Thermotropic Liquid Crystalline Polymer Fibers

Super-strength, lightweight materials used in bullet-proof vests, high-performance cables and tires, and stealth airplanes are built from liquid crystalline polymer (LCP) fibers. The remarkable strength properties are dominated by molecular alignment achieved as a result of the complex interactions at play in fiber processes. The fiber manufacturing process begins with a high temperature liquid phase of rigid rod macromolecules, whose orientation couples to the strong elongational free surface flow. The flow exits at a prescribed radius and velocity ($v_0$), tapers and cools as it evolves downstream, and solidifies along some free boundary, below which a take-up velocity ($v_1 > v_0$) is imposed at a fixed location. Our goal in this paper is a model for this process which realistically couples the hydrodynamics, the LCP dynamics, and the temperature field, along with the free surface and boundary conditions. Moreover, we aim for a model, by necessity complex, that provides nontrivial fiber process predict...

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