反溶剂重结晶法制备萘普生超细微粒

在溶剂(丙酮)-反溶剂(水)体系下,采用反溶剂重结晶法制备了超细萘普生微粒。研究了不同溶剂-反溶剂体积比、重结晶温度、表面活性剂用量及陈化条件对重结晶产物粒径和形貌的影响。采用扫描电子显微镜(SEM)、表面吸附(BET)、红外光谱(IR)、X射线衍射(XRD)等检测手段对原料药和重结晶产物进行了对比分析。实验结果表明,当溶剂与反溶剂体积比为1:20,重结晶温度为4～8℃,表面活性剂聚乙烯吡咯烷酮(PVP)的质量分数为0.5%～1.0%,60℃下陈化2 h时。可得到短径300～500 nm,长径1～2μm的超细萘普生粉体。重结晶所得产物的晶型和物理性质均未发生变化,但粒度显著减小,形貌趋于规整且比表面积增加至原料药的5.3倍。     

磁性坡缕石复合材料的制备及性能

以提纯和超细制备的纳米坡缕石矿浆与纳米Fe3O4磁性流体复合,经加热和活化处理后,制备了外包磁性微粒的磁性坡缕石纳米复合材料.当每100 g坡缕石中加入24 g纳米磁性微粒时,磁场对磁性坡缕石纳米复合材料的截留量为90.2%,其磁化率为4.3×10-2.利用化学分析、X射线衍射、红外光谱、透射电镜及磁性能测试等分析手段对磁性坡缕石复合材料进行了表征及磁性能测试,结果表明:所制备的坡缕石磁性复合材料具有高分子靶向药物载体材料的功能,有望成为新型靶向药物载体材料.     

A new test for cleaning efficiency assessment of cleaners for hard surfaces

A new test was developed to assess the efficiency of no-wiping hard-surface cleaning. The test allows cleaner comparisons according to their ability to remove greasy soils. The chosen approach minimizes the mechanical forces applied while cleaning so that the interactions between a detergent solution and the soil to be removed can be characterized. For this, immersion cleaning was chosen, with coated stainless steel as substrate and pigmented oils as the model soil. Several parameters were studied in defined ranges using the Experimental Design method and systematic comparisons. The test shows high reliability on degreasing assessments and is there-fore especially suited to optimization of nonionic surfactant mixes. The originality of the test lies in the possibility of keeping a visual trace of the cleaned substrate appearance by imprinting it on a piece of paper. The validation of the test leads to corroboration of several practical observations. Temperature and agitation play a major role in cleaning efficiency. Detergent solution concentration is a more relevant parameter than pH. Sodium carbonate is shown to have a higher buffering effect than pentahydrated sodium metasilicate. The test is easy to set up, highly sensitive, and can be adapted to solve the problems encountered by formulators of detergent cleaners, such as screening the best ethoxylated fatty alcohol mix for better degreasing properties.     

双颗粒提升管中细颗粒的混合行为研究(Ⅱ)──弥散颗粒的轴径向混合行为

利用磷光颗粒示踪技术，使用点源示踪的方法在不同的径向位置测得反映颗粒径向扩散行为的停留时间分布曲线，并对弥散细颗粒的径向混合行为进行了分析．提出二维扩散模型描述所测量的停留时间分布曲线特征．实验发现弥散细颗粒的径向扩散Peclet数随粗颗粒加入量的增加而增加，随细颗粒浓度的增大而增大，而几乎不随气速变化．给出了一个与实验数据吻合较好并可适用于单颗粒提升管的关联式．     

淤浆鼓泡床中固体粒子的悬浮特性

研究了三相鼓泡床中的临界固含率,以空气作气相,水、乙醇-水、丙酮-水、萜松醇-二甲苯作液相,石英砂、煤、雷奈镍作为固相。分析了鼓泡柱的高径比、气体速度、固体粒子的大小和比重、液体的粘度对临界固含率的影响,提出了含有这些参数的无因次数群的关联式,讨论了本文提出的关联式和文献报导的差别。     

