Fluoropolymer elastomer structures

Fluoropolymer elastomers (or Viton, a registered trademark of the DuPont Performance Elastomer LLC) consist of hexafluoropropylene (HFP), vinylidene fluoride (VDF), and tetrafluoroethylene. The 3M Corporation uses the trade name Fluorel. The structures of each of these monomers are shown in Figure 8.14. The fluorine content of these terpolymers is typically around 70% for Viton. Four basic types of this material are shown in Table 8.8 however, Viton Extreme comprises more types. 

The most common POM blends are homologous mixtures of POMs having different molecular structures (linear, branched, cross-linked) (Matsuzaki 1991), different molecular weights (Ishida and Sato 1970), or with different end groups (Nagasaki et al. 1991 Hanezawa and Ono 1991). On the secmid place are blends of POM with TPU, preferably polyester type. POMs are also blended with core-shell acrylic elastomers, MBS or MBA. Commercial blends of POM with PEST are available. To improve weatherability of POM, the resin was blended with PMMA and a fluoropolymer (viz. PTFE, PVF, PVDF) (Katsumata 1991). 

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