以活性氧化镁和氯化镁为原料合成氧化镁晶须

探讨了一种合成氧化镁晶须的新的工艺方法。首先以活性氧化镁和氯化镁为原料合成了前驱体碱式氯化镁晶须，接着将碱式氯化镁焙烧成氧化镁晶须。分别用X射线衍射仪（XRD）、扫描电镜（SEM）、热重分析仪（TGA）和化学分析，分析了中间体碱式氯化镁和产品氧化镁晶须的成分、形貌和热化学行为。探讨了各个工艺条件对产物的影响，探索出最佳的工艺条件：活性氧化镁与氯化镁的物质的量比在0．08左右，氯化镁溶液的浓度为3mol／L，反应温度40～50℃，陈化时间在48-72h，陈化温度50℃。在此条件下制得了形貌良好的前驱物碱式氯化镁晶须。将碱式氯化镁晶须焙烧，控制升温速率在2—5℃／min，采取分段升温方式升温至600℃，即可制得氧化镁晶须。制得的晶须长度在100μm左右，直径约0．5μm。     

碱式硫酸镁烧结法制备氧化镁晶须

以价格低廉的硫酸镁和氢氧化钠为原料,通过前驱体烧结法制备氧化镁晶须。首先以硫酸镁和氢氧化钠为原料,通过常温反应—水热晶化,制得了结晶良好、具有纤维状外形的前驱体碱式硫酸镁[MgSO4.5 Mg(OH)2.2 H2O]的单一物相。通过控制前驱体的分解速度使其在低温下缓慢分解以保持晶须状外形,然后在高温下烧结,得到烧结良好、分散均匀、长径比大的氧化镁晶须。利用SEM和XRD对产物进行表征,氧化镁晶须是由纳米氧化镁颗粒烧结而成的“假象”体,直径在0.2~1.5μm,长径比≥50。实验证明该工艺简捷、易行、条件温和,为氧化镁晶须的工业化生产提供了有效可行的新途径。     

A new sol-gel route to prepare dense Al2O3 thin films

Anew sol-gel route has been applied to synthetize dense Al₂O₃thin films from aluminum isopropoxide (Al(OPri)₃)as raw precursor material. The results show that, in the solution, acetylacetone (AcAc) and aluminum form a complex compound which effectively suppresses the growth of colloidal particles and makes the sol very stable. Al₂O₃thin films fabricated by spin-coating method and calcined at 500 °C for 3 h possess an amorphous structure and exhibit a highly homogeneous surface texture without evidence of holes or cracks throughout the film. Moreover, the prepared films display a low leakage current and a high transmittance. This new sol-gel route appears to be a highly promising method to synthetize dense Al₂O₃ thin films from Al(OPrⁱ)₃, and could provide a wide range of optical and electric applications.     

合成精胺盐酸盐的新方法

以糖精为原料合成精胺。用1,4-二氯丁烷将糖精烃基化,然后将所碍烃基化产物1,6-二(邻酰基苯磺酰基)-1,6-二氮杂已烷(Ⅰ)在碱性条件下水解得到1,6-二(邻-羟基甲酰基苯磺酰基)-1,6-二氮杂己烷(Ⅱ),(Ⅱ)再与丙烯腈进行Michael加成反应,生成4,9-二(邻-羟基甲酰基苯磺酰基)-4,9-二氮杂十二二腈(Ⅲ),在双催化剂(Raney Ni-Pd／C)存在下使用催化加氢生成5,10-二(邻-羟基甲酰基苯磺酰基)-1,5,10,14-四氮杂十四烷(Ⅳ),后者在盐酸中水解生成精胺盐酸盐(Ⅴ),总收率达到26％。     

A modified two-Stage mixed oxide synthetic route to lead magnesium niobate and lead iron niobate

A modified mixed oxide synthetic route has been developed for the synthesis of lead magnesium niobate [Pb(Mg_1/3Nb_2/3)O₃; PMN] and lead iron niobate [Pb(Fe_1/2Nb_1/2)O₃; PFN] powders. The formation of perovskite and pyrochlore phases in the calcined PMN and PFN powders has been investigated as a function of calcination temperature and time by XRD and DTA techniques. The particle size distribution of calcined powders was determined by laser diffraction, with the morphology, phase composition and crystal structure determined via SEM, TEM and EDX techniques. In both cases it has been found that cubic pyrochlore phases in the PbO–Nb₂O₅ system tend to form, as well as the perovskite phase. However, pyrochlore-free PMN and PFN powders were successfully obtained for a calcination temperature of 800°C for 4 and 3 h, respectively, without the introduction of excess PbO and/or MgO.     