Microstructure and fracture behavior of polypropylene/barium sulfate composites

The microstructure, mechanical properties, and fracture behavior of polypropylene (PP)/barium sulfate (BaSO₄) composites were studied. Four composite samples with different PP‐BaSO₄ interface were prepared by treating the filler with different modifiers. The fracture behavior of the composites under different strain rates was studied by means of Charpy impact tests and essential work of fracture (EWF) tests. It is shown that a moderate interfacial adhesion is favorable for toughening, which ensures that the particles transfer the stress and stabilizes the cracks at the primary stage of the deformation, and satisfies the stress conditions of plastic deformation for matrix ligaments subsequently via debonding. Very strong interfacial adhesion is not favorable for toughness, especially under high strain rate, because the debonding‐cavitation process may be delayed and the plastic deformation of matrix may be restrained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1207–1213, 2006     

脲醛树脂乳液干燥成粉末的试验研究

进行了用惰性粒子流化床干燥器将脲醛树脂乳液干燥成粉末的试验研究，产出了品质好的干粉，得出了在试验条件下的干燥强度和热效率，并作了经济性评价。     

冷冻凝聚工艺生产CR322的研制

对原电解质凝聚工艺生产CR322(混合调节型氯丁橡胶)进行了改进，实现了冷冻凝聚新工艺法生产切块CR322，即主乳化剂由松香皂／脂肪酸皂复合型代替了单一松香皂。新工艺解决了冷冻转鼓装置生产CR322过程中“黏杆”及干胶门尼黏度控制等问题。产品无焦烧粒子。且焦烧时间明显延长。     

Settling velocities of particles in bubbly gas-liquid mixtures

The axial dispersion-sedimentation model is commonly used to describe the axial concentrations of solids in three phase bubble columns at low liquid velocities. When the two parameters of this model, the particle settling velocity and the solids axial dispersion coefficient, are uncoupled by the use of various assumptions, physically unrealistic values of these parameters often result. Direct experimental measurements of solids settling rates in bubbly gas-liquid mixtures were carried out. The measured mean settling velocities decreased slightly with gas flow rate and were equal to or slightly less than the single particle free settling velocity in the liquid alone. Solids axial dispersion coefficients were also obtained from the solids settling rate distribution data, and gave values considerably less than the experimental liquid axial dispersion coefficient.     

The tribological behavior of micrometer and nanometer TiO2 particle‐filled poly(phthalazine ether sulfone ketone) composites

Micrometer and nanometer TiO₂ particle‐filled poly(phthalazine ether sulfone ketone) (PPESK) composites with various filler volume fractions from 0.5 to 7.5 vol % were prepared by heating compression molding. The friction and wear behaviors of the PPESK composites were evaluated using the block‐on‐ring test rig by sliding PPESK‐based composite blocks against a mild carbon steel ring under dry friction conditions. The wear debris and the worn surfaces of the PPESK composites filled with micrometer and nanometer TiO₂ particles were investigated by using a scanning electron microscope (SEM), while the structures of PPESK composites and wear debris were analyzed with IR spectra. Experimental results show that antiwear properties of the PPESK composites can be improved greatly by filling nanometer TiO₂ particles, and the friction coefficient decreases when the filler volume fraction is below 2.5%, but when the filler volume fraction is above 2.5% the friction coefficient increases gradually with increasing filler volume fraction. In the case of micrometer TiO₂ filler, wear rates increase with increasing filler volume fractions under identical test conditions, and the friction coefficients are less sensitive to the filler volume fraction. It was also found that the wear mechanism of micrometer TiO₂ particle‐filled PPESK is mainly severe adhesion and abrasive wear, while that of nanometer TiO₂ particle‐filled PPESK is mainly slight abrasive wear. In the former case, there are no transfer film formed on the surface of the counterpart steel, and wear debris are in the form of long and large ribbon. While in the latter case, the wear debris was granule and their size was about 10 μm. In case of 1 vol % nanometer TiO₂ particle‐filled PPESK composites, the transfer film was fairly thinner and smoother, and the transfer film provided better coverage on the surface of steel ring, while that of 7.5 vol % was thicker and discrete. These account for the different friction and wear behavior of micrometer and nanometer TiO₂ particle‐filled PPESK composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 906–914, 2004