March 08 2017 0Comment
pctfe

Typical Properties of Fluoropolymers

Property Method No. Units PTFE FEP PFA ETFE ECTFE PCTFE PVDF
Specific Gravity D792 2.17 2.15 2.15 1.74 1.7 1.7 1.78
Melting Point D2236 deg F
deg C
621
327
518
270
581
305
527
275
464
240
410
210
352
177
Tensile Strength D638
D1708
D1457
psi
MPa
2500
17
3400
23
4,000
27
6,960
48
6,960
48
6,060
41.78
7,830
54
Yield Strength D638 psi 1,450 1,740 2,250 3,480 4,500 5,800 6,670
Elongation % 200-500 250-350 300 200-500 200-300 80-250 20-150
Tensile Modulus D638 ksi 87 72.5 101.5 217.5 240 218 348
Flex Modulus D790 psi x 1000
MPa
98
675
101.5
700
95
655
203
1400
261
1800
333.5
2300
Izod Impact D256 ft-lbs/in
J/m
3.2
173
No Break No Break No Break 2-4
Hardness D2240 Shore D 60 57 62 75 75 90 79
HDT, @ 66 psi D648 deg F 250 158 164 219 240 248 300
HDT, @ 264 psi D648 deg F 122 129 118 160 169 239
Max. Cont Use Temp deg F
deg C
500
260
400
204
500
260
300
149
*Flame Rating UL 94 VO VO VO VO
Limiting Oxygen Index D2863 % >95 >95 >95 30-36
Thermal Conductivity Btu·in/h·ft2·°F
W/m·K
1.7
0.25
1.4
0.20
1.3
0.19
1.65
0.24
Dielectric Constant D150 1 MHZ 2.1 2.1 2.1 2.6
**Dielectric Strength D149 Volts/µm 18 53 80 79
Resistivity – Volume D257 ohm-cm >1018 >1018 >1018 >1017

PTFE Properties:

The Steel Industry and Chemical Processing Industry have been using fluoropolymer tubing products from materials like PTFE and hoses for many years for transferring highly caustic or corrosive chemicals. More and more, PTFE tubing is replacing carbon and other metal piping that deteriorates rapidly. Now and for the future, PTFE will continue to serve the industry in critical applications.

PTFE Thermal Qualities:
PTFE tubing can withstand temperatures up to 680 °F for limited periods of time.* Under cryogenic conditions, PTFE remains strong down to -320 °F.

*Above 500 °F, mechanical properties become a limiting factor

PTFE Electrical Qualities:
PTFE tubing has superb electrical properties, indicated by a low dielectric constant of 2.1 between -40 °F and 480 °F within a frequency range of 5 Hz to 10 GHz.

PTFE tubing is also an excellent insulator with surface resistivity of 3.6 X 1012 ohms (even at 100% relative humidity).

Short time dielectric strengths range from 500 volts/mil (1 mil = 10-3 in) for thicknesses greater than 100 mils to 4000 volts/mil for very thin films.

FEP Properties:

Electrical FEP exhibits most of the properties of PTFE. However, because of its excellent electrical FEP properties, FEP tubing is a valuable and versatile electrical insulator.

Chemical FEP tubing is inert to most chemicals and solvents, similar to PTFE

Weathering FEP tubing products are virtually unaffected by weather elements. Its resistance to extreme heat, cold, and UV radiation further suits FEP properties for electronic applications.

ETFE Properties

ETFE is distinguished from perfluopolymers (totally fluorinated polymers) as a partially fluorinated copolymer of ethylene and TFE. This chemical modification provides significantly higher strength relative to PTFE, FEP or PFA. It is less flexible than PTFE, but has superior impact strength, abrasion and cut through resistance. Addition of a third component to the chemical structure creates a modified ETFE that has lower weight per unit volume, is stiffer and tougher than PTFE, PFA or FEP. These properties allow it to withstand greater physical abuse during its lifetime. For example, glass reinforced ETFE has outstanding wear characteristics and may be used for bearing applications. ETFE is also suitable for pump impellers or moving parts of equipment that are operating in chemically aggressive environments (check to ensure chemical compatibility).

PVDF Properties

PVDF (KYNAR®) is generally used in applications requiring the high purity, strength, and resistance to solvents, acids, bases and heat. Compared to other fluoropolymers, like PTFE, PFA, FEP, it has an easier melt process because of its relatively low melting point of around 177°C.

PCTFE Properties

PCTFE or CTFE (originally known as Kel-F*) has many of the properties similar to other fluoropolymers such as PTFE, FEP or PFA, but is mechanically superior in rigidity (does not deform easily), and has very low gas permeability . Its dimensional stability makes it attractive for use as a component of a structural part where the high temperature and chemical resistance of fluoropolymers is required. PCTFE shows high compressive strength and low deformation under load. However, its relative cost is one of the major considerations in its selection, since it is quite expensive.

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