纳米石墨在非水介质中的分散

改变超声工艺条件、分散介质、分散剂及其用量来改善纳米石墨在非水介质中的分散稳定性,并通过测试含纳米石墨悬浮液的稳定时间、黏度及吸光度,表征纳米石墨在分散介质中的分散状态。研究结果表明,最佳超声条件:30℃,20—25min;二甲基硅油为最佳分散介质,纳米石墨质量分数为0.03%,钛酸酯偶联剂NDZ-105为最佳分散剂,其最佳添加质量分数为2%。     

在盐水介质中用分散聚合法合成阳离子聚丙烯酰胺

在盐水介质中，以PA-01为分散稳定剂，采用分散聚合法合成了高分子量的阳离子聚丙烯酰胺。考察了单体浓度、分散稳定剂浓度、硫酸铵浓度、引发剂用量、反应温度对分散聚合的影响，并选定合成稳定、特性黏数较大的分散聚合物PDA的条件。结果表明，最佳的实验条件：PA-0l的质量分数为2％；引发剂的用量为1．5×10^-4 mol／L、温度为45℃，单体质量分数为25％；硫酸铵的质量分数为30％。     

丙烯酸分散聚合制备吸水凝胶

以氯化钠(Na Cl)水溶液为分散介质,过硫酸钾(KPS)为引发剂,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,聚乙烯吡咯烷酮(PVP)为分散剂,通过分散聚合制备了聚丙烯酸钠(PAA-Na)吸水凝胶。考察了单体中和度,引发剂用量、交联剂用量、分散剂用量对分散聚合的分散效果及凝胶吸水性能的影响。实验结果表明,当盐水浓度为24 wt%,丙烯酸中和度为75%,引发剂、交联剂、分散剂用量分别占单体0.9 wt%、0.6wt%、12 wt%时,制备的吸水凝胶能够稳定分散且吸水效果较好。     

两性聚丙烯酰胺“水包水”乳液的制备

以丙烯酰胺(AM)和两性单体N,N-二甲基(甲基丙烯酰氧乙基)氨基丙磺酸内盐(DMAPS)为聚合单体,聚甲基丙烯酰氧乙基三甲基氯化铵(PDMC)为分散稳定剂,2,2'-偶氮(2-脒基丙烷)二盐酸盐(V-50)为引发剂,在硫酸铵水溶液中通过分散聚合制备两性聚丙烯酰胺(AmPAM)"水包水"乳液。考察了分散剂用量、无机盐用量、单体质量分数及其摩尔比和引发剂用量等对分散聚合的影响,其最佳反应条件为:硫酸铵质量分数22.3%～27.4%、分散剂用量为0.195～0.248 g/g(monomer)、单体摩尔比n(AM)∶n(DMAPS)=9∶1、单体质量分数为14%、引发剂用量为4.5×10-4g/g(monomer)。采用红外光谱(FTIR)和核磁共振氢谱(1HNMR)对聚合物结构进行了表征。     

阳离子聚丙烯酰胺水分散液的合成研究

概述了分散聚合的特点及其机理,重点介绍了以水为介质的阳离子聚丙烯酰胺分散聚合研究进展。详细探讨了阳离子聚丙烯酰胺水分散聚合体系的组成,即单体、分散介质、分散剂、引发剂等因素对分散聚合的影响以及各组分之间的相互关系。     

非极性混合介质中分散聚合法制备聚乙烯基吡咯烷酮

以乙烯基吡咯烷酮(NVP)为单体,环己烷的混合溶剂为分散介质,AIBN为引发剂,SEBS为分散剂,采用分散聚合的方法制备了分散性能好、粒径为1μm左右、热稳定性较好的聚乙烯基吡咯烷酮。考察了单体含量、引发剂用量、分散剂用量对分散聚合反应的影响。结果表明,转化率和分子量均随单体含量增加而增大,随引发剂的量的增大而减小;且在单体含量为30%、AIBN的用量为0.5%,分散剂用量为10%时,所合成的聚合物分子量最大。     

