crystallization

摘要： Erythromycin thiocyanate is widely used for the production of other macrolide antibiotics. In this work, a novel heterosolvate of this pharmaceutical compound has been obtained and characterized for the first time, which was transformed from the dihydrate form in the acetone solvent through evaporation crystallization. Thermal behavior together with compositional analysis revealed that both water and acetone molecules participated in the formation of the crystal lattice which is rarely reported before. The general chemical name of the heterosolvate may be defined as erythromycin thiocyanate sesquihydrate hemiacetonate. Furthermore, studies on solid-state spectral analysis provided strong evidence of intermolecular hydrogen bonds in heterosolvate crystals. According to the crystal structure determined by single crystal X-ray diffraction, the formation mechanism of the heterosolvate is proposed in which strong multihydrogen bondings between water and solute molecules form the layer structure. While acetone molecules form single-hydrogen bonds with solutes and reside in channels between layers. This well explains why acetone solvent is easy to escape from the crystal structure during desolvation.

摘要： With the development of digital products,electric vehicles and energy storage technology,electronic chemicals play an increasingly prominent role in the field of new energy such as lithium-ion batteries.Electronic chemicals have attracted extensive attention in various fields.Characteristics of high-end electronic chemicals are high purity and low impurity content,which requires a very strict separation and purification process.At present,crystallization is a key technology for their separation and purification of electronic chemicals.In this work,the representative fluorine-containing compounds in cathode and anode materials,separator and electrolyte of lithium-ion batteries are introduced.The latest technologies for the preparation and purification of four kinds of fluorine-containing battery chemicals by crystallization technology are reviewed.In addition,the research prospects and suggestions are put forward for the separation of fluorine-containing battery chemicals.

摘要： In order to extend the usage of PLA-based nanocomposites, the modification of multi-walled carbon nanotubes (MWCNT) and preparation of surfactant modified carbon nanotubes (SMCNT) involved PLA nanocomposites (PLA/SMCNT) were investigated. The morphologies, electrical properties and crystallization behavior of PLA/SMCNT composites were investigated. The TEM images indicated that SMCNTs were dispersed homogenously in the PLA matrix without forming aggregates. The electrical conductivity of PLA/SMCNT was greatly improved and the percolation threshold of PLA/SMCNT was calculated to be 0.61% which is much lower than 1.45% of PLA/MWCNT composite. The crystallization behavior suggested that SDBS together with MWCNT acted as heterogeneous nucleating agent and accelerated the nucleation. Meanwhile, the SMCNT also devoted further restrained effect to spherulites growth due to its well dispersion and improved compatibility with matrix.

摘要： The crystallization behavior,crystal morphology and form,and viscoelastic behavior of poly(butylene succinate)(PBS)and coir fiber/PBS composites(CPB)were investigated by differential scanning calorimetry(DSC),polarized optical microscopy(POM),X-ray diffraction(XRD)and dynamic mechanical analysis(DMA).The results of DSC measurement show that the crystallization temperature increases with the filling of coir fibers.POM images reveal that the spherulitic size and crystallization behavior of PBS are influenced by the coir fibers in the composites.XRD curves show that the crystal form of pure PBS and CPB are remaining almost identical.In addition,the storage modulus of CPB significantly increases comparing with the pure PBS.This predicted the dimensional stability and improved load-deformation temperature.In conclusion,the addition of coir fibers has a significant effect on the thermal properties of the matrix.

摘要： The fundamental science behind glass and glass-ceramics in relation to research including syntheses, processing, characterization and applications are critically reviewed in this paper. The crystalline structure of the crystalline phases/s investigated in the literature is also discussed. Throughout this paper, the scene is set toward the overall picture of the rationale behind the choice of a glass system. Additionally, earlier reviews do not include the most recent literature in this fast-moving field. The main methods of synthesizing glasses and glass-ceramics are explained and described in relation to their applications. The paper concludes with recommendations for future research.

