PEEK, unlike PTFE, is a much harder more ridged material.
It does however have a few similarities in that it has a very high working temperature, 250 deg C continuous and up to 300 deg C for short term use, it has a very good chemical resistance, almost as good as PTFE, making it an ideal material for applications where it can replace metal parts or the amount of pressure is raised to the point where PTFE would start to fail.
In its virgin state PEEK has limited frictional properties, but this can be overcome as a compound with the addition of fillers such as Carbon, Graphite and PTFE giving it much better tribological properties ideal for bearings and slide ways.
Another compound that is commonly used is Glass fibre filled PEEK which increases the wear resistance and strength to give it an even greater ability to withstand high pressures.
The addition of fillers as with most plastics also improve the creep resistance of the material.
Below is a chart showing some generic mechanical properties of PEEK and a few of its compounds.
|
Material |
Tensile strength At yield |
Elongation At break |
Compressive strength |
Charpy impact |
Hardness Shore D |
|
Virgin PEEK |
98 MPa |
45 % |
125 MPa |
7 kJ m-2 |
85 |
|
30% Glass filled PEEK |
185 MPa |
2.8 % |
250 MPa |
8 kJ m-2 |
88 |
|
30% Carbon filled |
265 MPa |
1.7 % |
320 MPa |
7 kJ m-2 |
88 |
|
Car/ Gra/PTFE filled PEEK |
150 MPa |
2.3 % |
170 MPa |
5 kJ m-2 |
83 |
|
20% PTFE filled PEEK |
78 MPa |
25 % |
105 MPa |
6 Kj M-2 |
81 |
