| 摘要 |
A graft is formed by extruding polymer to form a fibre and winding on a mandrel to form a nonwoven cylinder with overlying contacting fibres. An electrostatic charge is intermittently applied between extrusion orifice and mandrel, with the fibre accelerated onto the mandrel. At least some of the outer windings are applied in the absence of the charge after winding inner fibres with charge application so that a porous outer surface is formed to facilitate tissue ingrowth. Fibre breakage is monitored during winding and the charge is applied as soon as possible after breakage occurs in order to accelerate the broken end towards the mandrel to reattach the free end, removing the charge once the reattachment has occurred. The extruded fibre is pref. drawn, and is produced from a viscous soln. of polyurethane which gives bonding between overlying fibres. |
