FKM (Fluoroelastomer / Viton) vs PET (Polyester): 0% composition overlap. Significantly different materials serving different application areas.
FKM (Fluoroelastomer / Viton) vs PET (Polyester)
Side-by-side chemical composition and mechanical property comparison.
Overview
FKM (Fluoroelastomer / Viton)
Fluoroelastomer — THE high-temperature and chemical-resistant rubber. Outstanding resistance to oils, fuels, acids, and solvents at temperatures up to 200°C (short-term 230°C). Fluorine content (64-70%) determines chemical resistance. Trade names: Viton (Chemours), Tecnoflon (Solvay), Dai-El (Daikin). 5-10x more expensive than NBR. Used for aerospace fuel seals, chemical process seals, automotive fuel injector O-rings, semiconductor processing, and any seal exposed to aggressive chemicals at high temperature.
PET (Polyester)
Polyethylene Terephthalate (semi-crystalline stock shape) — combines the stiffness of POM with the wear resistance of PA, without centerline porosity or moisture sensitivity. Excellent dimensional stability, low friction, very low water absorption (~0.1%). Better creep resistance than POM or PA. Widely known from bottles/packaging, but engineering PET-P is semi-crystalline and much stiffer. Trade names include Ertalyte (MCAM), Arnite (DSM), Rynite (DuPont, GF grades). Used for precision bearings in water, gears, slide elements, pump parts, and electrical insulators.
| FKM (Fluoroelastomer / Viton) | PET (Polyester) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | ISO 37 | ISO 10350 |
Chemical composition (wt%) — Pro
| Element | FKM (Fluoroelastomer / Viton) | PET (Polyester) | Overlap |
|---|---|---|---|
| Vinylidene Fluoride (VDF) | 30–60% | — | — |
| Hexafluoropropylene (HFP) | 25–45% | — | — |
| Tetrafluoroethylene (TFE) | 0–30% | — | — |
| Base Polymer (Polyethylene Terephthalate) | — | 99–99.9% | — |
Mechanical properties — Pro
| Property | FKM (Fluoroelastomer / Viton) | PET (Polyester) | Unit |
|---|---|---|---|
| Tensile Strength | 8–17 | 55–80 | MPa |
| Elongation | 150–350 | 30–80 | % |
| hardness_shore_a | 60–90 | — | Shore A |
| Density | |||
| continuous_service_temp | |||
| Yield Strength | |||
| Elastic Modulus | |||
| Glass Transition Temp (Tg) | |||
| Melting Point | |||
| Water Absorption (24h) |
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Sign up free — 3 comparisons/day freeCompatibility Assessment
FKM (Fluoroelastomer / Viton) and PET (Polyester) have significantly different compositions (0% overlap). These materials are not interchangeable and serve different application areas.
Automated assessment based on composition analysis
Frequently Asked Questions
Is FKM (Fluoroelastomer / Viton) the same as PET (Polyester)?
FKM (Fluoroelastomer / Viton) and PET (Polyester) have a 0% composition overlap. They are generally not directly interchangeable.
Can I replace FKM (Fluoroelastomer / Viton) with PET (Polyester)?
Generally not recommended. The compositions differ significantly (0% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between FKM (Fluoroelastomer / Viton) and PET (Polyester)?
The main differences are in the following elements: overall alloying content. FKM (Fluoroelastomer / Viton) is a Polymers grade, while PET (Polyester) is a Polymers grade.
Related Comparisons
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Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.