溶胶–凝胶法制备氧化铝–氧化锆复合粉体

以AlCl3.6H2O和ZrOCl2.8H2O为起始原料、NH3.H2O为沉淀剂,采用溶胶–凝胶法制备Al2O3含量为51.74%(质量分数,下同)、ZrO2含量为44.95%的Al2O3–ZrO2复合粉体。借助X射线荧光分析仪、X射线衍射仪、高温热重仪、激光粒度分析仪和扫描电子显微镜对复合粉体的化学成分、物相组成和粒径分布等进行了表征。结果表明:Al2O3–ZrO2复合粉体化学成分均匀性好,粒径较细,粒径小于0.5μm的约为5%,在0.5～5.0μm的约为55%,大于5.0μm的约为40%;随热处理温度升高,复合粉体析晶程度逐渐提高,800℃热处理时t-ZrO2相析出量较少;1200℃热处理时则析出大量的t-ZrO2相、少量刚玉相和微量c-ZrO2相;1350℃后,刚玉相和c-ZrO2相数量明显增多。

木材表面涂玻璃层方法

为了改善木材的装饰性能及提高木材硬度和强度,美国华盛顿大学研制成了用溶胶—凝胶法新工艺对木材表面进行玻璃化处理的方法。溶胶—凝胶工艺是现代材料科技领域一项新成就,用它代替传统烧成和熔融工艺可以制备各种新型的材料,用溶胶—凝胶工艺还可以在各种材料(例如金属、陶瓷、玻璃、木材等)上涂膜和涂层。本文介绍是如何在木材表面进行涂玻璃层。 众所周知,普通硅酸盐玻璃主要成份是二氧化硅,尤其是石英玻璃,二氧化硅含量占98％—99％,木材表面涂玻璃层主要是涂石英玻璃。石英玻璃具有一系列的优良性质:高的热稳定性、高的强度、高的熔化温度和软化温度,以及高的耐腐蚀性和耐磨性等。

Effects of Na content on structure and electrochemical performances of Na_xMnO_(2+δ) cathode material

Sodium manganese oxides,NaxMnO2+δ(x = 0.4,0.5,0.6,0.7,1.0;δ = 0-0.3),were synthesized by solid-state reaction routine combined with sol-gel process.The structure,morphology and electrochemical performances of as-prepared samples were characterized by XRD,SEM,CV,EIS and galvanostatic charge/discharge experiments.It is found that Na0.6MnO2+δ and Na0.7MnO2+δ have high discharge capacity and good cycle performance.At a current density of 25 mA/g at the cutoff voltage of 2.0-4.3 V,Na0.6MnO2+δ gives the second discharge capacity of 188 mA·h/g and remains 77.9% of second discharge capacity after 40 cycles.Na0.7MnO2+δ exhibits the second discharge capacity of 176 mA·h/g and shows better cyclic stability;the capacity retention after 40 cycles is close to 85.5%.Even when the current density increases to 250 mA/g,the discharge capacity of Na0.7MnO2+δ still approaches to 107 mA·h/g after 40 cycles.

Excellent Cracking Performance of Macroporous Amorphous Aluminosilicate Catalyst

Micrometer-scale macroporous aluminosilicate catalyst was prepared via the sol-gel process. Results of catalytic cracking of 1, 3, 5-triisopropylbenzene showed that the synthesized aluminosilicate catalyst exhibited much higher activity than traditional ZSM-5 zeolite under the same condition. It is worth mentioning that the polymer product selectivity of aluminosilicate was much lower than that of ZSM-5, which might be useful for implementing the catalytic cracking process. The unique structure of macroporous aluminosilicate with interconnected-macropores and continuous skeletons was believed to be responsible for its excellent catalytic activity and low polymer product selectivity. Detailed discussion on the reaction pathway was also conducted.

Preparation of Composite Phase Change Material Based on Sol-Gel Method and Its Temperature-Adjustable Textile

In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition,the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter,respectively. According to the analysis of main influencial factors of the property of CPCM,the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place,and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance,the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides,the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result,a desirable temperature-adjustable function appeared.

PREPARATION OF POLYSULFONAMIDE/TiO_2 NANOCOMPOSITES BY SOL-GEL

Polysulfonamide(PSA)was synthesized at room temperature,the polymerization based on terephthaloyl chloride and 3,3’-diaminodiphenylsulfone in the common solvent N,N-Dimethyl-acetamide(DMAc).Polysulfonamide/titanium oxide nanocomposites were prepared by sol-gel method.Tetrabutyl titanate(TBT)was added into the polysulfonamide solution,at the same time,some water was mixed to make the TBT hydrolyze.In the process,hydrochloric acid was used to catalyze the reaction.The polysulfonamide chemistry structure was characterized by FT-IR spectrum.Atomic force microscopy(AFM)was employed to observe the microstructure of the composite film.The thermal property was investigated by TGA.The results show that we have succeeded to synthesize the polysulfonamide,TiO2 particles were well distributed in the composite film and average size was about 20 nm on average,the heat-resistance of nanocomposite was batter than the pure polysulfonamide.

Optimization of the preparation process of nano TiO2 with sol-gel method at low temperature

In this paper, preparation process of nano TiO2 with sol-gel method at low temperature was optimized by response surface method. The nano TiO2 was analysised by DRS and XRD. Result show that： 20mL tetrabutyl titanate, 10mL acetic acid, 6mL ethanol dosage, aging time was 29h, aging temperature was 36℃, Nano TiO2 was prepared under the condition. Particle size of nano particles was 37.3nm, Photodegradation rate was 90.2%. It had good photocatalytic ability.

The Physical Properties and Photocatalytic Activity of CulTEA Doped TiO2-Nanoparticles Prepared by the Sol-Gel Process

Cu/TEA-doped TiO2 nanoparticles were prepared by the sol-gel process. Titanium （IV） isoproxide, copper （II） nitrate trihydrate and triethanolamine were used as precursors and calcined at a temperature of 400℃ for 2 h with a heating rate of 10℃/min to produce powders. Different interstitial amounts of TEA were added in the range of 0 mol% to 15 mol% of TiO2. The X-ray diffractrometer patterns show the TiO2 nanocomposites have a high anatase phase. It was also apparent that doped TEA has an effect on the crystallite size of TiO2 composite nanoparticles. The morphology of the composite powders was characterized by scanning electron microscope. The photocatalytic activity of Cu/TEA-doped TiO2 nanoparticles was evaluated through the degradation of methylene blue under UV irradiation. The results showed that 1 mol% TEA of TiO2 nanocomposites exhibited high photocatalytic activity and a small crystallite size.

Study on Drying Process of 3Al_2O_3·2SiO_2 Mullite Gel

Monophasic mullite gel with composition 3Al2O3·2SiO2 was prepared by the sol-gel method using aluminium nitrate nonahydrate, aluminium-tri-isopropoxide, and tetraethylorthosili-cate as reagents. Gels with different drying control chemical additives(DCCAs) and polyvinylpyrrolidone(PVP) as spinning assistant were dried at several temperatures. The influences of temperature, DCCAs and PVP in the drying process were investigated. N,N-dimethylformamide(DMF) was the optimum DCCA at 70℃ in the drying process. PVP decreased the solvent volatilization speed and prevented gel crack to a certain extent. FTIR results revealed that free water, ethanol, and isopropanol were completely removed by the drying procedure.