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Effects of Dispersant Molecular Structure on the Stabilization of Dispersions Against Agglomeration and Sedimentation

分散剂分子结构对分散体稳定性的影响，防止团聚和沉降

基本信息

批准号：
1706305
负责人：
David Corti
金额：
$ 30万
依托单位：
Purdue University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-11-01 至 2022-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1706305&HistoricalAwards=false
关键词：
Effects Dispersant Molecular Structure Stabilization

项目摘要

Many industrially important processes involve suspensions of particles in a liquid. These processes are often hampered by agglomeration of the particles and sedimentation of the aggregates. Process engineers take steps to prevent agglomeration and sedimentation by adding surfactants, compounds that lower the surface tension between two liquids or between a liquid and a solid, that coat the particles and inhibit their agglomeration. However, adding a surfactant can also change the bulk properties of the suspension and make it more difficult to process. This research project involves studying and alternative approach to preventing agglomeration and sedimentation without changing significantly the flow properties of the suspension. The idea is to find surfactants that spontaneously form molecular structures or assemblies in the liquid that prevent particle agglomeration, sedimentation, or both. The researchers are examining a broad array of surfactant-particle systems and determining the characteristics of the system that prevent agglomeration. The results will help enable process engineers in such industrial areas as paints and inks, pharmaceuticals, and cosmetics to design products that remain stable and maintain their beneficial properties over long periods of time. The project also involves students at all academic levels, including high school students, especially those from traditionally underrepresented groups, who are being recruited to participate in the project through Purdue's SEED program. The goal of this project is to screen, evaluate, and select surfactant dispersants for controlling agglomeration and sedimentation of suspended particles. The role of surfactant molecular structure on the formation of assemblies such as micelles and vesicles that can inhibit agglomeration and sedimentation of particles is being investigated. A broad array of surfactants are being examined including single and double hydrocarbon chains connected to single and double polar head groups. Anionic, cationic, and nonionic surfactants with carbon chain lengths from 8 to 16 are being studied. Characteristics of the particles, such as size, composition, density and concentration, is also being included in the study. Agglomerate size is being determined by dynamic light scattering and spectroturbidimetry, and changes in rheological properties are being measured using a constant stress rheometer. Cryo-transmission electron microscopy is being used when appropriate to characterize vesicle and particle structures. Computational studies using Brownian Dynamics and Stochastic Dynamics simulations are being carried out to identify mechanisms of suspension stabilization.

许多工业上重要的过程都涉及液体中颗粒的悬浮液。这些过程常常受到颗粒的附聚和聚集体的沉降的阻碍。工艺工程师采取措施通过添加表面活性剂来防止附聚和沉淀，表面活性剂是降低两种液体之间或液体与固体之间的表面张力的化合物，这些化合物覆盖颗粒并抑制其附聚。然而，添加表面活性剂也会改变悬浮液的整体性质并使其更难以加工。该研究项目涉及研究和替代方法，以防止结块和沉淀，而不显着改变悬浮液的流动特性。这个想法是寻找能够在液体中自发形成分子结构或组装体的表面活性剂，从而防止颗粒团聚、沉降或两者兼而有之。研究人员正在研究一系列广泛的表面活性剂颗粒系统，并确定该系统防止团聚的特性。研究结果将有助于油漆和油墨、药品和化妆品等工业领域的工艺工程师设计出能够长期保持稳定并保持其有益特性的产品。该项目还涉及所有学术水平的学生，包括高中生，特别是那些来自传统上代表性不足群体的学生，他们正在通过普渡大学的 SEED 计划招募参与该项目。该项目的目标是筛选、评估和选择用于控制悬浮颗粒的团聚和沉降的表面活性剂分散剂。表面活性剂分子结构在胶束和囊泡等组装体形成中的作用正在研究中，这些组装体可以抑制颗粒的团聚和沉降。正在研究一系列广泛的表面活性剂，包括连接到单极性头基和双极性头基的单烃链和双烃链。碳链长度为8至16的阴离子、阳离子和非离子表面活性剂正在研究中。研究还包括颗粒的特征，例如尺寸、成分、密度和浓度。通过动态光散射和分光比浊法测定附聚物的尺寸，并使用恒应力流变仪测量流变特性的变化。在适当的时候使用冷冻透射电子显微镜来表征囊泡和颗粒结构。正在进行使用布朗动力学和随机动力学模拟的计算研究，以确定悬架稳定的机制。