed into its crystalline phase with an average crystallite size of about 22.06 nm. The EDS studies confirmed that some of the sulfur that was not part of the Bi₂S₃ was removed from the films during annealing. The influence of the morphology of Bi₂S₃ films on their optical properties was confirmed by studies in the UV-visible range. Full article

Nanomilling-driven effects on polyamorphic transitions are examined in tetra-arsenic biselenide As₄Se₂ alloy, which is at the boundary of the glass-forming region in the As-Se system, using multifrequency temperature-modulated DSC-TOPEM^® technique, supported by X-ray powder diffraction (XRPD) and micro-Raman spectroscopy analysis. As shown by XRPD analysis, this alloy reveals a glassy–crystalline nature due to rhombohedral As and cubic As₂O₃ (arsenolite) inclusions, which especially grew after milling in a PVP (polyvinylpyrrolidone) water solution. At the medium-range structure level, nanomilling-driven changes are revealed as the disruption of intermediate-range ordering and enhancement of extended-range ordering. The generalized molecular-to-network amorphization trend in this alloy is confirmed by the microstructure response revealed in the broadened and obscured features in micro-Raman scattering spectra collected for nanomilled specimens. Thermophysical heat-transfer phenomena are defined by molecular-to-network polyamorphic transformations activated under nanomilling. The domination of thioarsenide-type As₄Se_n entities in this alloy results in an abnormous nanomilling-driven network-enhanced glass transition temperature increase. The nanomilled alloys become notably stressed owing to the destruction of molecular thioarsenide and incorporation of their remnants into the newly polymerized arsenoselenide network. This effect is more pronounced in As₄Se₂ alloy subjected to dry nanomilling, while it is partly counterbalanced when this alloy is additionally subjected to wet milling in a PVP water solution, accompanied by the stabilization of the As₄Se₂/PVP nanocomposite. Full article

Background/Objectives: Rivaroxaban, an oral anticoagulant, shows poor aqueous solubility, posing significant challenges to its bioavailability and therapeutic efficiency. The present study investigates the improvement of rivaroxaban’s solubility through the formation of different inclusion complexes with three cyclodextrin derivatives, such as β-cyclodextrin (β-CD), methyl-β-cyclodextrin (Me-β-CD), and hydroxypropyl-β-cyclodextrin (HP-β-CD) prepared by lyophilization in order to stabilize the complexes and improve dissolution characteristics of rivaroxaban. Methods: The physicochemical properties of the individual compounds and the three lyophilized complexes were analysed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Results: FTIR spectra confirmed the formation of non-covalent interactions between rivaroxaban and the cyclodextrins, suggesting successful encapsulation into cyclodextrin cavity. SEM images revealed a significant morphological transformation from the crystalline structure of pure rivaroxaban and cyclodextrins morphologies to a more porous and amorphous matrix in all lyophilized complexes. XRD patterns indicated a noticeable reduction in drug crystallinity, supporting enhanced potential of the drug solubility. TGA analysis demonstrated improved thermal stability in the inclusion complexes compared to the individual drug and cyclodextrins. Pharmacotechnical evaluation revealed that the obtained formulations (by comparison with physical mixtures formulations) possessed favorable bulk and tapped density values, suitable compressibility index, and good flow properties, making all suitable for direct compression into solid dosage forms. Conclusions: The improved cyclodextrins formulation characteristics, combined with enhanced dissolution profiles of rivaroxaban comparable to commercial Xarelto^® 10 mg, highlight the potential of both cyclodextrin inclusion and lyophilization technique as synergistic strategies for enhancing the solubility and drug release of rivaroxaban. Full article