Gel-size dependence of temperature-induced microphase separation in weakly-charged polymer gels

The gel-size dependence of microphase separation in weakly-charged gels of N-isopropylacrylamide (NIPA) and 1-vinylimidazole (VI) copolymers has been investigated using swelling measurement, small-angle neutron scattering (SANS), and dynamic and static light scattering (DLS/SLS). It is known that weakly-charged polymer gels undergo microphase separation in a poor solvent as a result of competing interactions involving hydrophobic attraction versus electrostatic repulsion. The microphase separation is characterized by a scattering maximum in SANS intensity functions of which Bragg spacing, Λ, is around 20-30 nm. However, when gel size was reduced to the order of Λ, no microphase separation was observed. Instead, a typical scattering of isolated spherical particles was clearly observed. On the basis of the experimental evidence, we conclude that microphase separation has its own wavelength independent of gel size, and nanometer-order gels, i.e., nanogels, do not undergo microphase separation.     

Silane functionalization of perfluoroether oligomers for reaction management and morphology control of two‐phase epoxy networks

Mixtures of an epoxy resin, hardener, and acid functionalized perfluoroether oligomers will readily undergo phase separation during curing. However, the conditions to bring about the growth of nuclei into microscopic particles have hitherto been found only for systems cured with anhydrides. In the present study perfluoroether oligomers were functionalized by established procedures to introduce both carboxylic acid groups and alkoxysilane groups in sites within the chain extended segments. The presence of alkoxysilane groups together with the prereaction step with an excess epoxy resin, prior to the addition of the aromatic amine hardener, induced phase separation by a nucleation‐and‐growth mechanism. The dual functionality in the perfluoroether oligomer was even more beneficial when the alkoxysilane groups were hydrolyzed prior to the addition of the amine hardener. Under such circumstances the precipitation of the perfluoroether oligomer occurred quantitatively, as indicated by the complete absence of any plasticization effects in the epoxy matrix. From electron microscopy examinations, thermal analysis, and measurements of mechanical properties it was possible to deduce a plausible mechanism for the formation of the typical core‐shell aggregates within the precipitated particles for these systems, which could also be applied to other systems, such as those using carboxylic‐acid‐terminated butadiene acrylonitrile oligomers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1036–1049, 2005     

用唐钢石人沟铁精矿生产超级精矿

以石人沟铁矿精矿粉为原料生产超级铁精矿，进行了磨矿—反浮选、分级—反浮选和分级—低磁场磁选等试验，并按磨矿—反浮选方案建成了生产超级铁精矿的选矿厂。实践证明阳离子反浮选是生产低硅高纯铁精矿的可靠工艺。     

断续流对旋流器油水分离效率影响的实验研究

目前,大部分井下油水分离的旋流器由地面游梁式抽油机通过抽油杆柱提供能量,这样进入旋流器流量产生断续现象。通过实验证明断续流流量的不连续性使旋流器油水分离效率下降5％以内,存在一定负影响;溢流含油浓度越高,断续流对旋流分离效率的负影响也越大,所以井下油水分离过程中,不能偏面追求过高的溢流口含油浓度,提高分流比F与入口含油浓度C_i比值,减小断续流对分离效率的影响。     

液固分离技术的进展

本文简述了液固分离技术近年来的进展。特别涉及加压电过滤设备、毛细吸附作用下的真空过滤机、动态过滤技术、新型卧式螺旋卸料沉降离心机、滤材等方面技术的国内外进展情况。     

构树皮丙酮抽出物的DEAE—Sephadex分离及GC—MS分析

利用ＤＥＡＥ—Ｓｅｐｈａｄｅｘ分离柱及ＧＣ—ＭＳ对构树皮丙酮抽出物 进行了分离和分析．在丙酮抽出物中中性组分占抽出物的５９．７％，弱酸性 组分和强酸性组分分别占２５．９％和１０．３％．中性组分中不皂化物占 ８９．２％，皂化物仅占８．４％．不皂化物的成分比较复杂，所检出的主要有 甾醇和甾酮类．皂化物中亚油酸占５０％，软脂酸占２１％．弱酸性组分中 ５０％以上是脂肪酸（亚油酸和软脂酸），而没有松香酸．     

聚丙烯微孔膜研究进展

聚丙烯（PP）是一种价格低廉的塑料，是目前最主要的制备高分子微孔膜的材料之一。笔者综述了近年来PP微孔膜制备方法的研究进展，重点介绍了熔纺拉伸法（MSCS）、热致相分离法（TIPS）、共混拉伸法、熔融烧结法等PP微孔膜的常用制备方法，并对相关的影响因素进行了讨论。     

油水乳液分离吸附材料的分离原理、构建方法和分离性能

采用吸附材料进行油水分离是经济且非常有效的方法。吸附材料主要有无机材料、合成高分子材料和天然有机纤维材料等。相比较而言，天然有机纤维材料为可再生生物质资源，来源广泛、生物降解性好，可有效防止二次污染，具有良好的发展潜力，备受关注。本文首先简要介绍了油水乳液稳定性的影响因素，然后综述了油水分离材料的分离原理、构建方法和分离性能等研究进展，并总结了油水乳液分离材料的表征及其分离性能的评价指标。特别地，重点总结了天然有机纤维基吸附材料分离油水乳液的研究进展。最后指出研究智能响应型天然有机纤维基油水乳液分离吸附材料是重要的发展方向。     

微波在化工过程中的研究及应用进展

与传统加热过程比较，微波辅助有机合成的优势在于加快反应速率、提高产率和改变化学选择性。研究者们将这种常规加热无法重现的现象称为非热效应，但关于非热效应的存在性一直争论不休，至今微波促进合成反应的作用机理尚不清楚。总结了微波技术在有机合成和化工分离过程的应用进展，综述了近年来国内外对微波热效应与非热效应的研究进展，阐述了微波效应的实例分析以及理论观点，同时，对微波在工业化过程的发展进行了分析与展望。     

液—液两相聚结分离原理及实际应用

对非均相液—液两相的聚结分离机理进行了阐述,以纤维类聚结介质为例,将聚结过程分为液滴捕集、液滴聚结和液滴沉降三个阶段。在聚结原理基础之上,对液—液聚结分离用的聚结材料进行分类,在此基础之上,详细介绍了目前应用比较广泛的液—液两相分离设备。最后指出液—液两相聚结分离技术及设备的发展方向。