General properties table
Property | ASTM test | PTFE | PFA | FEP |
Physical properties | ||||
Specific gravity | D792 | 2.15 | 2.15 | 2.15 |
Water absorption ( % ) | D570 / 24 hrs 1/3" t | < 0.00 | 0.03 | < 0.01 |
Mold shrinkage ( cm / cm ) | 0.02 - 0.05 | 0.04 | 0.03 - 0.06 | |
Contact angle ( degree ) | Angle to level | 110 | 115 | 115 |
Thermal properties | ||||
Thermal conductivity ( cal/sec/cm2, ° /cm ) | C177 | 6 x 10-4 | 6 x 10-4 | 6 x 10-4 |
Coefficient of liner thermal expansion(1/°C) | D696 / 23 - 60°C | 10 x 10-5 | 12 x 10-5 | 8 - 10 x 10-5 |
Melting point (°C ) | 327 | 302 - 310 | 270 | |
Melt viscosity ( poise ) | 1011-1013 (340 -380°C) | 104-105 (380°C) | 4 x 104-105 (380°C) | |
Maximum tem for continuos use (°C / °F ) | 260 / 500 | 260 / 500 | 200 / 392 | |
Mechanical properties | ||||
Tensile strength ( kgf / cm2 ) | D638 / 23°C | 140 - 350 | 280 - 315 | 190 - 220 |
Elongation ( % ) | D638 / 23°C | 200 - 400 | 280 - 300 | 250 - 330 |
Compression strength ( kgf / cm²) | D695 / 1 % deformation, 25°C | 50 - 60 | 50 - 60 | 50 - 60 |
Tensile modulus ( kgf / cm² ) | D638 / 23°C | 4,000 | 3,800 | 3,500 |
Flexural modulus ( kgf / cm2 ) | D790 / 23oC | 5,000 - 6,000 | 6,600 - 7,000 | 5,500 - 6,500 |
Impact strength ( ft - lb / in ) | D256 / 23°C, Izod | 3.0 | No breakdown | No breakdown |
Hardness ( Shore ) | Durometer | D50 - D65 | D60 | D55 |
Deformation under load ( % ) | D621 / 100°C, 70 kgf / cm², 24 hrs D621 / 25°C, 140 kgf / cm², 24 hrs | 5.0 7.0 | 2.4 2.7 | 5.0 3.0 |
Static friction coefficient | Coated - steel surface | 0.02 | 0.05 | 0.05 |
Electrical properties | ||||
Dielectric constant | D150 / 103Hz D150 / 106 Hz | 2.1 2.1 | 2.1 2.1 | 2.1 2.1 |
Dielectric dissipation factor | D150 / 103 Hz | < 1 x 10-5 | 1 x 10-5 | 6 x 10-5 |
Dielectric break down strength ( V / mil ) | D149 / Short time, 1/8 in | 480 | 500 | 500-600 |
Volume resistivity( ohm - cm ) | D257 | > 1018 | > 1018 | > 1018 |
Chemical resistance | Excellent | Excellent | Excellent | |
Weather ability | Excellent | Excellent | Excellent | |
Combustibility ( % ) | D2863 / Oxygen concentration index | > 95 | > 95 | > 95 |
(PTFE = Polytetrafluoro ethylene, PFA = Perfluoro alkoxy, FEP = Fluorinated ethylene propylene)