Modified PTFE - Optimization through Modification
Modified PTFE is distinguished from conventional PTFE by the incorporation of perfluorinated modifiers (e.g., perfluoropropyl vinyl ether) in the polymer chain.
To improve the melting behavior and thus the product properties of PTFE, modified PTFE has significantly shorter molecule chains.
Shorter polymer chains tend strongly toward crystallization when cooled from the melt and would therefore negatively impact the mechanical properties without the use of modifiers.
The modifiers suppress crystallization to such an extent that the positive properties of the improved melting behavior can be combined with the good mechanical properties of standard PTFE.
While the typical advantages of PTFE are retained, modified PTFE also exhibits the following positive properties:
- Reduction of cold flow by a factor of three because of the increased number of (smaller) crystallites in the PTFE
- Increased transparency
- Decreased porosity and smoother surfaces
- Reduced gas permeation
- Reduced pore formation when stretched (stretch void index)