Fluoropolymers classification

A classification by chemical type is given in Table 1. It does not attempt to be either rigorous or complete. Clearly, some materials could appear in more than one of these classifications, eg, polyethylene waxes [9002-884] can be classified in both synthetic waxes and polyolefins, and fluorosilicones in silicones and fluoropolymers. The broad classes of release materials available are given in the chemical class column, the principal types in the chemical subdivision column, and one or two important selections in the specific examples column. Many commercial products are difficult to place in any classification scheme. Some are of proprietary composition and many are mixtures. For example, metallic soaps are often used in combination with hydrocarbon waxes to produce finely dispersed suspensions. Many products also contain formulating aids such as solvents, emulsifiers, and biocides. 

In this entry, the classification, preparation, properties, fabrication, safety considerations, and economics of fluoropolymers are discussed. Monomer synthesis and properties have also been discussed. Increasing the fluorine content of a polymer increases chemical and solvent resistance, flame resistance, and photostability, improves electrical properties, such as dielectric constant, lowers coefficient of friction, raises melting point, increases thermal stability, and weakens mechanical properties. 

Classification Fluoropolymer Definition Thermoprocessable elastomer with exc. thermal props, and chem./solv. resist. 

Every molded part is different and so every mold is unique. Nevertheless, it is possible to distinguish some standard features and types. All are generally suitable for use with fluoropolymers. The principal types are two-plate, three-plate, and stack molds. A further distinction concerns the feed system, which can be either the cold or hot type. These classifications overlap. A three-plate mold will have a cold runner feed system, and a stack mold will have a hot ruimer system. Two-plate molds can have either feed system. 

Perfluoropolymers bum, but do not continue to bum when the flame is removed. All perfluorinated fluoropolymers pass a UL 83 vertical flame test and are classified 94 V-0 according to Underwriters Laboratory (UL) in their burning test classification for polymeric materials. Limiting oxygen index (LOI) by ASTM D2863 is 95% or higher for PTFE, PFA, FEP, and PCTFE. Partially fluorinated fluoropolymers are more flame resistant than other thermoplastics but not quite as resistant as the perfluorinated fluoropolymers, as evidenced by their lower EOI values. PVDF, ETFE, and ECTFE meet UE 94 V-0. Table 13.48 lists the EOI of various fluoropolymers. 

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