PTFE vs PEEK - A Comparison of Properties
Although both PTFE and PEEK are well established within their respective fields, there are frequently questions around which would better suit a given application. OEMs typically have to make a choice based on technical suitability and hence need to be better informed as to how these materials match up against each other.
Below is a short comparison on properties between these two polymers and can be used a guide to aid new product development.
|Price||Moderately expensive||Very expensive||PTFE|
|Tensile Strength||25-35 Mpa||90-100 Mpa||PEEK|
|Compressive Strength||30-40 Mpa||140 Mpa||PEEK|
|Flexural Modulus||495 Mpa||3900 Mpa||PEEK|
|Coefficient of Friction||0.03-0.05||0.35-0.45||PTFE|
|Temperature resistance||Up to 250°C||Up to 250°C||NA|
|Dielectric strength||50-150 Kv/mm||50 Kv/mm||PTFE|
|Chemical resistance||Virtually inert||Affected by Sulphuric acid||PTFE|
|Coefficient of linear thermal expansion||14 x 10-5/K||5 x 10-5/K||PEEK|
In a nutshell, applications requiring strength and low levels of deformation would usually employ PEEK, whereas those requiring resistance to voltage or chemicals utilize PTFE. PTFE also rates highly in that it is self-lubricating. This makes it a preferred choice in high wear applications.
The biggest disadvantage of PEEK remains the price. It is roughly 10 times the price of PTFE and as a result has remained a niche polymer, used only in applications where it is absolutely necessary.