超临界二氧化碳中的分散聚合

在介绍以超临界二氧化碳(Sc-CO2)为介质的分散聚合的成粒机理的基础上,阐明分散剂在分散聚合中的稳定作用,着重综述分散剂的结构组成及用量对分散聚合树脂颗粒特性、聚合速率、产物分子量及分布等的影响,并展望Sc-CO2中分散聚合的研发和应用。     

杀螺胺乙醇胺盐水悬浮剂分散剂的筛选

[目的]筛选杀螺胺乙醇胺盐水悬浮剂分散剂。[方法]采用流点法和激光粒度测定法确定分散剂的种类,在该基础上通过黏度法确定分散剂的用量。[结果]聚乙烯吡咯烷酮PVP是杀螺胺乙醇胺盐水悬浮剂的合适分散剂。[结论]PVP为K15时,最佳使用量为0.5%~2.5%,PVP为K30时,最佳使用量为0.5%~1.5%。     

单分散甲基丙烯酸甲酯-苯乙烯共聚物微球的制备与表征

以聚乙烯吡咯烷酮(PVP)为分散剂,偶氮二异丁腈(AIBN)为引发剂,乙醇/水混合溶剂为分散介质,用分散聚合方法制备出微米级甲基丙烯酸甲酯-苯乙烯共聚物微球.研究了分散介质组成、单体质量比、分散剂用量、反应温度等反应条件对聚合产物粒径及粒径分布的影响.并用红外光谱对产物结构进行了表征.     

分散聚合法制备彩粉的粒径调控

采用分散聚合的方法制备出一种粒径在2～5μm之间,表面光滑、窄分布的彩粉.研究了引发剂、分散剂用量、分散介质中乙醇/水的比例、初始单体比及石蜡用量对彩粉粒径及粒径分布的影响.     

水性介质中纳米金刚石分散行为研究

文章探讨了不同分散剂在分散纳米金刚石颗粒时的作用机制,包括静电位阻、空间位阻、静电-空间位阻协同机制;同时研究了不同分散剂、用量、分散时间以及搅拌时间等对纳米金刚石分散的影响。研究结果表明,在高能机械化学处理过程中,在机械力和表面活性剂、无机电解质等物质的共同作用下,纳米金刚石的表面官能团组成发生了明显的变化,从而导致颗粒表面电性发生改变,颗粒间斥力增大,颗粒更加亲水,从而使得颗粒可以在体系中保持稳定分散。     

有机改性蒙脱石在有机介质中的分散性研究进展

介绍了有机蒙脱石在聚合物纳米复合材料制备中的应用,采用阳离子、阴离子和非离子表面活性剂改性的有机蒙脱石在有机介质中的分散性能的研究,并探讨了有机蒙脱石在有机介质中的分散机理,最后对提高有机改性蒙脱石的分散性能在未来的研究方向进行了展望。     

有机改性蒙脱石在有机介质中的分散性研究进展

介绍了有机蒙脱石在聚合物纳米复合材料制备中的应用,采用阳离子、阴离子和非离子表面活性剂改性的有机蒙脱石在有机介质中的分散性能的研究,并探讨了有机蒙脱石在有机介质中的分散机理,最后对提高有机改性蒙脱石的分散性能在未来的研究方向进行了展望。     

分散介质对纳米二氧化硅分散体系流变性能的影响研究

测定了不同分散介质以及同一分散介质不同相对分子质量、不同温度下的纳米二氧化硅分散体系的流变性能并进行了比较,得出以下结论：随着分散介质相对分子质量的增加,分散体系的粘度增加,固液间氢键作用力减弱,分散体系所需临界剪切应力减小;当分散介质的相对分子质量提高到一定程度后,固液间氢键作用力更弱,加上分子链增长造成空间位阻效应,纳米二氧化硅难于以三维网状立体结构存在于分散介质中,不会出现先剪切变稀后剪切增稠的流变曲线。分散体系所处的温度越高,体系的粘度越低,剪切增稠所需临界剪切应力越大,剪切增稠效果越差,甚至不出现先剪切变稀再剪切增稠的流变曲线。因此选择合适的分散介质及分散温度对改善纳米二氧化硅分散体系的流变性能有积极作用。     

