NOVELTY - Processing of PTFE involves extruding a compounded PTFE resin with lubricating agent through an extruder along machine direction to form a PTFE ribbon extrudate, calendering the PTFE ribbon extrudate along the machine direction to form a planar layer of PTFE, selectively applying a stretching agent to the layer of PTFE in a predetermined pattern, providing a tentering machine, stretching the layer of PTFE in the tentering machine along transverse direction to the machine direction, and sintering the layer of PTFE.    USE - Processing of PTFE used for vascular graft (all claimed) for effectively treating diseased body passageways such as thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA), breast implant and drug delivery. Can also be used for tubing, protective clothing, sports equipment, filter, membrane, fuel cell, ionic exchange barrier and gaskets.    ADVANTAGE - The method enables efficient processing of PTFE layer with excellent productivity, increased porosity, and decreased density. The internodal distance between adjacent nodes in the microstructure is increased without affecting the thickness of the PTFE layer. The variable porosity of the outer surface of the graft is increased such that the tissue in-growth into the graft is improved.    DETAILED DESCRIPTION - Processing of PTFE involves extruding a compounded PTFE resin with lubricating agent through an extruder along machine direction to form a PTFE ribbon extrudate, calendering the PTFE ribbon extrudate along the machine direction to form a planar layer of PTFE having an upper surface and a longitudinal length in a machine direction of an extruder used to produce the layer of PTFE and having a width in a machine or transverse direction, selectively applying a stretching agent to the layer of PTFE in a predetermined pattern comprising a lateral zones (a) within the layer of PTFE which is saturated with the applied stretching agent and a lateral zone (b) within the layer of PTFE which is less than the applied stretching agent, providing a tentering machine, stretching the layer of PTFE in the tentering machine along transverse direction to the machine direction while the lateral zones (a) of the layer of PTFE are fully saturated with the stretching agent throughout thickness during stretching, and sintering the layer of PTFE. The compounded PTFE resin comprises polytetrafluoroethylene or polytetrafluoroethylene and a copolymer of polytetrafluoroethylene. The lateral zones (a) have a shape chosen from squares, rectangles, circles and ellipses, After stretching and sintering, the lateral zones (a) of the PTFE layer have no fluid permeability to low fluid permeability.    DESCRIPTION OF DRAWING(S) - The drawing shows schematic view of endovascular graft having a network of inflatable conduits.    Endovascular graft (150)    Proximal end (151)    Graft component section distal (152)    Graft component (153)    Inflatable cuffs (156)