立式捏合机捏合间隙影响CFD分析

本文利用计算流体力学(CFD)方法研究捏合间隙对立式捏合机混合性能的影响。首先,根据立式捏合机搅拌桨叶运动特点以及被混物料的流变特性,进行立式捏合机混合流场数值模拟。其次,确定立式捏合机混合性能宏观评价指标。最后,分析了捏合间隙的变化对混合性能评价指标的影响。分析结果表明：间隙越小,立式捏合机的混合性能越好;当空心桨叶两侧的捏合间隙大小相等时,立式捏合机的功耗最小。     

一种新型混合装置的开发与研究

混合与许多化工过程密切相关,为了克服传统的搅拌混合装置或结晶器的缺点,运用薄膜振动混合的理念,开发出一种新型的混合装置／结晶器。其具有低剪切应力无搅拌混合和达到固体颗粒的均匀悬浮。在完成新型混合装置的冷模设计加工后,测定了它的流型;并用脱色法测定了甘油与水调配出不同中高粘度的流体的混合时间;通过测定不同振动频率下的混合时间的变化,绘制出混合时间变化曲线,从而可确定最佳的操作条件;通过加入不同密度的固体颗粒,模拟结晶过程的固体相悬浮状况。这种新型混合装置具有较高的实用价值,市场前景广阔。     

普钙装置立式多桨混合机搅拌器的改进设计

分析立式多桨混合机搅拌器使用寿命短的原因,根据工程实例对搅拌器进行选材、结构改进和技术经济比较,达到搅拌器运行安全可靠、经济合理的目的。     

两类混合机对粉料分散影响研究

固态混合的形式有对流混合、扩散混合和剪切混合,本文以涂料粉料组分为研究对象,采用螺杆输送立式锥形混合机、双螺旋锥形混合机2种类型混合机进行试验,研究2种不同类型混合机对粉料分散效果影响。通过粉料样品对比、试样样板比对,结果表明:采用螺杆输送立式锥形混合机生产丙组分混合效果比双螺旋锥形混合机效果好,同样粉料因混合效果差异会导致色差。     

Design and characterization of modified urethane lacquer coating

A new series of natural lacquer/polyurethane (LPU) blended films were synthesized. The new lacquer/polyurethane films have very good visual color and detected gloss, fast drying time, strong weather resistance, especially against UV light and water, and a better pencil lead hardness (8H). The gel ratio increases with drying time and becomes stable after 6 months (more than 99%). The surface glass transition temperature (T_gs) obtained from a rigid-body pendulum physical properties testing (RPT) instrument showed that the new LPU films dried for 6 months have higher T_gs than polyurethane (PU) films in the following order: LPU 100 > LPU 90 > LPU 80 > LPU 70 > LPU 60 > LPU 50 > PU. Differential scanning calorimeter (DSC) results showed the same tendency as T_g but without a great gap in the LPU series except for polyurethane. Thermogravimetric analysis (TGA) showed that when the ratio of natural lacquer is more than 50%, the 50% weight loss temperatures increase about 100 °C. In addition, the reaction between lacquer and polyurethane is discussed based on the IR and NMR measurements.     

Development of an eco-friendly hybrid lacquer based on kurome lacquer sap

An eco-friendly hybrid lacquer that dries quickly in a low relative humidity environment was synthesized using kurome lacquer (KL) and volatile organic compound-free hydrolyzed amine-functionalized silane (HAS). The HAS structure was characterized by nuclear magnetic resonance (NMR), and the results showed that the ethoxysilyl group in N-(2-aminoethyl)-3-aminopropyltriethoxysilane was completely hydrolyzed. After hybridization with the kurome lacquer, the properties of the hybrid lacquer were measured in detail including viscosity, molecular weight, drying behaviors, and film hardness. Viscosity measurements confirmed the mechanism of hydrolysis and the condensation reaction of silane.     

建筑胶粘剂多功能分散机的研制及应用

实践证明性能优异的多功能分散机能有效地将各种极细粒径的粉状填料均匀的分散于结构胶的胶液中,使添加超细粒径填料的产品的技术性能有明显的提高,产品的质量也更加稳定,能生产出达到国家标准的结构胶产品。本文介绍了一种多功能分散机的设计思路、构造、特点、性能等。     

纳米ZrO2粉体在液相中分散的研究进展

综合近几年来纳米ZrO2粉体在液体介质中分散的研究情况,发现对纳米ZrO2粉体的分散研究主要集中在6个方面:pH值、盐离子(离子强度)、分散剂、固含量、液体介质和分散剂在ZrO2颗粒表面的吸附.通过这些方面的研究,人们能够得到颗粒分散均匀、不聚沉、流动性好、固含量高的ZrO2悬浮液,这就为采用胶态成型方法制备纳米ZrO2陶瓷及其复合材料奠定了基础.     

