NANOCOMP: Integrated Hybrid Computational and Experimental Design and Processing of Polymer Nanocomposites

这笔赠款的主要目标是开发一种聚合物纳米复合材料加工的综合混合计算和实验方法，以期能够开发具有量身定制的功能结构和性能的材料。热塑性聚合物纳米复合材料是最有前途的新一代材料之一，具有潜在的高导热、高电导、高机械性能和良好的阻隔性能。然而，为了实现其承诺的潜力，在对其加工过程中的结构发展以及与最终产品性能的对应关系的理解方面仍然需要克服现有的差距。在实验上，这项研究将基于通过一种新型的样品采集装置跟踪材料在挤出机内加工时的形态和流变演变的能力，该装置除了在线旋转流变仪外，还允许在挤出机机筒沿线的任何点采集少量样品。在计算上，这项研究将集中在开发斯托克斯动力学和耗散粒子动力学软件代码，该软件代码可以准确地模拟复杂材料中纳米粒子分散体在真实工艺环境中的流动和结构特性。如果成功，这项研究将能够预测真实聚合物复合序列中热塑性聚合物纳米复合材料的最终分散状态和取向作为流动条件和纳米粒子特性的函数。此外，它不仅提供了制造具有更好的整体性能的部件的能力，而且还提供了沿其横截面或表面具有不同的机械、热、电或磁性能的能力，即解决了逆工程问题，即应该对部件的每个部分应用什么材料结构和加工条件来产生最终所需的性能。这些部件的潜在长期应用包括电磁屏蔽、差动隐身特性、改进的弹道性能和轻型复合材料结构等。

The main objective of this grant is to develop an integrated hybrid computational and experimental methodology of polymer nanocomposite processing, with a view to enable the development of materials with tailored functional structure and properties. Thermoplastic polymer nanocomposites are among the most promising new-generation materials, with potential high thermal and electrical conductivities, mechanical performance and improved barrier properties. In order to fulfill their promised potential, however, existing gaps in the understanding of their structure development upon processing and the corresponding relationships with the final product properties still need to be overcome. Experimentally, this research will be based on the capability to follow the morphology and rheological evolution of the materials upon processing inside the extruder by means of a novel sample collecting device that allows small sample quantities to be collected at any point along the extruder barrel, in addition to an on-line rotational rheometer. Computationally, this research will focus on the development of Stokesian Dynamics and Dissipative Particle Dynamics software codes that can simulate accurately the rheological and structural properties of nanoparticle dispersions in complex materials under flow, in real process environments.If successful, it is expected that this research will allow the prediction of the final state of dispersion and orientation of thermoplastic polymer nanocomposites for real polymer compounding sequences as a function of flow conditions and nanoparticle characteristics. Also, it will provide the capability to not only produce parts with better overall properties, but also with differential mechanical, thermal, electrical or magnetic properties along their cross section or surface, i.e., to solve the inverse engineering problem of what material architecture and processing conditions should be applied to each section of the part to yield the final desired properties. Potential long-term applications of these parts include, among others, electromagnetic shielding, differential stealth characteristics, improved ballistics and lightweight composite structures.