先进陶瓷快速无模成型方法研究的进展

介绍了快速无模成型的发展历史和特点,重点介绍了激光选区烧结成型（Selective Laser Sintering,SLS)、三维打印成型（3Dimensional Printing,3DP)、熔融沉积成型（Fused Deposition of Ceramics,FDC)、分层制造成型（Laminated Object Manufacturing,LOM)、立体光刻成型9Stereilithography,SL)、喷墨打印成型（Ink-jet Printing,I-JP）、选区凝胶成型（Selective Gelation,SG)和激光选区气相沉积成型（Selective Area Laser Deposition,SALD)等8种先进陶瓷的成型方法,并分析了目前该技术产业化所面临的一些问题。     

Indirect solid freeform fabrication by binder assisted slip casting

A method has been developed for the consolidation of ceramic bodies in molds prepared by solid freeform fabrication. The method is based on slip casting with an added latex binder. The latex binder makes it possible to create internal structures, such as pore channels, without the cracking that usually takes place when shrinkage is obstructed by internal mold structures. The latex binder adds plasticity to the consolidating body in the wet state. This was observed by rheological measurements during slip casting. Measurements of mechanical properties showed that the latex binder also adds plasticity and strength in the dry state.     

Development of soybean oil‐based composites by solid freeform fabrication method: Epoxidized soybean oil with bis or polyalkyleneamine curing agents system

Soybean oil‐based composites are prepared by the solid freeforming fabrication (SFF) method. Epoxidized soybean oil is solidified with a gelling agent, and composites are formed by fiber reinforcement. Glass, carbon, and mineral fibers are used in the formulations. The type of fiber and degree of fiber alignments affect the properties of the composites. In addition, the effects of curing agents, curing temperature, fiber combination, and fiber loading on mechanical properties of composites and dynamic analysis are studied and reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2100–2107, 2002     

Development of multiple-droplet drop-casting method for the fabrication of coatings and thin solid films

Spray coating is a commercial and low-cost technique for the fabrication of large-area coatings and thin films, but it is a stochastic process that is hard to control, as far as the fabrication of thin coatings and solid films is concerned. On the other hand, drop-casting is a facile and more controllable coating technique than spray coating, but its application is limited to small-area thin solid films and coatings. The objective of this work is, therefore, to study the feasibility of impinging an array of droplets, rather than just one droplet, to fabricate polymeric and other solution-processed thin films with larger surface areas than those produced by conventional drop-casting. To this end, in this study, four droplets of poly(3,4-ethylenedioxythiophene)–polystyrene sulfonate (PEDOT:PSS) solution are released simultaneously and impinged on the four vertices of a square on a wettable solid surface to make a thin film. The effect of the substrate texture on the spreading and the film formation process is studied. As a novel idea, the substrate is excited by ultrasonic vibration to improve the droplet spreading and coalescence. It is shown that as time elapses, the impinged droplets successfully coalesce and make a thin film. Surface morphology and roughness of the resulting PEDOT:PSS thin solid films show that, except on the edges, the resulting thin solid films are uniform. This leads us to conclude that the application of equal-sized and equally-spaced multiple droplets released simultaneously and impinged on vibrating substrates could be considered as a new coating technique, which has some of the benefits of the spray coating, but it is much more controllable than spray coating.     

Solid freeform fabrication of soybean oil-based composites reinforced with clay and fibers

Soybean oil/epoxy-based composites were prepared by an extrusion freeform fabrication method. These composites were reinforced with a combination of organically modified clay and fibers. The intercalated behavior of the epoxy resin in the presence of organo-modified clay was investigated by X-ray diffraction and transmission electron microscopy. The mixture of epoxidized soybean oil and EPON^® 828 resin was modified with a gelling agent to solidify the materials until curing occurred. The flexural modulus reached 4.86 GPa with glass fiber reinforcement at 50.6 wt% loading. It was shown that the fiber orientation followed the direction of motion of the writing head that deposited the resins and had an influence on the properties of the composite. The composites cured by curing agent jeffamine EDR-148 were found to have lower mechanical properties than those cured with triethylenetetramine, diethylenetriamine, and polyethylenimine. In addition, the effects of clay loading and fiber loading on mechanical properties of the composites were studied and reported.     

复印墨粉用四氧化三铁的制备

主要研究了在碱性条件下，由经过处理的工业级硫酸亚铁和氢氧化钠通过氧化沉淀的方法，制备适合复印墨粉用高档四氧化三铁磁粉。介绍了硫酸亚铁和氢氧化钠的反应原理、工艺流程以及不同的m（Fe）／m（NaOH）、加料方式、反应体系的pH、鼓气量、鼓气时间、以及分散剂对产品性能的影响。制备的四氧化三铁磁粉纯度高，颗粒大小均匀，磁性能好，价格低廉，能够满足国内复印机市场需求。     

彩色墨粉聚合生产工艺研究进展

彩色墨粉是激光彩色打印、复印的主要耗材之一。本文对彩色墨粉的主要生产工艺——聚合工艺进行了介绍，并概述了彩色墨粉的研究生产现状，指出了随着办公自动化、数字化、多彩化的发展，彩色墨粉具有非常重大的现实意义和广阔的市场前景。     

