Even though PTFE remains a niche polymer among more generic materials such as PP (Polypropylene), PVC, PE (Polyethylenes, such as HDPE and LDPE), and even Nylons, within the engineering space it is now quite common. Most applications involving high temperature, corrosive chemicals, high voltages, or high wear/friction now look to PTFE automatically as a solution.
Despite this, there do exist applications where PTFE does not fit the bill and a compromise must be made. For example, applications where high dimensional stability is needed across a wide temperature range, PTFE tends to fall short. The high linear thermal expansion coefficient of PTFE means that it cannot hold its dimensions as temperatures vary. In our own experience, a PTFE can exhibit linear dimensional changes of up to 3% when the temperature moves from 0 to 100 Deg C.
In such a situation, we have seen PEEK being adopted. While PEEK does do the trick, it is also 10X the cost of PTFE. Similarly, certain applications where cost is a constraint need to make do with POM (Delrin), or even PVC, where PTFE cannot be used. In such a scenario, we possibly forego some of PTFE’s key properties.
Over the years a variety of new polymers have been developed to fill the performance and commercial gaps between PEEK and PTFE. These include PFA, FEP, PEK, PPS (Ryton), and PCTFE.
What is PCTFE?
Although not well known, PCTFE (Polychlorotrifluoroethylene) forms an ideal substitute for PTFE in certain applications where PTFE is unable to perform adequately. The table below is meant to offer a snapshot comparison of the two, such that any application engineer can evaluate the key differences.


Unit 
PTFE 
PCTFE 
Remarks 
Properties 
Tensile Strength 
Mpa 
2030 
3035 
With a marginally higher tensile strength, PCTFE rates higher than PTFE on this metric 
Elongation 
% 
200350 
100250 
PCTFE is stiffer than PTFE, which means it lacks some of the softness of PTFE when it comes to sealing, but that it also holds its dimensions more easily 

Melting Point 
Deg. C 
350380 
200220 
PTFE is still preferred on outright hightemperature applications 

Dielectric Breakdown Voltage 
KV/mm 
50100 
2040 
PTFE rates higher on outright dielectric strength 

Coefficient of Friction 

0.030.05 
0.250.35 
PTFE rates higher as a nonstick material 







Processing 
Injection Moulding 

No 
Yes 
PCTFE has more versatility when processing, allowing for more complex parts 
Compression Moulding 

Yes 
Yes 







Characteristics 
Chemical Resistance 

Extreme 
Very Good 
PTFE is still unmatched in chemical resistance 
Thermal Stability 

OK 
Very Good 
PCTFE rates higher than PTFE when it is a question of stability over a wide range of temperatures 

Price 
Med 
High 
PCTFE is more expensive than PTFE, and is therefore used in specific applications only 
As you can see from the above chart, PCTFE and PTFE each have unique advantages and disadvantages when compared with one another. Like all polymers, the application needs to be properly understood and the commercials need to be weighed in before any decision can be made.
In recent times, the enquiries for PCTFE  both as a rod and as a finished component  has increased significantly. With more cryogenic applications (fuelled in no small way by the boom in the medical industry due to COVID), PCTFE is being recognised more and more as an invaluable material for low temperature use.
While the PTFE vs PCTFE debate will always have two sides, it is fair to say that when dimensional stability across a temperature range is a must, PCTFE is growing to become a most effective substitute to PTFE.
Datasheet for PCTFE:
Property 
Value 
Units 
Method 
MECHANICAL PROPERTIES 

Tensile Strength 
4860  5710 
psi 
D 638 
Elongation 
100  250 
% 
D 638 
Flexural Strength, 73°F 
9570  10300 
psi 

Flex Modulus 
200 – 243 x 103 
psi 

Impact Strength, Izod, 23 deg C 
2.5 – 3.5 
ftlb/in 
D 256 
Compressive Stress at 1% deformation, 
1570 – 1860 
psi 
D 695 
Density 
2.10 to 2.17 
gm/cu.cm 

THERMAL PROPERTIES 

Coefficient of Linear Expansion 
7 x 105 
K1 

Melting Point 
410 414 
deg F 

Thermal Conductivity 
1.45 
Btu·in/h·ft2·°F 
ASTM C 177 
Specific Heat 
0.22 
Btu/lb/deg F 

Heat Distortion Temperature, 66 lb/sq.in (0.455 MPa) 
259 
deg F 
D 648 
Processing Temperature 
620 
deg F 

ELECTRICAL PROPERTIES 

Dielectric Strength, short time, 0.004” 
3000 
Volt/mil 
D 149 
ArcResistance 
360 
sec 
D 495 
Volume Resistivity, @ 50% RH 
2 x 1017 
ohmcm 
D 257 
Surface Resistivity, @ 100% RH 
1 x 1015 
Ohm sq1 
D 257 
Dielectric Constant, 1 kHz 
2.6 
ε 
D15081 
Dissipation Factor, @ 1 kHz 
0.02 
D15081 

OTHER PROPERTIES 

Water Absorption 
0.00 
% increase in weight 
D57081 
Flame Rating+ 
Nonflammable 
D 635 

Coefficient of friction (Dynamic) 
0.250.35 
D 1894 

Specific Gravity 
2.10 to 2.17 
D792 

Moisture Permeability Constant 
0.2 
g/m, 24 hours 

O2 Permeability 
1.5 x 1010 
Cc, cm/sq.cm, sec, atm 

N2 Permeability 
0.18 x 1010 
Cc, cm/sq.cm, sec, atm 

CO2 Permeability 
2.9 x 1010 
Cc, cm/sq.cm, sec, atm 

H2 Permeability 
56.4 x 1010 
Cc, cm/sq.cm, sec, atm 