| 摘要 |
<p>Highly unusual and useful novel high-performance, oriented, lowcrystalline, essentially heterocyclic structures, e.g. films, are prepared from certain novel and important process sequences. These structures, e.g. films(in the direction of orientation) and fibers, possess a unique combination of minimal shrinkage at high temperatures, after orientation, coupled with negligible coefficient of expansion over an unusually wide temperature range. These advantages are obtained in an orientation process by controlling and selecting;(a) the temperature of orientation or stretching; (b) the rate of orientation;(c) the ultimate percent of stretch in the final product; and (d) a relatively rapid quench.</p> |