Dielectric characterization of relaxation and curing behavior of oriental lacquer

Dielectric analysis was used to investigate the effects of temperature and humidity on the curing behavior of oriental lacquer and to characterize the dielectric properties of the lacquer film. It was found that the oriental lacquer could not cure to its hardened state at relative humidity less than 50% in ambient temperature and that the cure time could be shortened tremendously by increasing the curing temperature. In order to study the dielectric properties of oriental lacquer film, two films were prepared at different curing temperatures. The glass transition and secondary relaxation temperatures of ordinary oriental lacquer film, room temperature cured purified lacquer, were observed at 45 and −40°C, respectively. The high temperature cured purified lacquer film showed a secondary relaxation at around −50°C. The relationship between thermodynamic properties and chemical structures was explored based on the analysis of the dielectric relaxation behavior using Cole–Cole plots and the dielectric relaxation intensity Δϵ. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1804–1810, 2000     

自浮颗粒的搅拌混合

综述了近２０年来自浮颗粒的固液两相悬浮和气液固三相分散的研究结果,并与下沉颗粒体系的规律作了比较,发现自浮颗粒三相分散规律与下沉颗粒的三相分散规律存在奶多差别。前者的悬浮难点在液面,要求搅拌浆能提供液面是上推式的流型,而后者的悬浮难点在釜底,要求搅拌浆能提供釜底是下压式的流型。     

纳米羟基磷灰石的制备及表征

采用化学沉淀法制备了羟基磷灰石纳米粒子,并且通过扫描电子显微镜(SEM)、X射线衍射(XRD)、红外光谱(IR)等测试手段,对其进行了表征。实验结果表明:以Ca(OH)2和H3PO4为原料所制备出的纳米羟基磷灰石纳米粒子多呈针状或短棒状,平均粒径20~25 nm,长75~80 nm,且大小均匀,分散性好。尺寸和形状更接近人体骨磷灰石结构,并能与骨形成牢固的化学结合,是一种很有应用前景的人工骨和人工口腔材料。     

混合机在浮法玻璃生产线窑头料仓的应用

在配合料进入窑头料仓前增加小型混合机,混合生料与熟料,增加碎玻璃与混合料的均匀度,解决混合料分层问题,使混合料均化后布入料仓,以提高玻璃原料熔化质量,为后续工序提供生产高质量、高产量玻璃的基础。     

串联密炼机组的研发和应用概况

介绍串联密炼机组的研发和应用概况。串联密炼机组由带压砣的上位机与不带压砣的大容量下位机组成,上位机采用低温转子,下位机采用啮合型转子。串联密炼机组可以实现从原材料投入到终炼胶产出连续一步完成,尤其适用于白炭黑用量大的胶料混炼,可提高混炼质量和生产效率,降低混炼能耗。大连橡胶塑料机械股份有限公司串联密炼机组的结构设计重点:密炼室和转子、传动系统、液压式压砣、冷却系统和过渡翻板门等;系统控制要点:密炼室温度和冷却效果、转子无级调速和压砣位置无级调整等。     

宽粘度域搅拌器的开发及其研究进展

考虑到过程工业中诸多混合体系的变粘特性以及传统搅拌器应用范围的局限性,研究开发宽粘度域搅拌器很有必要。在介绍单一叶片式和双轴组合式宽粘度域搅拌器类型、结构特点和应用范围的基础上,概述了其性能研究的国内外进展,分析了各宽粘度域搅拌器的优、缺点。最后对单一叶片式和双轴组合式宽粘度域搅拌器进行了比较,明确了发展趋势,并指明宽粘度域搅拌器的选用应兼顾体系物性的变化、设备结构的复杂程度、功率及混合特性等因素。     

XPS and SIMS characterization

XPS study V₂O₅–WO₃/TiO₂ mixed oxide catalysts for Selective Catalytic Reduction (SCR) of NO_x carried out by researchers from ten different laboratories shows good reproducibility of the chemical shift results. The binding energies of the corresponding core level spectra allow us to identify the chemical states of main elements as Ti(IV), V(V) and W(VI). No other oxidation states for these elements were observed both for fresh/used and for crushed/monolith samples. Discrepancy in quantitative data can be proposed to arise from the heterogeneity of their composition as a function of depth. This suggestion is confirmed by SIMS data and ion etching experiments which indicate surface location of V₂O₅ phase, as well as impurity ones, with respect to TiO₂ and WO₃ and their redistribution as result of catalyst operation.     

湖北竹溪生漆发展探析

湖北竹溪位于秦巴山区中部,是全国生漆主产县,也是传统出口商品,大毛叶漆树是其优良品种。生漆作为竹溪的主导产业,解决发展的路径,帮助农民脱贫致富,本文进行初步的探讨。     

混炼设备的发展

在高分子成型加工领域，混炼是决定高分子制品性能的重要环节，混炼设备的发展经历了下列几个主要阶段；开炼机、密炼机、单（ 双）螺杆挤出机和双转子连续混炼机。笔者综述了主要混炼设备的特点及应用现状，并对炼设备的发展做了预测。     

对氟苯甲脒杀菌剂的新型合成方式与表征

以对氟苯甲腈为原料进行了对氟苯甲脒合成反应的研究。采用新的合成方法使脒基化反应不需要通入干燥的氯化氢气体,对环境友好,无污染,并取得了较高的产率,操作方法简单易行。通过实验确定了最佳反应时间、最佳反应温度以及最佳物料之间的配比。     

Synthesis and characterization of two PbO-chromium oxides

PbCrO₄ and Pb₂CrO₅ have been selectively synthesized via a chemical gas-liquid precipitation process by adjusting the pH value. The structure, size and morphology of the as-synthesized products are characterized by X-ray diffraction and transmission electron microscopy. Differences in UV-Vis spectra are related to differences in size and morphology.