纯丙乳胶防火涂料稳定性影响因素的研究

以纯丙乳液为主要成膜物质制备了防火性能优异,贮存稳定的防火涂料;探讨了分散剂、增稠剂、成膜助剂对乳胶防火涂料体系稳定性的影响。     

表面分散剂对电化学制备纳米铜粉的影响

为探讨表面分散剂对电化学制备铜粉的影响,以十二烷基硫酸钠、吐温20、吐温40和吐温80单独或复配作为表面分散剂,采用电化学法制备出不同形状、不同尺寸的纳米铜粉.利用XRD、TEM及FT-IR等手段对所制备的纳米铜粉的物相、形貌及粒径大小进行了分析.研究结果表明:不同的表面分散剂对采用电化学所制备的纳米铜粉的作用是不同的...     

Effect of medium condition change on green body density during casting and drying

The present study examined whether the optimum slurry conditions in which the green body with the highest packing fraction was fabricated were the same regardless of whether tape or slip casting methods were used. Additionally, we investigated the optimum slurry evaluation method to predict the packing fraction of each green body. Specifically, aqueous dense alumina slurries, whose particle dispersion state was changed by varying pH and the amount of dispersant additive, were prepared. After changing the pH, the optimum slurry conditions were achieved regardless of the casting method. The most suitable amount of additive dispersant differed due to the changing solution conditions during the casting and drying process; the medium of the slurry permeated into the plaster during slip casting and dried on the substrate during tape casting. Thus, in slip casting, non-adsorbed polymers could also be permeated. Hence, it is crucial for slurry evaluation to predict the packing fraction of the slip cast body. A sedimentation test, which involved particle condensation as well as casting, was valid for the green sheet. Conversely, it was experimentally shown that the constant pressure filtration test, which involved the permeation of the medium in addition to particle condensation, was suitable for slip casting.     

Dense and homogeneous MOX fuel pellets manufactured using the freeze granulation route

MOX fuels (UO₂-PuO₂) are used in light water nuclear reactors of several countries and are also potential candidates for the fast neutron reactors. Industrial MOX is currently manufactured by a dry route process, involving steps with fine powders. To reduce dusting, enhance MOX powder flow properties, and decrease manufacturing scrap rate, a new wet route process is investigated: the freeze granulation of concentrated water-based powder suspensions having optimized rheology and dispersion properties. Highly flowable, dustless, and easy-to-press MOX granules have been elaborated. Sintering green compacts made of such granules gives highly dense and defect-free pellets that have a very homogeneous U-Pu spatial distribution, thus improving the fuel characteristics. Indeed, MOX fuels devoid of large Pu-rich aggregates are thought to have a better behavior under irradiation in reactors by limiting/preventing the formation of the typical high burnup structure.     

Synthesis and characterization of N-alkyl-2-aminopyridinum oligomers as pour point depressants for crude oil

The synthesis of N-decyl- (C10P), N-dodecyl- (C12P) and N-cetyl-2-aminopyridinum (C16P) oligomers was achieved by oxidative polymerization of N-decyl- (C₁₀), N-dodecyl- (C₁₂) and N-cetyl-2-aminopyridinium bromide monomers respectively in aqueous acid medium. Density function theory (DFT) was applied to recognize the reactive center in monomers used. The result of quantum calculations indicated that the oligomerization could proceed via open ring reaction. The obtained oligomers were characterized using FTIR and ¹H NMR spectroscopy. In addition, the XRD and SEM were used to investigate the morphology of the prepared oligomers. The thermal stability of the obtained oligomers was followed by thermogravimetric analysis (TGA). The conversion of these oligomers is ranged from 61 to 68% and the weight average molecular weights are closed to 3000?g?mol^?1. The surface tension of the synthesized oligomers was measured at different concentrations and temperatures. The efficiency of the synthesized oligomers in depressing the pour point of crude oil was investigated. The synthesized oligomers showed high efficiency as pour point dispersants.     

Lubricating Oil Additives Based on Polyalkylpolyamines

This work is confined to the preparation and characterization of additives. These additives are based on the reaction of polyisobutylene with different ethanolamine and then amination with tetraethylenepentamine. The molecular weights of the prepared compounds were determined by gel permeation chromatography (GPC). The efficiency of the prepared compounds as antioxidant and detergent/dispersantadditives for lube oil was studied. It was found that the efficiency increases with increasing the molecular weight and -NH- group of the prepared compounds.     

染料用木质素分散剂的发展概况

综述了染料用木质素分散剂的发展概况。     

纳米二氧化钛在整理液中的分散稳定性研究

研究了不同分散剂在不同条件下对纳米二氧化钛粉体在整理液中分散稳定性的影响，采用分散相的沉降高度和分散体系中粒子的粒度分布进行评价，结果表明：六偏磷酸钠、硅酸钠、NK-1是纳米二氧化钛粉体较好的分散剂．通过测定分散相在分散递质中的Zeta电位，分析了分散剂的分散机理，说明六偏磷酸钠和硅酸钠可显著提高整理液中二氧化钛颗粒表面Zeta电位的绝对值，NK-1在纳米二氧化钛颗粒表面形成良好的溶剂化层，使纳米二氧化钛颗粒在水溶液中获得优良的分散稳定性．     

造纸法再造烟叶涂布液悬浮物富集机理分析及降黏研究

对造纸法再造烟叶涂布过程中涂布液进行黏度测定并分析涂布液离心固形物化学成分,研究了回流涂布液黏度升高的现象,找出悬浮物富集的原因,并提出回流涂布液的降黏方法。结果表明,回流涂布液的离心固形物含量高于新鲜涂布液,且主要成分为含碳物质,平均粒径为1～2μm,Ca元素含量达37%;造成回流涂布液黏度升高的主要原因是基片中细小组分间的结合强度弱,易脱落至回流涂布液,且回流涂布液中过高的Ca元素含量也是导致其黏度升高的主要因素;在回流涂布液中添加0.1%的聚乙二醇400,其黏度由416.4 mPa·s降至243.5 mPa·s,平均粒径由0.339μm降至0.116μm。     

Preparation and Evaluation of Some Lube Oil Additives Based on Polyethylene Glycol

Among the various additives employed in modern engine oils, one of the most important is the type that acts to prevent an accumulation of sludge in the crankcase and on the cylinder walls, thereby preventing sticking of piston rings and the formation of varnish-like coatings on the pistons and cylinder walls. Because of their general function of maintaining a clean engine, additives of this nature are termed detergents although it is now understood that they have little utility in cleaning a dirty engine, but by virtue of dispersing activity, prevent engine fouling. A main source of deposits is the oxidation of oil in high temperature, which can be reduced by using antioxidants. This work was limited to the preparation and characterization of different types of polyethylene glycol palmitate with different molecular weights and amination of the prepared esters with tetraethylenepentamine. The efficiency of the prepared compounds as detergents/dispersants and antioxidants was investigated and the effect of the prepared additives on other properties of lube oil was also studied. It was found that all the prepared compounds act as detergents/dispersants and antioxidant additives with no effect on the viscosity index and pour point of the lube oil.