| 摘要 |
<p>The present invention provides for a method of cold drawing polymeric yarns suitable for use in implantable medical devices, such as vascular grafts. The method of the present invention produces cold drawn polymeric yarns that have a substantially uniform linear density and a highly oriented molecular structure as well as good lubricity, nonthrombogenicity and biocompatibility. In one embodiment of the present invention there is provided a method of cold drawing multi-filament PTFE yarns include the steps of maintaining the PTFE yarn at a temperature below the glass transition temperature of the yarn, drawing the yarn at such temperature over a first roller rotated about its axis at a first speed and a second roller rotated about its axis at a speed faster than the speed of the first roller to a selected denier and to increase molecular orientation; and twisting the drawn yarn.</p> |
