ECTFE is resistant to acids at high concentrations and temperatures, caustic media, oxidizing agents, and many solvents. Its chemical resistance is similar to that of PTFE.[1][2]Permeation of this polymer by large molecules is slow and thus is not relevant in final applications. Small molecules, however, may permeate through the polymer matrix. In lining or coating applications using ECTFE, permeability of certain small molecules determines the lifetime of anti-corrosion protection. Small molecules such as H2O, O2, Cl2, H2S, HCl, HF, HBr, N2, H2, and CH3OH are relatively mobile in the polymer matrix and lead to measurable effects.[3][4] Permeation resistance of the polymer is critical for lining and coating applications because permeating species may attack the underlying mechanical layers, such as fibre-reinforced plastic (FRP) or steel. High permeation resistance to small molecules is a consequence of the free volume occupied by the chlorine atoms in the polymer chain.
ECTFE has a continuous usage temperature range between –76°C and +150°C (–105°F to +300°F). It has strong impact resistance and a Young's modulus in the range of 1700 MPa,[5] allowing for self-standing items and pressure piping systems. The polymer maintains high impact strength in cryogenic applications.[6]
In terms of fire resistance, ECTFE shows a limiting oxygen index of 52%.[7] This value places it between the fully fluorinated polymers PTFE, PFA, and FEP with a limiting oxygen index of 95% and other partially fluorinated polymers like PVDF with a limiting oxygen index of 44% or ETFE with a limiting oxygen index of 30%.
Extrusion of ECTFE fabric-backed sheets and subsequent fabrication into vessels, pipes or valves is done in the chemical industry.[14][15][16] Thick sheets are compression molded and can be manufactured to 50mm in thickness. They are used in the semiconductor industry for wet benches or machining other parts.
The most common application of ECTFE is for corrosion protection, for which it is used in industries including:
Mining applications, in particular high pressure heap leaching
ECTFE has been widely used in the semiconductor industry for wet tool and tubing systems for lithographic chemicals.[25][26]
It is also used in the pharmaceutical industry.[27][28][29]
ECTFE is used for primary and secondary jacketing in specialty cables like data cables or self-regulating heating cables, applications where good fire resistance and electrical properties are key properties. It is also used for braiding in that field.[30][31]
ECTFE in the form of a monofilament fiber is used in flue gas treatment and in certain chemical processes.
Unlike PTFE, ECTFE can be crimped,[32] which allows its production in the form of nonwoven fibers with high surface area and porosity.[33] Even though such material has low chemical reactivity, ECTFE in general has somewhat lower chemical resistance compared to PTFE.[34]
