Views: 0 Author: Rio Liang Publish Time: 2026-09-14 Origin: Site
PEEK (polyetheretherketone) and PTFE (polytetrafluoroethylene, sold as Teflon) are two different plastics that overlap on temperature and chemistry but solve opposite problems. Both serve continuously at 260°C and both shrug off most chemicals — yet PTFE is the slipperiest solid polymer known, at 25–35 MPa tensile strength, while PEEK is the strongest machinable plastic at high temperature, at 100 MPa. PTFE is the right choice when the part slides, seals or lines something and carries no structural load. PEEK is the right choice when the part carries load, wears, or must hold tolerance at temperature. And when you need low friction and load capacity in one part, the answer is PTFE-filled PEEK — the bearing grade covered at the end.
We machine and supply both materials in-house, so this comparison quotes the differences that decide real projects rather than the ones that look good on a datasheet.
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Pick PTFE when the part slides, seals or lines something and carries little or no structural load — maximum chemical inertness and minimum friction at the lowest cost.
Pick PEEK when the part carries load, wears, or must hold tolerance at temperature — 4× the strength, far higher stiffness, and creep resistance PTFE cannot approach.
Same 260°C, different reality: PTFE survives 260°C only unloaded — under load it cold-flows well below 100°C. PEEK carries structure at 250°C+. Temperature alone never decides this comparison; load does.
| Property | PEEK (unfilled) | PTFE (typical) |
|---|---|---|
| Tensile strength | 100 MPa | 25–35 MPa |
| Flexural modulus | 4.1 GPa | ~0.6 GPa |
| Hardness (indicative) | ~Shore D 84–86 | ~Shore D 55–60 |
| Friction coefficient (dry) | ~0.25–0.35 | 0.05–0.10 |
| Wear resistance | Excellent | Poor under load |
| Continuous service (unloaded) | 260°C (300°C short-term) | 260°C |
| Load-bearing ceiling (typical) | 260°C+ | ~100°C |
| Melting point | 343°C | ~327°C |
| Chemical resistance | Excellent (a few strong oxidizers attack) | Essentially universal |
| Relative cost | $$$$$ | $$ |
PEEK values are PRES stock-grade data. PTFE figures are industry typical values for virgin unfilled resin — the producer's TDS governs. Friction coefficients vary strongly with counterface, speed and load; the load-bearing ceiling is an application-typical figure, not a datasheet rating.
On paper the temperature ranges tie: both plastics are rated for continuous service at 260°C. In practice the rating means different things. PTFE reaches 260°C only when the part is unloaded — its useful mechanical ceiling sits around 100°C, because cold flow accelerates as temperature rises and a loaded PTFE part simply keeps deforming. PEEK carries structure to 250°C and beyond: unfilled grades hold roughly 30 MPa of tensile strength at 200°C, and glass- or carbon-filled grades hold far more.
The two extremes differ as well. PTFE wins the deep cold — it stays usable down to around −200°C, which is why it lines cryogenic equipment. PEEK also runs at cryogenic temperatures (liquid-nitrogen duty is common) but its best argument is the hot side: glass transition at 143°C, melting point 343°C, HDT from 152°C unfilled to 315–336°C in glass- and carbon-filled grades. For a full walkthrough of PEEK's thermal numbers on its own, see our PEEK thermal properties guide.
The numbers above are the whole story in miniature. Unfilled PEEK carries 100 MPa in tension with a 4.1 GPa flexural modulus — roughly four times PTFE's strength and seven times its stiffness, with a hardness gap to match. More important is what happens over months: PTFE is the textbook example of cold flow (creep at room temperature). Leave a PTFE washer under a bolt and the preload relaxes; run a PTFE bearing under real load and the clearance closes. PEEK is the opposite — it is specified precisely because a machined part still holds its dimensions and preload after years at 200°C. That single property is why PEEK dominates aerospace brackets, pump wear rings and bearing cages while PTFE sticks to seals and linings.
Fillers widen the gap further: glass-filled PEEK reaches 175 MPa tensile and 11 GPa flexural modulus, and carbon-filled grades 260 MPa and 23 GPa — the data set is on our PEEK material page.
With a dry friction coefficient of 0.05–0.10 (typical), PTFE is the standard against which every "low friction" claim is measured — nothing solid polymer beats it by much. PEEK's unfilled dry friction of ~0.25–0.35 is respectable but not special, and unloaded PTFE also wears slowly. The catch is load: once contact pressure rises, PTFE's wear rate climbs steeply while PEEK's stays low, and PEEK's wear behavior improves with the right fillers. That is why lightly loaded, chemistry-driven sliding jobs (valve seats in aggressive media, linings, low-pressure seals) belong to PTFE, while loaded dry-running bearings belong to filled PEEK.
"Is PEEK similar to Teflon?" usually starts from this non-stick reputation. PEEK shares the low-surface-energy family traits to a degree — parts release easily and pick up little residue — but it is not PTFE's equal on either friction or release. Where that surface property, rather than friction, is what your part needs, see our low surface energy PEEK page for what PEEK can and cannot do in PTFE-style duty.
PTFE is the most chemically inert commercial plastic — molten alkali metals and elemental fluorine are about the only things that touch it. PEEK is not far behind: it resists hydrocarbons, solvents, hydraulic fluids, weak acids and bases, and is outstanding in superheated water and steam where many plastics hydrolyze. The honest exceptions for PEEK are concentrated strong oxidizers (nitric acid, sulfuric acid at high concentration) and some halogenated chemistry at elevated temperature. If your medium is on that short list, PTFE decides the material. Otherwise both survive, and the load decides instead.
