Mechanochemical modification and synthesis of drugs

Various aspects of the application of mechanochemistry and mechanical activation in the study of pharmaceutical materials are presented including the use of mechanical activation for modification of the physical and chemical properties of drugs and solid state synthesis of the drugs by mechanochemical methods. It is necessary to take the mechanochemical factors into account during grinding and tabletting the drugs.     

聚合物力化学理论及应用进展

综述了聚合物力化学的基本理论研究和聚合物合成方面的应用研究,阐述了聚合物在力场作用下的降解及聚合机理,介绍了力化学进行聚合物合成和改性的特点及优势。     

Mechanochemistry: Toward green synthesis of metal–organic frameworks

Metal–organic frameworks (MOFs) have attracted a special attention due to outstanding porosity, adjustable pore sizes, and huge opportunities in varying organic–inorganic compositions. Enormous studies conducted so far on MOFs indicate their high potential in catalysis, gas adsorption, drug delivery, water treatment, energy storage, among others. However, mass production of MOFs is still limited mainly due to the non-economic, non-green and complex synthesis methods. Mechanochemistry is an alternative solution for efficient and environmentally friendly syntheses of various MOFs. Fast and solvent-free or solvent-less mechanosynthesis seems to be a very powerful versatile method for obtaining these advanced porous materials. The mechanochemical concept was used for the preparation of various MOFs including the most popular structures: MOF-5, ZIF-8, HKUST-1, MIL-101, UiO-66. These MOFs feature high specific surface areas, comparable to those prepared by conventional solvent-based methods. Furthermore, mechanochemistry was successfully used for the synthesis of non-conventional multimetallic MOFs and previously unreported solid phases. This review shows the recent developments, challenges and perspectives of green synthesis of diverse MOF structures using mechanochemistry. Besides describing the mechanochemical synthesis of MOFs, some achievements in green applications are also summarized. Importantly, current trends in research suggests for further development of these fields i.e., harmful gas adsorption, water treatment, and energy storage.     

Mechanochemical Approaches to Fullerene Chemistry

The efficiency of the utilization of mechanical activation, a non-conventional form of energy, is discussed in the framework of the development of the fields of mechanochemistry and fullerene chemistry. It is applied to processes taking place within solid phases as a consequence of the influence of mechanical energy. Various types of mechanochemical syntheses of fullerene compounds are described.     

Mechanochemistry of sulphides

At present mechanochemistry of sulphides appears to be a science with sound theoretical foundation exhibiting a wide range of opportunities in different area of science and technology. For traditional applicationsmechanochemistry is of exceptional importance in mineral processing and extractive metallurgy. Mineral disordering by high energy milling has a positive influence on the reaction kinetics and further phenomena, such as changing the reaction mechanism to reduce environmental impacts. Metal sulphides can be utilized nowadays, in advanced applications such as precursors for synthesis of high temperature superconductors, luminescent and solar energy materials, high-energy density batteries and further materials for opto-electronic and magnetic applications. Mechanochemistry in this case serves as a tool which can effectively control and regulate the solid state reactions for advanced materials preparation. It is aim of this review paper to illustrate the progress in mechanochemistry of sulphides achieved in recent years in Slovakia.     

无铅压电陶瓷粉体的制备和晶粒定向生长技术

材料体系及其制备技术是新材料研究中的两个重要内容.从无铅压电陶瓷的粉体制备和晶粒定向生长两方面介绍了无铅压电陶瓷的制备技术研究(如机械化学法、溶胶-凝胶法、反应模板晶粒生长技术等)及其进展,并分析了各种制备方法的优缺点.     

机械力化学合成纳米晶体的研究

介绍了机械力化学的概念、作用机理及其表征技术。阐述了机械力化学制备纳米粉体的机理和优越性,并主要以BaTiO3纳米晶为例,研究其合成方法及反应机制。对其未来发展进行了展望。     

Mechanochemical synthesis of ternary chalcogenide chalcostibite CuSbS2 and its characterization

Journal of Materials Science: Materials in Electronics - In this work, the very rapid one-step mechanochemical synthesis of nanocrystalline ternary chalcogenide chalcostibite CuSbS2 prepared from...     

