Sintered PTFE

Table 3. Typical Mechanical Properties of Molded and Sintered PTFE Resins ...

Figure 1.6. Fracture surface of sintered PTFE showing a nearly hexagonal crystal viewed with its c-axis perpendicular to the plane of the micrograph. This crystal grew upon and perpendicular to a primary lamella, which is seen side-on and shows the curved edge profile associated with growth by nucleation and thickening. Magnification = 75,200, Scale bar = 0.5 pm.

To convert a dispersion into a sintered PTFE film, four distinct steps are required casting (dipping or flowing out) onto a supporting surface, drying to remove water, baking to remove the surfactant, and sintering to obtain a clear coherent film. 

Figure 10.18 SEM micrographs of the surface of an incompletely sintered PTFE tubing at magnifications of (a) lO.OOOX, and (b) 20,000X. (Courtesy of DuPont Fluoroplastics.)...

For processing after sintering, in the least expensive method for sintered PTFE tape or sheet, a large billet is skived on a lathe after it has been sintered and cooled. High precision articles are machined from ram-extruded rods. 

Procedures have been developed in which PFA has been welded to sintered PTFE. lf ] An example... 

Four polymers, POM, PA6.6, PTFE and PBT were tested. PA6.6 and PBT were injection moulded. POM was obtained as extruded sheet. PTFE was sintered. Measurements were performed with a sliding direction parallel to the injection moulding direction. The sliding direction was arbitrarily chosen in case of the extruded POM and sintered PTFE. Table I shows some characteristics of POM, PA6.6, PBT and PTFE [8]. 

Sintered PTFE 5-25 High cost, subject to element migration. 

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