One practical difference: PEEK can be attacked slowly by strong UV over years unless pigmented or coated, while PTFE is essentially immune to weathering. For seals and rings specifically — where cold flow, not chemistry, usually ends the argument — the analysis is in our PEEK vs PTFE seals and cold flow comparison.
You do not always have to choose. Bearing-grade PEEK fills the PEEK matrix with PTFE, graphite and reinforcing fiber: the PTFE phase migrates to the rubbing surface and builds a low-friction transfer film, while the PEEK-plus-fiber skeleton carries the load. The result runs dry at friction levels far closer to PTFE than to unfilled PEEK, at PV limits virgin PTFE cannot survive, and it keeps PEEK's dimensional stability. How it compares against the carbon-fiber alternative in wear testing is covered in our bearing grade vs CF30 comparison, and we supply it as machinable PEEK rod stock cut to length.
On price: PTFE stock shapes cost a fraction of PEEK, and no filler changes that ordering — see our PEEK price per kg guide for what drives the premium and when it pays back. We also stock the fluoropolymer family itself; PTFE, PFA and PVDF availability is on our PVDF / PTFE / PFA page. Both plastics sit in the same performance tier we rank in our high-temperature plastics coverage.
Q1: What is PTFE and PEEK — and are they the same material?
A: No. PEEK (polyetheretherketone) is a semi-crystalline high-performance structural plastic from the PAEK family. PTFE (polytetrafluoroethylene) is a fully fluorinated polymer, sold by Chemours under the Teflon brand. They share a 260°C continuous rating and broad chemical resistance, but PEEK is a load-bearing engineering plastic while PTFE is a soft, slippery, non-structural one.
Q2: Is PEEK harder than PTFE?
A: Yes — by a wide margin. PEEK runs around Shore D 84–86 against PTFE's Shore D 55–60, with roughly four times the tensile strength and seven times the stiffness. Hardness, creep resistance and wear life all point the same way: PTFE deforms under sustained load, PEEK does not.
Q3: Is PEEK similar to Teflon?
A: Only in reputation. Teflon is simply PTFE's trade name, and PEEK matches it on temperature and chemical resistance — but not on friction (0.25–0.35 vs 0.05–0.10), release, or non-stick behavior. If your application needs the slippery, non-stick surface itself, PTFE — or PTFE-filled PEEK — is the answer; PEEK's own low surface energy capability is covered on our low surface energy PEEK page.
Q4: Is PEEK more expensive than PTFE?
A: Yes — typically 5–10× the resin price. It is worth it whenever the part carries load, wears, or must hold tolerance at temperature: a failed PTFE bearing or an out-of-tolerance part costs more than the material difference. For no-load sliding or lining duty, PTFE is the correct, cheaper answer.
Q5: What is the temperature range of PEEK compared to PTFE?
A: Both are rated for continuous service at 260°C, but the rating hides the real difference. PTFE's 260°C is an unloaded rating — under load it cold-flows well below 100°C. PEEK carries structure to 250°C+ and handles short-term peaks to 300°C. On the cold side PTFE goes lower, staying usable to about −200°C, while PEEK also serves cryogenic duty including liquid nitrogen.
Q6: What temperature is PEEK good for — and how heat resistant is it?
A: Unfilled PEEK serves continuously at 260°C (short-term 300°C), with a glass transition of 143°C and a melting point of 343°C. The working limit for stiffness is the heat deflection temperature: 152°C unfilled, 315°C in GF30 and 336°C in CF30 grades — so filled PEEK holds tight tolerances past 300°C. It is also inherently flame retardant (UL 94 V-0) with low smoke and toxic-gas emission.
Q7: What is the temperature range of PTFE?
A: Roughly −200°C to 260°C for continuous unloaded service, the widest window of any commercial plastic. The catch is load: PTFE's strength at temperature is minimal and creep accelerates quickly, so the practical load-bearing ceiling sits near 100°C. Chemically and thermally it survives where almost nothing else does — mechanically it does not.
Q8: Which has better chemical resistance, PEEK or PTFE?
A: PTFE, narrowly — it is essentially universal, beaten only by molten alkali metals and elemental fluorine. PEEK matches it against most industrial media but is attacked by concentrated strong oxidizers and some halogenated chemistry at elevated temperature. Unless your process includes those, both qualify and mechanical requirements should decide.
Q9: Which insulates electricity better?
A: PTFE is the purer dielectric — dielectric constant near 2.1 and among the lowest dissipation factors of any solid. PEEK's dielectric constant (~3.2–3.4) is higher but far more stable with temperature, frequency and moisture, which is why PEEK wins structural insulator parts in hot or wet service. The material-by-material selection logic is in our electrical insulation plastic guide.
Q10: Can PTFE be used as a bearing?
A: Only at very low loads and speeds — virgin PTFE cold-flows and wears quickly under real contact pressure. For loaded dry bearings, PTFE works as a filler inside bearing-grade PEEK, where it provides the low-friction film while PEEK carries the load.
Q11: Which machines better?
A: PEEK. It cuts with rigid, well-broken chips and holds tight tolerances after annealing. PTFE is gummy, moves in the chuck, and tolerances relax after machining because of cold flow — parts are often sized after a post-machining settle.
PEEK, PTFE-Filled PEEK — or Something Else?
Send us your load, speed and medium — we stock all grades and will tell you when the cheaper one is right.
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