Fundamental Mechanisms of Adhesion at the Fiber-Matrix Interface

纤维增强聚合物中纤维与基体的界面性质对复合材料的整体性能有很大影响。然而，这个界面上的交互细节并没有被很好地理解。改性界面可以极大地提高性能，这是确定无疑的，但粘附性的基本物理化学机制及其与性能的关系尚未建立。粘着相互作用的三种主要机制被认为是机械相互作用、分子间相互作用和化学结合。研究人员的初步工作表明，少量共价连接到纤维表面的吊链显著增加了纤维与基质之间的粘附力。设计了一个实验程序，通过系统地用侧基修饰芳纶纤维的表面来研究粘附力增加的确切原因，这些侧基的化学结构提供了与基质发生不同的物理化学作用的可能性。这项研究的一个关键阶段是通过定量染料分析、非辐射荧光能量转移和连续润湿力测量来实验确定表面和侧基的确切状态。结果将与粘合数据相关联，以描绘分子水平、界面细节和界面粘合之间的关系。就美国工业未来的国际竞争力而言，没有比先进复合材料领域更重要的研究领域了。纤维复合材料的性能由基质、纤维以及它们相互作用的界面决定。了解和控制这种界面对于我们设计复合材料以实现其全部潜力的能力至关重要。

The nature of the interface between the fiber and matrix in fiber- reinforced polymers greatly influences overall performance of the composite material. The details of the interactions at this interface are not well understood, however. It is firmly established that modifying the interface can greatly improve performance, the underlying physicochemical mechanisms of adhesion and their relationship to performance have not been established. The three main mechanisms believed to underly the adhesive interaction are mechanical interactions, intermolecular interactions, and chemical binding. Preliminary work by the investigator has shown that a small number of pendant chains covalently attached to a fiber surface significantly increases adhesion between fiber and matrix. An experimental program has been designed to examine the exact cause of the increased adhesion by systematically modifying the surface of Aramid Fibers with pendant groups whose chemical structure provides varying potential for physicochemical interaction with the matrix. A key phase of the research is experimental determination of the exact state of the surface and the pendant groups by means of quantitative dye analysis, nonradiative fluorescence energy transfer, and continuous wetting force measurements. Results will be correlated with adhesion data to delineate the relation between molecular level interfacial details and interfacial adhesive bonding. There is no more important area of research, relative to the future international competitiveness of American industry, than the area of advanced composite materials. The properties of a fiber composite are determined by the matrix, the fiber, and the interface at which they interact. Obtaining understanding and control of this interface is crucial to our ability to engineer composite materials so as to realize their full potential.