ECTFE polymerization

FIGURE Y13 UV-visible transmission spectrum on 50-pm thick polymeric films (ECTFE, ETFE) compared to 3-mm Solar glass. 

The most important interpolymers (e.g., copolymers, terpolymer, etc.) are those made with tetrafluoroethylene (ethylene tetrafluoroethylene polymer, ETFE) and chlorotrifluoroethylene (ethylene chlorot-rifluoroethylene polymer, ECTFE). These two polymers are generally produced by suspension or emulsion polymerization methods. There is resemblance between the polymerization technology of ETFE and ECTFE. Indeed, some of the same patent art could be studied to learn about the technology. This section and the next one present the polymerization of ETFE (Sec. 5.7) and ECTFE (Sec. 5.8). 

Ethylene (Et) and chlorotrifluoroethylene (CTFE) have been copolymerized (ECTFE) in aqueous and nonaqueous mediums. Aqueously, polymerization can be initiated by oxygen-activated triethylboron at low temperatures, by peroxides, and by radiation induced techniques. The earliest record of ECTFE polymeriza-... 

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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