Pattern Formation in Polymer Solidification

结晶动力学一般由两个竞争现象控制，热力学驱动力迫使晶体/非晶体界面向前，以及熔化热和任何不可结合的组分从该界面流出的速度。在广泛的条件下，这种竞争导致界面呈现出复杂的模式。这项拟议工作的目的是开发一个实验基础和理论框架，通过它可以理解聚合物体系中这种图案的形成。这项工作将针对聚合物共混物中的球晶结晶和熔融纺丝纤维中微结构的发展。将进行静态结晶的实验计划。在这方面，将研究有约束的(通过温度梯度的强迫运动)和无约束的球晶状生长。在这两种情况下，都将测量微观结构参数，并将其与模型预测进行比较。同样，还将研究通过温度梯度结晶的取向聚合物纤维的温度和微晶半径。这些将与首席研究员开发的模型的结果进行比较。预计这项工作还将扩展现有的聚合物图案开发理论。

The kinetics of crystallization are, in general, controlled by two competitive phenomena, the thermodynamic driving force, which forces the crystal/noncrystal interface forward, and the rate at which the heat of fusion and any unincorporable components can flow away from that interface. Over a wide range of conditions, this competition causes the interface to assume intricate patterns. The aim of the proposed work is to develop an experimental base and a theoretical framework by which such pattern formation in polymer systems can be understood. This work will be directed at spherulitic crystallization in polymer blends and at the development of microstructure in melt-spun fibers. An experimental program for quiescent crystallization will be carried out. In this, both constrained (by forced movement through a temperature gradient) and unconstrained spherulite-like growth will be studied. In both cases, microstructural parameters will be measured and compared to model predictions. Likewise, a study will be made of the temperature and crystallite radius of oriented polymer fibers crystallized by running them through a temperature gradient. These will be compared to those of a model developed by the principal investigator. It is expected that the work will also extend existing theory for pattern development in polymers.