长波红外光学材料的研究进展

红外光学材料是红外技术应用的基础之一. 适用于8～12μm波段的长波红外光学材料具有广阔的应用前景. 本文介绍了几类常用的长波红外光学材料的基本性质, 简述了其制备技术及发展现状, 讨论了它们各自存在的问题. 文章指出未来研究重点在于复合型红外光学材料的设计和制备, 大尺寸II-VI族化合物单晶的生长, 碱卤化合物晶体保护膜技术以及新型硫系玻璃的开发.     

Progress in synthesis of ferroelectric ceramic materials via high-energy mechanochemical technique

Ferroelectric ceramics are important electronic materials that have a wide range of industrial and commercial applications, such as high-dielectric constant capacitors, piezoelectric sonar or ultrasonic transducers, pyroelectric security sensors, medical diagnostic transducers, electro-optical light valves, and ultrasonic motors, to name a few. The performances of ferroelectrics are closely related to the ways they are processed. The conventional solid state reaction method requires high calcination and sintering temperatures, resulting in the loss of lead, bismuth or lithium components due to their high volatilities, thus worsening the microstructural and subsequently the electrical properties of the ferroelectric materials. Various wet chemistry based routes have been developed to synthesize ultra-fine and even nano-sized ferroelectric powders. However, most of the chemistry based routes still involve calcinations, although at relatively lower temperatures. High energy mechanochemical milling process has been shown that some ferroelectric materials can be synthesized directly from their oxide precursors in the form of nano-sized powders, without the need for the calcination at intermediate temperatures, thus making the process very simple and cost-effective. A large number of ferroelectric materials, including lead-containing ferroelectrics, antiferroelectrics and relaxors, and bismuth-containing Aurivillius families, have been synthesized by the high-energy milling process. Some ferroelectrics, such as barium titanate (BaTiO₃ or BT), lead iron tungstate [Pb(Fe_2/3W_1/3)O₃ or PFW], and several bismuth-containing materials, that cannot be directly produced from their oxide mixtures, have been formed at relatively low temperature after their precursors are activated by an high-energy milling. Ferroelectric ceramics derived from the activated precursors demonstrated better microstructure and electrical properties than those without mechanochemical treatment. This review presents an overview of the recent progress in the synthesis of ferroelectric ceramic powders using various high-energy milling techniques. The progress includes several aspects: (i) direct synthesis of nano-sized powders with better sinterability, (ii) promoted reactive sintering due to the modification of the precursors, (iii) amorphization of the precursors, and (iv) refinement of the precursors with high homogeneity. The underlying mechanisms of mechanochemical synthesis of ferroelectric materials are discussed. Further research emphasizes on issues related to the synthesis of ferroelectric ceramic powders are suggested.     

High-purity chalcogenide glasses for fiber optics

The data on the present degree of purity of chalcogenide glasses for fiber optics, on their methods of production and on the properties, which are essential for their actual application, are generalized. The content of limiting impurities in the best samples of chalcogenide glasses is 10–100 ppb wt.; of heterophase inclusions with size of about 100 nm is less than 10³ cm^?3. On the basis of chalcogenide glasses the multimode and single mode optical fibers are produced with technical and operation characteristics sufficient for a number of actual applications. The minimum optical losses of 12–14 dB/km at 3–5 µm are attained in the optical fiber from arsenic-sulfide glass. The level of losses in standard chalcogenide optical fibers is 50–300 dB/km in 2–9 µm spectral range. The factors, affecting the optical absorption of glasses and optical fibers, are analyzed, and the main directions in further development of chalcogenide glasses as the materials for fiber optics are considered.     

