Fracture in Nanostructured Polymeric Materials

技术概要：本研究计划将探索嵌段共聚物的分子结构与所得纳米结构塑料的机械性能之间的联系。多嵌段共聚物将使用受控聚合技术合成，并通过化学改性（如催化氢化）来增强。这些化合物将以未稀释和混合形式进行研究。自组装成有序和无序的微相分离材料的特点是通过一个恭维的实验技术，如小角度X射线和中子散射，电子显微镜，动态力学光谱，和双折射分析。拉伸和冲击机械性能将进行评估，并与形态结构和分子结构。选定的嵌段共聚物和共混物样本将通过化学蚀刻或选择性溶剂萃取进行部分空隙化，从而产生纳米多孔整体块，并将对其进行断裂分析。将开发新的策略，通过多嵌段共聚物的设计，橡胶，玻璃状和半结晶嵌段的战略布局的基质materials.NON-TECHNICAL摘要：也许没有其他类别的材料性能有更大的影响，利用塑料比机械鲁棒性的组合，这些本质上脆弱的多孔化合物。该研究计划将探索由受控合成化学方法产生的聚合物分子的分子结构与所得材料的断裂行为之间的联系。这项工作将影响新塑料在重要商业产品中的应用，包括笔记本电脑屏幕等光学介质，可能用于燃料电池和电池的新型膜，以及广泛用于汽车工业的廉价轻质塑料。该计划提供了出色的机会，热情和通过在大学，当地学校和地区博物馆的互动节目告知学生在科学和工程教育的各个层次。

TECHNICAL SUMMARY:This research program will explore the connections between the molecular architecture of block copolymers and the mechanical properties of the resulting nanostructured plastics. Mutiblock copolymers will be synthesized using controlled polymerization techniques augmented by chemical modification such as catalytic hydrogenation. These compounds will be investigated in undiluted and blended forms. Self-assembly into ordered and disordered microphase separated materials will be characterized by a compliment of experimental techniques such as small-angle X-ray and neutron scattering, electron microscopy, dynamic mechanical spectroscopy, and birefringence analysis. Tensile and impact mechanical properties will be evaluated and correlated with the morphological structure and molecular architecture. Selected block copolymer and blend specimens will be partially voided by chemical etching or selective solvent extraction resulting in nanoporous monoliths that will be subjected to fracture analysis. New strategies will be developed to toughen these intrinsically fragile porous compounds, through a combination of multiblock copolymer design, strategic placement of rubbery, glassy, and semicrystalline blocks within the matrix material, and blending of multiblock copolymers with synergistic molecular architectures.NON-TECHNICAL SUMMARY:Perhaps no other class of material properties has a greater impact on the utilization of plastics than mechanical robustness. This research program will explore the connections between the molecular structure of polymer molecules, produced by controlled synthetic chemistry methods, and the fracture behavior of the resulting materials. This work will impact the application of new plastics in commercially important products ranging from optical media such as laptop computer screen, new types of membranes that may find uses in fuel cells and batteries, and inexpensive and light plastics used extensively in the automotive industry. This program affords outstanding opportunities to enthuse and inform students at all levels of education in science and engineering through interactive programs at the University, local schools, and regional museums.