Collaborative Research: Connecting the Wetting and Rheological Behaviors of Compatibilized Polymer Droplets in Immiscible Polymer Melts

合作研究：将不混溶聚合物熔体中增容聚合物液滴的润湿和流变行为联系起来

• 批准号: 0706432
• 负责人: Timothy Long
• 金额: $ 11.1万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0706432&HistoricalAwards=false
• 关键词: Collaborative; Research; Connecting; Wetting; Rheological

TECHNICAL SUMMARY:The objective of the research is to elucidate and quantify how the wetting of diblock copolymers governs the dispersion of polymer droplets in immiscible polymer blends. Specifically, monodisperse polydimethylsiloxane-polyisoprene (PDMS-b-PIP) diblock copolymers will be synthesized, and these components will be added to immiscible blends of PDMS and PIP to formulate of well-defined model systems of PDMS/PMDS-b-PIP/PIP. The advantage of using these systems is that the coalescence of the droplets, which depends on the amount of copolymer at the droplet interface, can be studied in either the PDMS or PIP matrices, which are both melts at room temperature. The use of these components will help to establish whether wetting phase diagrams, which depend on the chain lengths of the block copolymers and matrix polymers, can be used to predict the rheology of the immiscible droplets. Specifically, can theoretically derived diagrams predict the regions over which droplets are unstable and coalesce or are stable and disperse? To explore this question, well-controlled rheological experiments will be performed on the model systems, and the results of these experiments will be compared to theoretical predictions of the rheological behavior of immiscible droplets in polymeric media. It is expected that the results of this research will enhance the understanding into the mechanisms that control the dispersion of polymer droplets into polymer melts. These findings should positively impact the production of engineered materials whose properties are optimized when the droplets are evenly dispersed throughout the blend. NON-TECHNICAL SUMMARY:Tremendous opportunities exist for researchers to create advanced, lightweight materials from immiscible polymer blends made compatible with block copolymers. Copolymers, containing blocks chemically identical to the blended components, segregate to the interface between the polymers, which should produce a fine dispersion of one polymer in another. However, fine dispersions are rarely achieved in practice, because the droplets tend to coalesce, weakening the performance of the blends. To resolve this issue, researchers from the University of Virginia (UVa) and Virginia Polytechnic Institute (VPI) will collaborate. They will synthesize and formulate systems of immiscible polymers and block copolymers of academic and industrial interest, and investigate the dispersion characteristics of these systems in well-controlled experiments. A central thrust of the research is to determine whether theoretically derived phase diagrams can be used to predict the regions over which the droplets coalesce or disperse. Preliminary findings of the collaborators indicate that phase diagrams do aid in the prediction of droplet coalescence and dispersion. Funding from the NSF will be used to cement these relationships, which are important because they can be used to provide user-friendly roadmaps to engineer advanced materials such as automotive parts, medical fabrics, and insulation products. Moreover, broader impacts from the research include using the results to enhance a course on interfacial chemistry and reaching out to local schools with the goal of increasing the number and diversity of qualified engineering and science applicants to UVa and VPI.

技术摘要：该研究的目的是阐明和量化二嵌段共聚物的润湿如何控制聚合物液滴在不混溶聚合物共混物中的分散。 具体来说，将合成单分散聚二甲基硅氧烷-聚异戊二烯（PDMS-b-PIP）二嵌段共聚物，并将这些组分添加到PDMS和PIP的不混溶混合物中，以配制明确的PDMS/PMDS-b-PIP/PIP模型系统。使用这些系统的优点是，液滴的聚结取决于液滴界面处共聚物的量，可以在 PDMS 或 PIP 基质中进行研究，这两种基质都在室温下熔化。这些组分的使用将有助于确定润湿相图（取决于嵌段共聚物和基质聚合物的链长）是否可用于预测不混溶液滴的流变性。 具体来说，理论上得出的图表能否预测液滴不稳定并聚结或稳定并分散的区域？ 为了探索这个问题，将对模型系统进行良好控制的流变实验，并将这些实验的结果与聚合物介质中不混溶液滴的流变行为的理论预测进行比较。 预计这项研究的结果将加深对控制聚合物液滴分散到聚合物熔体中的机制的理解。这些发现应该会对工程材料的生产产生积极影响，当液滴均匀地分散在混合物中时，工程材料的性能就会得到优化。 非技术摘要：研究人员有巨大的机会利用与嵌段共聚物相容的不混溶聚合物共混物来制造先进的轻质材料。含有与共混组分化学性质相同的嵌段的共聚物在聚合物之间的界面上分离，这应该产生一种聚合物在另一种聚合物中的精细分散体。 然而，在实践中很少实现精细分散，因为液滴往往会聚结，削弱共混物的性能。 为了解决这个问题，弗吉尼亚大学 (UVa) 和弗吉尼亚理工学院 (VPI) 的研究人员将进行合作。 他们将合成和配制具有学术和工业意义的不混溶聚合物和嵌段共聚物系统，并在良好控制的实验中研究这些系统的分散特性。 该研究的中心目标是确定理论上得出的相图是否可用于预测液滴合并或分散的区域。 合作者的初步研究结果表明，相图确实有助于预测液滴聚结和分散。 美国国家科学基金会的资金将用于巩固这些关系，这很重要，因为它们可以用来提供用户友好的路线图来设计先进材料，如汽车零部件、医用织物和绝缘产品。 此外，该研究的更广泛影响包括利用研究结果来加强界面化学课程，并接触当地学校，以增加 UVa 和 VPI 合格工程和科学申请者的数量和多样性。