Synthesis of 2D Metal Chalcogenide Thin Films through the Process Involving Solution‐Phase Deposition

2D metal chalcogenide thin films have recently attracted considerable attention owing to their unique physicochemical properties and great potential in a variety of applications. Synthesis of large‐area 2D metal chalcogenide thin films in controllable ways remains a key challenge in this research field. Recently, the solution‐based synthesis of 2D metal chalcogenide thin films has emerged as an alternative approach to vacuum‐based synthesis because it is relatively simple and easy to scale up for high‐throughput production. In addition, solution‐based thin films open new opportunities that cannot be achieved from vacuum‐based thin films. Here, a comprehensive summary regarding the basic structures and properties of different types of 2D metal chalcogenides, the mechanistic details of the chemical reactions in the synthesis of the metal chalcogenide thin films, recent successes in the synthesis by different reaction approaches, and the applications and potential uses is provided. In the last perspective section, the technical challenges to be overcome and the future research directions in the solution‐based synthesis of 2D metal chalcogenides are discussed.     

The mechanochemical processing of aerospace metals

The status of mechanochemical processing of aerospace metals (aluminum and titanium) is reviewed. It is demonstrated that the activation of chemical reactions by mechanical energy can lead to many interesting applications including production of advanced materials with novel constitutional and microstructural effects leading to enhanced mechanical properties.     

研磨对室温固相反应制备超细CeO2颗粒的影响

分别采用手工研磨法和湿固相机械球磨法制备CeO2粉末。通过改善室温固相反应中反应物的接触情况,以增加有利于反应的缺陷浓度,改善了反应的热力学和动力学条件,使室温下的固相反应得以进行。产物用SEM进行表征。由于机械作用可使反应物和反应产物的晶体受破坏而细化,同时,反应原料之间的机械化学反应出可促进这一细化过程,结果表明湿固相机械球磨法简便易行,煅烧产物粒径小,且分布均匀。最后讨论了这两种研磨方式对产物粒径大小的影响机理。     

Two important periods in the history of mechanochemistry

Some form of mechanochemical experience has existed from fine grinding of materials since prehistoric times, yet the first systematic investigations on the chemical effects of mechanical action were carried out only at the end of the nineteenth century. Walthére Spring studied the consolidation and reactions of powdered materials due to high pressure at the University of Liège, in order to understand the formation of minerals in the earth’s crust and M. Carey Lea carried out experiments on the decomposition of compounds by grinding in a mortar. In some of his experiments mechanical action produced distinctly different result from the effect of heat. The first part of this paper compares the circumstances and results of Spring and Lea. The other important period in the history of mechanochemistry was the 1960s, the time when the first dedicated conferences were organized and a broader community of mechanochemists formed. This happened in the Soviet Union and Eastern Europe where several groups were working on subjects related to mechanochemistry. In 1968, the first dedicated conference was organized as a special session of the yearly meeting of Soviet colloid chemists. An attempt is made to reconstruct the circumstances leading to that event and the roles played by Rebinder and Thiessen in bringing it together. The next conference on mechanochemistry was already a separate event and it started a yearly series. Extensions have led to the INCOME conferences, including this one in Ko?ice in 2017.     

Magnetic Semiconducting Chalcogenide Spinels: Preparation and Physical Chemistry

Systematic crystal-chemical studies of chalcogenide spinels and related phases are used to develop a novel, unified approach to analyzing the nonstoichiometry of close-packed phases in the series atacamite–spinel–halite with allowance for alternatively occupied tetrahedral and octahedral nonatacamite sites. The main physicochemical approaches to the synthesis and crystal growth of magnetic semiconducting chalcogenide spinels are considered. The phase diagrams of systems containing magnetic semiconducting phases are mapped out. To choose flux growth conditions, the liquidus relations in spinel–solvent systems and the kinetics of mass transport in chemical vapor transport systems are investigated. The influence of high temperatures and pressures on the structure of polycrystalline chalcogenide spinels is analyzed. The purity of the starting materials is shown to have a significant effect on the physical properties of chalcogenide spinels. Physical property measurements demonstrate that the magnetic semiconducting chalcogenide spinels have considerable potential for practical application.     