A facile route to prepare homogeneous silicone resin doped with titanium

A facile route was introduced to prepare homogeneous silicone resin doped with titanium hybrid with high refractive index (RI). Specifically, the hybrids were obtained from the transesterification of hydroxyl-phenyl-vinyl silicone resin and titanium isopropoxide under anhydrous conditions. The structures of hybrid silicone and their corresponding intermediates (hydroxyl-phenyl-vinyl silicone) were characterized by nuclear magnetic resonance spectroscopy (¹H NMR, ²⁹Si NMR) as well as Fourier transform infrared spectroscopy (FTIR). The hybrids had a transmittance of more than 88% ranging from 450 nm to 800 nm, a high RI of 1.585, and a lower water vapor permeability of 3.58 g /m².24h. Results from FTIR showed intensity of Ti-O-Si bond in hybrid decrease with extended the storage time, but the properties of cured hybrids including optical, mechanical, and gas permeability were not influenced. Compared to chips encapsulated with pure silicone, the luminous efficiency of the chips encapsulated with hybrids was improved from 138.6 lm/W to 156.4 lm/W. The thermal shock and hygrothermal aging test also demonstrated the hybrids had a wide range application in light-emitting diode (LED) packaging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47834.     

硼酸镁晶须研究进展

硼酸镁晶须作为一种新型的功能材料正在金属、塑料、陶瓷、高分子等复合材料中获得应用。随着科技、经济的发展,其使用领域在不断扩展。本文主要介绍了硼酸镁晶须的制备方法及其特性,并对硼酸镁晶须发展方向进行了展望,这对于硼酸镁晶须的应用和工艺改进有重要的参考价值。     

A green route to prepare cellulose acetate particle from ramie fiber

A novel procedure for synthesizing cellulose acetate particles from ramie fiber was developed. The optimum conditions for preparing cellulose acetate (CA) by reaction of ramie fiber with acetic anhydride under an acidic condition were determined. Reaction was carried out in a ratio of ramie fiber to acetic anhydride of 1:6 (w/w) at 80 °C for 0.5–1 h. When CA was added to a mixture of water and acetone, CA particles with a well-distributed diameter ranging from 5 to 15 μm were obtained. The difference of the CA particle surface was resulting from different washing methods of CA particles with water or aqueous sodium bicarbonate. The highest degree of substitution (DS) of 2.50 for CA by titration method was achieved. A new adsorbent was prepared from CA, which is an excellent sorption regent for organic waste in water. The scanning electron microscopy (SEM) and particle size distribution results showed that the average size of CA particles is about 5–15 μm in diameter. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to determine the stability of ramie fiber and CA particle.     

A new reducing agent to prepare single-layer, high-quality reduced graphene oxide for device applications

We report on a novel, efficient, and one-step approach to prepare single-layer reduced graphene oxide (RGO) suspensions and films using hydroxylamine hydrochloride. The effective chemical reduction of GO was evidenced by a significant increase in the C/O ratio and five orders of magnitude decrease in the GO resistance. Field-effect transistor gas sensors were fabricated using as-produced RGO sheets and the resulting sensor exhibited a fast response and a high sensitivity to low-concentration target gases at room temperature.     

A new route to prepare supported nickel phosphide/silica–alumina hydrotreating catalysts from amorphous alloys

Supported nickel phosphides were prepared by treating an amorphous Ni–B alloy on silica–alumina support with phosphine (15 vol.% PH₃/H₂) at relatively low temperature. The amorphous Ni–B/SiO₂–Al₂O₃ precursors were synthesized by silver-induced electroless plating. The amorphous precursors and catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction, BET surface area and inductively coupled plasma measurements. The transmission electron micrographs of the Ni₂P/SiO₂–Al₂O₃ particles with their size ranging from 60 to 80 nm showed that they were homogeneously dispersed over the SiO₂–Al₂O₃ support. The as-prepared catalysts exhibited an excellent catalytic activity in the hydrodesulfurization (HDS) of dibenzothiophene.     

A facile and reliable route to prepare of flower shaped lead sulfide nanostructures from a new sulfur source

Flower shaped PbS nanostructures were prepared by the solvothermal method using propylene glycol and a new sulfuring agent. Novelty of this work is application of a new thio Schiff-base as complexing and sulfuring agent for synthesizing of PbS nanostructures. SEM and TEM was used to examine the surface morphology of the grown samples; also the products were characterized by XRD, SEAD, UV–vis and FT-IR spectra. The results of this paper indicate that the shape and size of lead sulfide nanocrystals can be controlled systematically by setting certain reaction parameters.     