Rheology of cubic particles in a concentrated colloidal dispersion suspending medium

The flow behavior of mixtures of micron‐sized cubic particles suspended in a concentrated colloidal dispersion is investigated across a broad range of cubic particle concentrations. In the semi‐dilute regime, the qualitative shape of the dynamic moduli and flow curves reflect those of the underlying colloidal dispersion medium. These curves are superimposed with the underlying colloidal dispersion using shift factors that are found to be larger than those obtained in a recent study of suspensions of non‐colloidal spherical particles in the same colloidal dispersion medium. At higher concentrations of cubic particles, deviations from this shifting procedure are apparent. Scaling calculations suggest depletion interactions are responsible for the increase in the low shear viscosity and confinement of the underlying colloidal dispersion can be expected to enhance the shear thickening behavior at high shear stresses. The results of this study provide guidance for formulating suspensions through control of particle shape and mixture concentration. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1091–1101, 2017     

Stability of hydrogen peroxide in an emulsion with a solidified dispersion medium

Results of an experimental evaluation of the decomposition rate of hydrogen peroxide in an emulsion with a solidified dispersion medium are presented. Translated fromFizika Goreniya i Vzryva, Vol. 35, No. 4, pp. 122–123, July–August 1999.     

Selection of dispersants for the dispersion of carbon black in organic medium

The dispersion of the carbon black pigment in non-aqueous medium requires the use of dispersant additives. Two carboxylic dispersants of different chemical nature and molar masses have been investigated regarding this purpose. Their adsorption behavior has been evaluated by means of adsorption isotherms. The molecular interactions taking place at the surface have been inferred from IR and ¹³C RMN spectroscopies. The rheological behavior of the dispersions has considerably been improved by the presence of the copolymer dispersant of higher molar mass. It might adsorb at the surface by hydrogen bindings while taking a flat conformation with tails and possibly few loops that contributed to the steric stabilization of particles. The consequences of the deflocculation of the suspension on the colorimetric properties are an enhanced tinting strength and improved color stability.     

离子液体中PAM水凝胶颗粒的制备

以[BMIM]PF_6离子液体为反应介质,采用两步法,制备聚丙烯酰胺水凝胶颗粒,探讨了CaCl_2浓度及缓冲溶液的pH值对水凝胶颗粒吸水性能的影响。结果表明,CaCl_2溶液的浓度为3%时,分散所得的水凝胶颗粒数目较多、尺寸均一,吸水性能最好;缓冲溶液的pH值为3.0时,水凝胶颗粒的吸水率最大,并且具有pH敏感性。     

离子液体中PAM水凝胶颗粒的制备

以[BMIM]PF_6离子液体为反应介质,采用两步法,制备聚丙烯酰胺水凝胶颗粒,探讨了CaCl_2浓度及缓冲溶液的pH值对水凝胶颗粒吸水性能的影响。结果表明,CaCl_2溶液的浓度为3%时,分散所得的水凝胶颗粒数目较多、尺寸均一,吸水性能最好;缓冲溶液的pH值为3.0时,水凝胶颗粒的吸水率最大,并且具有pH敏感性。     

Bubble generation rules in microfluidic devices with microsieve array as dispersion medium

Microfluidic devices with microsieve array as the dispersion medium have been well recognized. However, few studies have been made on gas‐liquid two‐phase flow in microsieve dispersion devices. The bubble generation rules with single‐pore, radial‐array pores, axial‐array pores, and square‐array pores were systematically investigated. The rules of pore activation have been suggested by considering the capillary force, flow resistances of both dispersed phase and continuous phase. An empirical equation and a theoretical equation to predict the activation of pores in microfluidic devices were developed. An equation to correlate the average bubble diameter with parameter of channel structure, phase ratio, and Ca number of continuous phase was also developed. The strategy of design and scaling up for microsieve devices is proposed. Meanwhile, a device with dual‐size pores according to the rules derived is designed. This device achieved much better dispersion performance. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1663–1676, 2015