Teflon PTFE emulsions

Method of Fabrication. The electrocatalyst, in the form of fine powder (15), can be produced by the Adams method (18). It is first mixed with PTFE emulsion solution such that the catalyst/PTFE ratio is 80 20 (19). The mixture is placed on a metal foil and sintered at 345 for more than one hour (20). After cooling, the Teflon-bonded catalyst is transferred from the foil to the membrane. The sintering process can be... 

Lafosse [342] described an oxidant-sorption method for synthesis of P(Py)/Teflon (PTFE) composites. A commercially available, surfactant-stabilized PTFE emulsion is mixed with aqueous Fe(III)-tosylate (oxidant-cum-dopant). Pyrrole is then added to this, yielding a finely divided P(Py)/PTFE composite after several h, precipitated with ethanol. SEM analysis showed the composite to be particles of 0.2 pm diameter which are presumed to be PTFE spherules coated with P(Py), rather than a homogeneous blend. Nevertheless, the composite showed conductivity of ca. 10 S/cm at a percolation threshold of ca. 16 v/v% P(Py), and acceptable microwave absorption properties. A similar emulsion method has been used by Sun and Ruckenstein [343] to synthesize P(Py)/Synthetic Rubber composites, with FeCl3 as oxidant, and several solvents (aqueous/organic combinations) and several nonionic surfactants being employed. Conductivities of the composites were ca. 3 S/cm, Tensile Strengths ca. 10 MPa, and Elongation at Breaks 38% to 166%. 

Poly(chlorotrifluoroethylene) (PCTFE, Kel-F fluoropolymer) is a thermoplastic semicrystalline polymer with (-CF2CCIF-) repeating units [49], Typically, PCTFE is synthesized via a free radical polymerization using bulk, suspension, or emulsion techniques [50]. Compared with PTFE (Teflon fluoropolymer), which has similar chemical properties, there is asymmetry in the CTFE monomer unit due to the presence of the chlorine atom in CFCl groups. Consequently, the NMR features of PCTFE are more complicated due to the possible monomer- and stereo-sequence variations. Since PCTFE has various distinguished properties, including thermal, chemical, and radiation resistance, low vapor permeability, and electrical insulation [51,52], it has... 

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