Molecular Modeling of Failure in Polymer Nanocomposites

聚合物纳米复合材料失效的分子模拟

• 批准号: 1536914
• 负责人: Robert Riggleman
• 金额: $ 32.53万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536914&HistoricalAwards=false
• 关键词: Molecular; Modeling; Failure; Polymer; Nanocomposites

The availability of light, strong and tough materials is essential for advances in modern engineering and to the technological future of society. Nanocomposite materials consisting of a polymer matrix with distributed nanoparticles are of current interest. These materials can provide significant property improvments relative to the pure polymer. Yet, current continuum mechanics based theories are unable to explain these findings. This award is concerned with fundamental research on the mechanisms that lead to the desireable properties of polymer matrix nanocomposites. The anticipated outcomes of this award will thus allow materials engineers for further advances the science and engineering of nanocomposites and contribute to the general goals of the Materials Genome Initiative. The award also supports associated educational and outreach activities.This award supports research with the goal to uncover how plastic deformation originates, or terminates, near a nanoparticle surface and leads to the formation of shear bands. For amorphous solids it has recently been demonstrated that regions prone to irreversible deformation can be detected from the examination of their internal low frequency vibrational modes. The modes that comprise the so-called boson peak excite the soft regions in the material, or the regions that are most likely to fail under applied load. The present work will begin by characterizing the distribution of these modes around a nanoparticle placed in a model polymer matrix as a function of the particle size and interaction energy with the matrix. Then, a recent computational polymer model exhibiting a ductile-to-brittle transition, the study will investigate how the nanoparticles lead to failure in a pillar geometry. Finally, the goal is to computationally engineer various surface chemistries to enable an ultimately tougher polymer nanocomposite material.

轻质、坚固且坚韧的材料对于现代工程的进步和社会的技术未来至关重要。由具有分布纳米颗粒的聚合物基质组成的纳米复合材料是当前人们关注的焦点。相对于纯聚合物，这些材料可以提供显着的性能改进。然而，当前基于连续介质力学的理论无法解释这些发现。该奖项涉及对聚合物基纳米复合材料产生理想性能的机制的基础研究。因此，该奖项的预期成果将使材料工程师能够进一步推进纳米复合材料的科学和工程，并为材料基因组计划的总体目标做出贡献。该奖项还支持相关的教育和外展活动。该奖项支持旨在揭示塑性变形如何在纳米颗粒表面附近发生或终止并导致剪切带形成的研究。对于非晶固体，最近已经证明，可以通过检查其内部低频振动模式来检测容易发生不可逆变形的区域。构成所谓玻色子峰的模式会激发材料中的软区域，或者在施加的负载下最有可能失效的区域。目前的工作将首先表征放置在模型聚合物基质中的纳米颗粒周围的这些模式的分布，作为颗粒尺寸和与基质的相互作用能的函数。然后，最近的计算聚合物模型表现出延性到脆性的转变，该研究将研究纳米粒子如何导致柱几何结构失效。最后，目标是通过计算设计各种表面化学，以实现最终更坚韧的聚合物纳米复合材料。