CAREER: Research and Education on Multi-Scale Structure Development in Chaotic Mixing of Polymers

该学院早期职业发展（Career）奖侧重于聚合物材料在加工过程中多尺度结构演变的研究和教育。实验研究了在应变速率和温度可控的条件下，混相和非混相聚合物与纳米填料体系的混沌混合过程中，这些不断变化的结构对力学、电学和热性能的影响。混沌混合提供了以下非常理想的属性：(a)剪切和拉伸流动成分混合发生，(b)聚合物-聚合物或聚合物-填料界面区域以指数速率产生，在相同程度的混合下，能耗比传统挤压工艺低得多，(c)界面的反复拉伸和折叠形成自相似混合微观结构，显示嵌套条纹，液滴，或者一种聚合物在另一种聚合物中形成潜在的形态，这在传统的单螺杆和双螺杆挤出方案中是迄今为止无法实现的；(d)混合均匀性是通过保留自相似的微观结构来实现的，而不是传统的单螺杆和双螺杆挤出机的随机化。快速生成的界面面积将加速功能聚合物之间的反应，在反应处理和增容中，除了快速减少分散域的尺寸。所产生的自相似微结构将提供晶体/分散相的优选方向，以增强各向异性的电学、机械和化学性能，并将作为创造具有定制性能的聚合物产品设计的不寻常形态的工具。使用双转子混沌间歇混合器和连续混沌混合器进行的研究将产生低成本，快速和节能的混合技术，用于规模研究，现有产品的优化以及与工业合作伙伴合作的工艺开发。该教育项目将通过暑期研究和高级研究项目，以及参加研讨会和演讲，为高中生和本科生（包括少数民族学生）提供实践聚合物教育。将会为研究生和工业开设一门新的课程，内容是关于混沌混合在材料加工中的应用，这门课程将会从所提议的研究活动中得到大量的借鉴。此外，基于网络的课程模块将设计为流变学和聚合反应器工程，以达到传统课堂之外的更大的学生群体。

This Faculty Early Career Development (CAREER) award focuses on research and education on the subject of evolution of multi-scale structures of polymeric material during processing. The influence of these evolving structures on mechanical, electrical, and thermal properties in chaotic mixing of miscible and immiscible polymers and nanofiller systems under controlled conditions of strain rates and temperatures is experimentally investigated. Chaotic mixing offers the following highly desirable attributes: (a) mixing occurs by both shear and extensional flow components, (b) polymer-polymer or polymer-filler interfacial areas are created at exponential rates, with much less energy consumption for the same degree of mixing than in conventional extrusion processes, (c) self-similar mixing microstructures are formed by repeated stretching and folding of the interfaces, showing nested striations, droplets, or layers of one polymer in the other leading to potential morphologies so far not achieved in conventional single and twin-screw extrusion schemes and (d) mixing uniformity is achieved with retention of self-similar microstructures, as opposed to randomization in conventional single- and twin-screw extruders. Rapid interfacial area generation will expedite reactions between functional polymers in reactive processing and in compatibilization in addition to rapid reduction in dispersed domain sizes. The self-similar microstructures produced will offer preferred orientation of the crystallites/dispersed phases for augmentation of anisotropic electrical, mechanical, and chemical properties and will act as tools for creating unusual morphologies for design of polymer products with tailored properties. The study to be undertaken using twin-rotor chaotic batch mixer and continuous chaotic mixer will yield low cost, rapid, and energy-efficient mixing technology for scale-up studies, optimization of existing products, and process development in association with industrial partners. The education program will provide hands-on polymer education to high school and undergraduate students, including minority, through summer research and senior research projects and through participation in seminars and presentations. A new course will be developed on the applications of chaotic mixing in materials processing for graduate students and industry, which will draw heavily from the proposed research activities. In addition, web based course modules will be designed on rheology and polymerization reactor engineering to reach a much larger body of students outside conventional classrooms.