两段氧化法制备四氧化三锰

为了优化两段氧化法制备四氧化三锰的工艺，分别采用单因素试验和正交试验探讨反应温度、锰离子的加料速度、氨锰物质的量比、固相氧化温度、固相氧化时间对总锰质量分数的影响。试验得出制备四氧化三锰的工艺条件为：原料氨锰物质的量比2：1，锰离子的加料速度30mL／h，反应温度95℃，固相氧化温度200℃，固相氧化时间3h。在最佳条件下制备的四氧化三锰是γ-Mn3O4，总锰质量分数为71．0％，平均粒径为1．23μm。     

酸性氧化电位水制备新工艺

对EOW制备工艺中离子膜类型、电解方式和碱性水回流3个方面进行了考察,发现利用均相阴离子交换膜代替均相阳离子交换膜,可以有效地提高电解效率,原因在于阴离子膜可以有效地阻止H 的反渗透;采用阴、阳电解槽同时加入电解质溶液并采用阴离子膜的电解方式最优;当回流比在40%～60%时可以得到合格的EOW,回流比为80%时得到EOW的pH值超出范围;回流比对EOW的ORP值和ACC值影响不大.设计了EOW制备的新工艺,提高了制备效率和电极使用寿命,减少了碱性水的排放.     

Electrochemical synthesis of magnesium borate whisker

This study successfully synthesised magnesium borate (Mg₂B₂O₅) whiskers using a simpler electrochemical method and lower energy consumption compared with traditional methods. Metallic magnesium was anodised under low-voltage conditions in a borate solution containing ethanol/water mixtures and poisoning agents. The composition and morphology of the magnesium borate whiskers were determined by X-ray diffraction and scanning electron microscope measurements, respectively. The magnesium borate whiskers were 6–8 μm long, each with a diameter of 500 nm. The ratio of the length to the diameter ranges from 12:1 to 16:1. The average current efficiency was 72.6%.     

硼酸镁晶须的研究进展及其应用

总结分析了硼酸镁晶须的研究进展,并对其应用进行了综述.采用高温固相合成法、微波固相合成法及水热合成法等方法可以制备出硼酸镁晶须,并且将其应用于金属复合材料、塑料复合材料、陶瓷复合材料和高分子材料中.硼酸镁晶须与其他晶须相比,不仅生产成本低、制备条件温和.而且具有优异的力学性能、耐热性和耐腐蚀性能,是一种具有应用潜力的新型增强材料,在复合材料制造中具有非常重要的价值、广阔的市场和应用前景.     

氢氧化镁晶须的制备与应用

氢氧化镁晶须具有低的表面能、良好的机械强度、高弹性模量等特性,作为阻燃剂和增强材料有着独特的优势,具有广阔的应用前景.目前,氢氧化镁晶须多以天然镁矿石或其他镁盐为原料,通过水热/溶剂热反应制得.较为详细地介绍了氢氧化镁晶须的制备方法及其应用,对氢氧化镁晶须的制备机理和影响其形貌的因素也做了简要介绍.     

镁盐晶须的应用与开发

作为一种新型无机功能材料,镁盐晶须(M-HOS)凭借其独特、优异的性质,在诸多领域有着十分广阔的应用前景。介绍了镁盐晶须的制备原理和工艺路线,主要对水热法和镁盐熔融法的工艺路线、工艺条件和特点进行了阐述。并介绍了镁盐晶须在塑料、尼龙-6、造纸、涂料等领域的应用,对其在各个领域的独特性能进行简要分析,并对镁盐晶须未来的发展提出展望。     

硼酸镁晶须的制备与应用研究

系统地介绍了硼酸镁晶须在制备工艺及其应用技术领域的国内外研究现状,通过详细对比分析当前各种硼酸镁晶须的制备方法,回顾硼酸镁晶须的应用范围和增强效果,指出了硼酸镁晶须在制备、应用中存在的问题,以期对中国硼酸镁晶须的开发和综合利用起到促进作用。最后就硼酸镁晶须今后的发展趋势作了展望。     

硼酸镁晶须的合成研究

报道了硼酸镁晶须的合成研究结果。硼酸镁晶须是一种性能价格比高的晶须产品，利用熔盐法合成出长10—50μm、直径0．5—2μm的硼酸镁晶须。还就硼酸镁晶须增强复合材料的研究和硼酸镁晶须工业化的前景作了展望。