Compare PCTFE and PEEK to identify the best option for your project

Differences Between PCTFE and PEEK

PCTFE is a fluoropolymer material with outstanding strength, stiffness, and dimensional stability. It has excellent chemical and radiation resistance and good flammability characteristics. PCTFE has a broad temperature range, good resistance to cold flow, and it has the lowest coefficient of thermal expansion of any unfilled fluoropolymer. 

PEEK (polyetheretherketone) is a high-performance engineering plastic with outstanding resistance to harsh chemicals, and excellent mechanical strength and dimensional stability. PEEK has a broad operating temperature range, offers hydrolysis resistance to steam, and maintains stiffness at high temperatures. 

PCTFE Material Characteristics
  • Broad chemical resistance
  • High purity
  • High compressive strength
  • Retention of ductility at cryogenic temperatures
  • Good resistance to creep (cold-flow) for a fluoropolymer
  • Relatively stable thermal expansion coefficient across temperature extremes
  • Very low gas permeability (excellent barrier properties)
  • Excellent flammability characteristics and oxygen compatibility
  • Good radiation resistance
PCTFE Applications:
  • Chemical processing components
  • Valve seats, seals, and gaskets
  • Chromatography columns
  • Liquid oxygen and liquid nitrogen valve linings
  • Moisture barriers 
PEEK Common Brands
  • Neoflon®, Kel-F®, Aclon®
PEEK Material Characteristics
  • Broad chemical resistance
  • Maximum service temperatures approaching 500°F
  • High strength, stiffness, and creep resistance to deformation at high temperatures
  • Excellent mechanical properties down to -85°F
  • Retention of ductility at cold temperatures
  • Excellent dimensional stability
PEEK Applications:
  • Semiconductor machinery components
  • Aerospace parts
  • Subsea parts
  • Down hole electrical connectors
  • Medical and pharmaceutical instruments
  • Food processing machinery components
  • Compressor, pump, and valve components
  • Bushings, bearings, seals, and back-up rings
  • Sterilizable by autoclave, dry heat, Et0, gamma irradiation, and electron beam
PEEK Common Brands
  • TECAPEEK®, SustaPEEK, Ketron®


Typical properties of PCTFE and PEEK
Specific gravity   D792 2.11 - 2.17 1.32
Water absorption
(immersion 24 hours)
% D570 0 0.50
Tensile strength psi D638 4,860 - 5,710 14,000
Elongation % D638 100 - 250 60
Izod Impact (notched) ft-lbs/in D256 2.5 - 3.5 1.6
Flexural strength psi D790 9,570 - 10,300 24,600
Flexural modulus psi D790 200,000 - 243,000 590,000
Dielectric strength (short term) v/mil D149 500 480
Coefficient of linear
thermal expansion
in/in/°Fx10-5 D696 3.9 2.6
Coefficient of friction (dynamic)     0.25
Max continuous service
temperature in air
°F   380°F 480°F
Hardness   Scale as noted
D785, D2240
Shore D 90 M105, R126,
Shore D 85

Values may vary according to brand name. Please ask your Curbell Plastics representative for more specific information about an individual brand.