Controlled aggregation of colloidal particles for toner applications

Micrometer‐sized particles were formed by controlled aggregation of carboxylated polystyrene colloidal spheres having a mean diameter of about 200 nm with a commercial cationic coagulant. To identify the parameters governing the size and structure of the aggregates, the aggregate size distribution was studied over a period of time with dynamic light scattering. The effect of the particle concentration, pH, and ionic strength on the aggregation behavior was investigated. The coagulant concentration used for present studies was 5 parts per hundred on the basis of the polystyrene particles and the particle concentrations used were 10–15%. The particle size distribution for the latex suspensions was also investigated with a 10% aluminum sulfate [Al₂(SO4)₃·14H₂O] solution as a model coagulant. With the commercial coagulant, aggregation was found to be slower at lower pH than at neutral pH. At pH 6, the particles started to aggregate within minutes and form aggregates of about 1000 nm. We expected that lowering the pH would reduce interparticle repulsive forces and enhance the collision efficiency. However, at a lower pH of 2, the aggregation process slowed down. Increasing the ionic strength at neutral pH led to a broader aggregate size distribution, and the population of larger aggregates increased. The suspensions with the model coagulant showed similar behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

环己酮自缩合固体催化剂的研究

研制了一种应用于环己酮自缩合反应的新型固体催化剂CC-1。与传统的浓硫酸催化剂相比，CC-1催化剂具有更优异的选择性，操作更简便。通过对不同用量的带水剂包括环己烷、正庚烷以及甲苯的使用效果进行考察，发现以用量为50 mL的正庚烷作带水剂的效果最理想，环己酮的转化率和二聚物的选择性分别达到87.5%和97.9%。对CC-1催化环己酮缩合反应的进程研究表明，该反应具有典型的连串反应特点。对CC-1催化剂的再生性能考察表明,该催化剂具有优良的再生性能，至少可以再生8次，维持催化剂活性在转化率85%和选择性96%左右。     

A dynamic liquid support system for continuous electrospun yarn fabrication

Electrospinning is known to be a highly versatile process which is able to produce fibers made out of different compositions with diameter of a few microns down to several nanometers. Current electrospinning technology generally involves the deposition of fibers onto a solid substrate although in some cases, a liquid coagulation bath is used to collect the fibers. However, a liquid collector may offer several advantages over a solid substrate. A novel electrospun fiber manipulation process through the use of a water vortex is described in this communication where continuous yarn was made from electrospun fibers. Preliminary studies on some parameters such as solution feed rate and solution concentration and their impact on fabrication of the yarn and the fiber morphology were carried out.     

Ionic liquid assisted fabrication of cellulose-based conductive films for Li-ion battery

An imidazolium-based ionic liquid, 1-ethyl-3-methylimidazolium diethyl phosphate ([Emim]DEP) was used to dispense graphene nanoplates (GN) and multiwalled carbon nanotubes (MWCNTs) as well as dissolve cellulose for fabricating composite conductive films. The effects of GN, MWCNTs, and cellulose mass ratios on the electrical conductivity and morphology of the films were investigated. The interaction between GN, MWCNTs, and cellulose was analyzed by SEM, X-ray diffraction (XRD), TGA, and Raman spectroscopy. The results indicate that [Emim]DEP plays a vital and irreplaceable role in GN and MWCNTs dispersion, cellulose dissolution, and porous formation during the regeneration and drying processes. MWCNTs linked flaky GN and a hybrid structure was constructed elaborately to form a better conductive path and improve the conductivity as well as increase the film stability. For the XRD result, the carbonized GN-MWCNTs-cellulose films exhibited the graphitic peaks, showing that the films still retained the structure of carbon atoms or molecules. Besides, the maximum conductivity of carbonized GN-MWCNTs-cellulose (7:3:2) composite film was up to 9,009 S m⁻¹, due to the small carbon clusters formation and the high degree of graphitization. Further, the carbonized films were applied as anodes in Li-ion battery and showed good electrochemical performance. The best cyclic stability (i.e., discharge/charge capacity) of 438/429 mA h g⁻¹ and coulomb efficiency of 50.2% were obtained. This novel and sustainable design is a promising approach to obtain cellulose-based conductive films and anodes for Li-ion battery applications.     

静电色调剂材料的设计

本文从静电显影原理对静电色调剂在显影密度、电阻率、机械强度、定影温度、吸湿率等方面的要求入手分析并设计静电色调剂材料,以求使色调剂的质量得到较大的提高.     

Motion of a solid sphere in a horizontally oscillating liquid

The behaviour of a single dense sphere in a horizontal tube containing an oscillating liquid has been studied experimentally and theoretically. The experiments were carried out using steel, glass and nylon spheres in water or dilute glucose solutions in a 5·08 cm diameter horizontal tube, at oscillation frequencies of 0·4 to 1·3 Hz. The measured amplitude of oscillation of the spheres agreed fairly well with predictions from the equation of motion of the spheres. It was necessary to allow for the rotational inertia of the rolling spheres and quasi-steady drag behaviour was assumed. Solid—solid friction and boundary layer effects were not included in the analysis and were responsible for some deviations between observation and prediction.     