摘要： Polymer solar cells(PSCs)featuring nonfullerene acceptors have attracted a great deal of attention in the research community.Exposure of these active layers to sunlight during operation demands excellent thermal stability.Optimizing PSCs often requires a step of thermal annealing,while long-term annealing often places a constraint on their stable operation at elevated temperature and results in a progressive loss of photovoltaic performance.Hence,it is crucial to understand and control the fundamental affecting factors on the thermal stability of nonfullerene PSCs.This review highlights the relationships between microstructure and thermal stability of PSCs and summarizes promising strategies to push this technology toward the level of practical application.Finally,we present the current challenges and prospective of this research area,intending to advance the practical applications of stable PSCs based on nonfullerene acceptors.

摘要： Characterization of special morphology of periclase,corundum,spinel and mulllte/Gao Zhenxin,Zhang Wei,Huang Zhenwu,Wei Xiaohui〃Naihuo Cailiao.-2021,55(2):93 The crystal growth theory of periclase,corundum,spinel and mullite in different conditions was studied by means of high-resolution instruments,and the special-morphology crystals were characterized.Periclase of cubic system and euhedral spinel are typical cube and octahedron,and can also form any other shapes,such as joined crystallization and step growth,which are limited by the crystallization environment.Mullite belongs to orthorhombic system and has the long columnar crystallization habit.However,the euhedral development is often restricted by the environment.Mullite crystallizes(or peritectic reaction happens between corundum and liquid phase)into columnar shapes when there is a certain amount of liquid phase.The combination of mullite and corundum can exist in the form of simple symbiosis or peritectic reaction.periclase;corundum;spinel;mullite;microstructure.

摘要： Dear editor,Three-dimensional monolithic integration(3D-MI)has recently emerged for both"more Moore"and"more than Moore"applications,because of its high integration density,high bandwidth and multi-functions[1].With 3D-MI,different types of devices can be stacked on the same platform and in a single process flow.

摘要： A series of materials of composition Fe87Zr7B6,Fe87Zr7B5Ag1,Fe87Zr7B5Cu1 have been prepared by the melt spinning method for different cooling speed to get completely or partly amorphous ribbons.It is proved that the crystallization process is composed of 2 steps.The first step is the precipitation of&-Fe only and the second step is the phase separation of&-Fe,Fe2Zr and Fe2B.All our own made materials have been used in the library monitoring system.Most of them showed a capability of triggling the alarm of the system.The triggling sensitivity at different positions and different sample geometry were investigated and the physical mechanisms were analyzed.

摘要： Background:poly(vinylidene fluoride)PVDF and PVDF/PMMA blends have been investigated with a focus on the crystal structure,immiscibility and mechanical properties.However,few reports were found on the crystallization behaviors of PVDF and PVDF/PMMA blends,especially on crystallization kinetics.The article is to report the research on isothermal and nonisothermal crystallization kinetics for PVDF and PVDF/PMMA blends using differential scanning calorimetry(DSC).Results:Besides crystallization temperature and isothermal crystallization activation energy,the Avrami equation exponent of PVDF in blends decreased compared with pure PVDF.The nonisothermal crystallization kinetics of PVDF and PVDF/PMMA(70:30)blends were investigated by Ozawa equation,Jeziorny method and crystallization rate constant(CRC)in detail.The nonisothermal crystallization energy of pure PVDF and its blends were determined by the Kissinger and Vyazovkin’s method.Conclusion:The nucleation and growth mechanism of PVDF in blends changed compared with pure PVDF.The Ozawa equation is not applicable in nonisothermal crystallization kinetics of PVDF and PVDF/PMMA blends.The decreasing of crystallization ability of PVDF in blends were found and confirmed by CRC and the decline of crystallization rate constant in Jeziorny method.Such is opposite to the results of Kissinger’s and Vyazovkin’s method,chances are that these two methods were not used to calculate the nonisothermal crystallization activation energy where the nucleation process was influenced.