ECTFE (ethylene chlorotrifluoroethylene) is a polymer known for its chemical resistance, making it suitable for various industrial applications. It is resistant to acids at high concentrations/temperatures, caustic media,oxidizing agents, and manysolvents, similar toPTFE (polytetrafluoroethylene).[1][2] One of the key properties of ECTFE is itspermeation resistance to large molecules, which is generally slow and not significant in practical 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 asH2O,O2,Cl2,H2S,HCl,HF,HBr,N2,H2, andCH3OH are relatively mobile in the polymer matrix and lead to measurable effects.[3][4] This permeation resistance is particularly critical in lining and coating applications, where the material is used to protect underlying layers, such asfiber-reinforced plastic (FRP) orsteel, from corrosive substances. The polymer's resistance to permeation is attributed to the presence of chlorine atoms in the polymer chain, which occupies free volume and restricts the movement of small molecules through the material.
ECTFE finds applications in various industries due to its favorable chemical resistance properties, providing durable and reliable protection in harsh environments.
ECTFE has a continuous usage temperature range between –76°C and +150°C (–105°F to +300°F). It has strongimpact resistance and aYoung's modulus in the range of 1700MPa,[5] allowing for self-standing items and pressure piping systems. The polymer maintains high impact strength incryogenic applications.[6]
In terms of fire resistance, ECTFE shows alimiting oxygen index of 52%.[7] This value places it between the fully fluorinated polymersPTFE,PFA, andFEP with a limiting oxygen index of 95% and other partially fluorinated polymers likePVDF with a limiting oxygen index of 44% orETFE 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 50 mm 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 pressureheap 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 ofnonwoven fibers with highsurface area andporosity.[33] Even though such material has low chemical reactivity, ECTFE in general has somewhat lower chemical resistance compared to PTFE.[34]