Synthesis and features of binary cobaltite spinels

The main developments in the synthesis of cobaltites are surveyed. Solid state reactions between oxides, thermal decomposition of mechanical mixtures of transition metal salts, the use of complex compounds as precursors, mechanochemical synthesis, deposition of cobaltites on supports and cobaltite synthesis by thermal treatment of coprecipitated compounds are discussed and the specific advantages and disadvantages of each method pointed out. The binary spinel cobaltites find applications as materials in many fields, their main importance being as catalysts. In order to achieve high specific surface area, cobaltite synthesis by thermal treatment of coprecipitated precursors proves to be the most promising method. Different kinds of precursors are regarded. Transition metal basic salts are promising for the synthesis of binary mixed oxides and, in particular, of cobaltites. The conditions suited by the coprecipitated precursors for the synthesis of cobaltites with preset properties, such as high-dispersity, homogeneity, a definite stoichiometry and a low impurity content, are indicated. Special attention is paid to hydroxidecarbonates. Their use as precursors ensures these demands for the final product and also evolution of toxic gases during the thermal decomposition is avoided.     

Mechanochemical synthesis of nanoparticles

The results of recent investigation of the mechanochemical synthesis of inorganic nanoparticles are reviewed. It was demonstrated that, by selecting suitable chemical reaction paths, stoichiometry of starting materials and milling conditions, mechanochemical processing can be used to synthesise a wide range of nanocrystalline particles dispersed within a soluble salt matrix. Selective removal of the matrix phase by washing the resulting powder with appropriate solvents can yield nanoparticles of the desired phase. This technique has been shown to have advantages over other methods of producing nanoparticles in terms of low cost, small particle sizes, low agglomeration, narrow size distributions and uniformity of crystal structure and morphology.     

Mechanochemical Synthesis and SHS of Diborides of Titanium and Zirconium

Some properties of titanium diboride (TiB₂) obtained by explosive mechanochemical synthesis and self-propagated high-temperature synthesis (SHS) have been investigated. The properties of zirconium diboride (ZrB₂) obtained by SHS have also been studied. There is a general opinion that explosive mechanochemical synthesis proceeds by a SHS mechanism. For that reason, it is of interest to compare the properties of a product synthesized from the same reagents, by both mechanochemical synthesis and SHS. In order to elucidate the peculiarities of mechanochemical synthesis, the changes in shape and size of the titanium particles occurring during their mechanical treatment up to the moment of synthesis have been examined. Titanium and zirconium powders with particles differing drastically in shape and size have been used for the synthesis of TiB₂ and ZrB₂ by SHS. It has been shown that irrespective of the difference in properties of the reagents, the products obtained have some common properties characteristic of the synthesis method and important with respect to the practical applications of the borides of titanium and zirconium.     

Mechanical alloying and milling

Mechanical alloying (MA) is a solid-state powder processng technique involving repeated welding, fracturing, and rewelding of powder particles in a high-energy ball mill. Originally developed to produce oxide-dispersion strengthened (ODS) nickel- and iron-base superalloys for applications in the aerospace industry, MA has now been shown to be capable of synthesizing a variety of equilibrium and non-equilibrium alloy phases starting from blended elemental or prealloyed powders. The non-equilibrium phases synthesized include supersaturated solid solutions, metastable crystalline and quasicrystalline phases, nanostructures, and amorphous alloys. Recent advances in these areas and also on disordering of ordered intermetallics and mechanochemical synthesis of materials have been critically reviewed after discussing the process and process variables involved in MA. The often vexing problem of powder contamination has been analyzed and methods have been suggested to avoid/minimize it. The present understanding of the modeling of the MA process has also been discussed. The present and potential applications of MA are described. Wherever possible, comparisons have been made on the product phases obtained by MA with those of rapid solidification processing, another non-equilibrium processing technique.