Development of an easily deinkable copy toner using soy‐based copolyamides

To develop an easily deinkable toner for office copiers and laser printers, a series of homo‐ and copolyamide toner resins were synthesized via condensation polymerization of a soy‐based dimer acid, 1,4‐phenylenediamine, and L ‐tyrosine (an α‐amino acid). The thermal properties of the resins were examined using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). It was found that the glass transition temperature (T_g), melting point (T_m), decomposition temperature (T_d), and crystallinity of the copolyamides were remarkably decreased as the content of L ‐tyrosine was increased. By using both homo‐ and copolyamides as binders, respectively, two dual‐component toners were developed. The triboelectrical charge, particle size, and particle‐size distribution of these toners were examined. The printing trials demonstrated that the images of the soy‐based toners are similar to those of commercially available toners. However, because of the low crystallinity and high water‐uptake ability of the amino acid‐containing polyamide, the copolymer is swellable in an alkaline solution. Initial results from flotation deinking suggest that the amino acid‐containing toners are more easily deinked, likely due to their high swellability. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1563–1570, 1999     

The coupled relaxation model for toner melt rheology

Process changes aimed at improving printer engine performance must take into consideration not only the process variables (such as nip temperature and pressure and process time t_o), but also the melt rheological variables (such as the characteristic time scale of the toner T_c). The melt rheology relevant to the electrophotographic toner fusing process is discussed. One criterion for toner quality can be conveniently measured through the Deborah number De, which is the ratio of T_c to t_o. Modification of the melt rheology by matrix polymer composition and carbon black size and concentration has previously been explored. Here, the melt rheology of toners with a range of gel content was studied using a step shear test. The coupled relaxation model was employed to fit the stress relaxation data. The viscoelastic properties were calculated from the melt data with this model. These properties were then used to estimate the strain deformation of the toner as it passes through the nip with arbitrary residence time and nip pressure as a function of gel content. This method can be used to match the toner melt properties with the processing conditions.     

结晶聚酯型墨粉主体树脂的合成与性能研究

合成了一种软化点范围适合作墨粉的结晶聚酯,该聚酯以反丁烯二酸和羟乙基双酚A为原料采用熔融缩聚的方法制备而成;探讨了单体羟乙基双酚A的合成方法并研究了反应物物质的量比和催化剂对合成羟乙基双酚A的影响;考查了反应物物质的量比以及反应温度对结晶聚酯合成的影响,对其流变性和软化点作了测试并与商用墨粉用树脂进行比较。     

Optimization of a ScCeSZ/GDC bi-layer electrolyte fabrication process for intermediate temperature solid oxide fuel cells

Cost-effective wet ceramic coating techniques for fabricating ScCeSZ/GDC bi-layer electrolyte anode-supported button cells were investigated in this study. Aqueous ceramic slurries were prepared by ball milling and then used for Ni/ScCeSZ half cell fabrication by tape casting and spin coating. Prepared cells were tested at operating temperature between 700 and 800°C with a fuel composition of hydrogen:nitrogen 3:1 and air at the cathode. The cell with a spin coated GDC film showed the maximum power density of 1.142, 1.012, 0.813 W?cm^?2 at 800, 750, and 700°C, respectively. It was also able to produce power output around 0.7 W?cm^?2 for 500 h at 750°C, which confirms the cell operational stability. More importantly, the GDC film prepared by spin coating effectively avoided the formation of the (Zr,Ce)O₂^?based solid solution at the ceria/zirconia interface compared with the other cells with the co-casted and sintered GDC film.     

Laminar flow of a liquid rivulet down a vertical solid surface

Conditions for an energy minimum of a liquid rivulet flowing down a vertical solid surface have been considered. The solution of the equation may yield a constant value equal to the maximum rivulet thickness and the curve z(x) representing the shape of the rivulet cross section (profile). The profile describes the smallest rivulet which may be formed for a given system. “Composed” solutions correspond to wider rivulets, e.g. finite films. Numerical integration has been performed over a wide range of the parameter characterizing the liquid, at contact angles ranging from 5° to 90°. The minimum rivulet concept, which makes it possible to describe a finite-width laminar film of minimum thickness, extends the Nusselt theory.     

Phase equilibrium of a liquid droplet formed on a solid particle

An equation of state of a two-phase system, deduced from the principles of classical thermodynamics, is used to illustrate the effects of interface curvature, electric charge, a soluble substance, and of disjoining film pressure on the equilibrium of a liquid droplet formed on a solid particle. The former three effects have been widely discussed in the past, whereas the effect of the disjoining film pressure has not been explored. The focus of the paper is, therefore, placed on the effect of the disjoining film pressure on the droplet equilibrium. Opposing the action of surface tension, the disjoining pressure is shown to lower the equilibrium vapour pressure at constant temperature and to increase the equilibrium temperature at constant pressure in comparison to the equilibrium in the reference state. This interplay provides a way bringing experimental findings in a better agreement with theoretical models.