Filled PTFE

Fill PTFE squeeze bottles with the chemicals and label the bottles with a permanent marker. 

Because of its very low friction coefficient, PTFE is used for bearings, ball- and roller-bearing components, and sliding bearing pads in static and dynamic load supports.11 Piston rings of filled PTFE in nonlubricated compressors permit operation at lower power consumption or at increased capacities.12... 

Mitchell, D.C. and Pratt, G., Friction, Wear and Physical Properties of Some Filled PTFE Bearing Materials, Proc. Conf. on Lubrication and Wear, I.Mech.E., London, 1957. 

Other experiments were carried out with filled PTFE material, using steam as fluidizing gas. Fillers were carbon black, glass fibres, and bronze. Important parameters are listed in Table 24.10. In the first three experiments, the inflnence of the temperatnre was investigated, in the following were other fillers nsed. 

The highest yields of monomers such as TFE, HFP and C-C4F8 of aronnd 90 wt% were obtained at pyrolysis temperatures of between 645 and 600° C. Formation of oligomeric PTFE waxes can be explained by repolymerization of TFE in the cooling steps where the steam is condensed. The same phenomena occnr dnring indnstrial production of TFE. Carbon black and glass fibres have nearly no inflnence on the prodnct composition (compare Table 24.9). For the bronze-filled PTFE the yields of TFE, HFP and C-C4F8 were... 

Table 24.10 Parameters of the main pyrolysis experiments of filled PTFE pyrolysis...

Friction and wear of metal oxide filled PTFE can be improved by liquid paraffin lubrication, and the friction coefficient decreases by one order of magnitude. On the other hand, the interaction between liquid paraffin oil and metal oxide filled PTFE reduces load-carrying capacity because of absorption on the surface layers of composite. ... 

Polycomp . [ICIFluotopolymers] Polymer-filled PTFE conqx>sites for hi wear applies. 

Carbon reduces creep, increases hardness and elevates thermal conductivity of polytetrafluoroethylene. Wear resistance of carbon filled compounds improves, particularly when combined with graphite. Carbon-graphite compounds perform well in non-lubricated applications such as piston rings in compressor cylinders. Carbon-filled PTFE has some electrical conductivity. Close tolerances can be achieved... 

Filled PTFE—production techniques. Granular polytetrafluoroethylene compounds containing fillers are converted into parts by the same molding techniques as those used for neat resin. The compounding techniques aim at producing uniform blends of PTFE with fillers that can be processed in the same molding equipment. The rest of this section describes methods by which compounds can be made. 

Further reduction in deformation can be obtained by alternately inserting perforated stainless steel plates (Fig. 3.3) between the oriented sheets prior to sintering.The sintering process is conducted under pressure to consolidate the composite and obtain a predetermined thickness. At the end of sintering, the composite is cooled rapidly underpressure. PTFE actually bonds to stainless steel in this process. The decrease in creep is often substantial for example, by insertion of two steel plates, the creep relaxation of a silica-filled PTFE is decreased from 57.9% to 30.5% at 100°C.[i ]... 

Properties of granular PTFE compounds are presented in this section. A few points should be noted about filled PTFE compounds. Shape and size of the filler and resin particles, type of molding process, and processing conditions all influence the properties of parts made from compounds. Properties of compounds made with non-spherical particles are... 

Polytetrafluoroethylene has excellent chemical resistance properties. The effect of incorporation of additives on chemical properties depends on the t) e of the filler and the specific chemicals. In general, chemical properties of filled PTFE compounds are not as good as those of the unfilled resin. Table 3.21 shows the effect of a number of chemicals on car-bon/graphite, glass, and bronze compounds. 

Table 3.11. Mechanical Properties of Filled PTFE Compounds ...

Table 3.13. Deformation Under Load of Filled PTFE Compounds Measured According to ASTM D621A, Molding Direction ...

Figure 3.5 Effect of preforming conditions on the permeability of filled PTFE compounds.F i (Nitrogen permeability of...

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