AODD Pump Diaphragm Materials: PTFE vs Santoprene vs Neoprene vs Viton vs EPDM
Table of Contents
The diaphragm is the highest-wear component in any AODD pump — and its material decides which fluids the pump can safely handle. This guide compares the five common diaphragm materials so you can match the right one to your media.
Why Diaphragm Material Matters
The diaphragm flexes millions of times, contacts the pumped fluid directly, and separates the air side from the fluid side. Choose the wrong material and the diaphragm can swell, crack, dissolve or lose flexibility — leading to leaks, stalling and unplanned downtime. Choose right and it runs for years.
PTFE — The Chemical Champion
Best for: aggressive chemicals, strong acids, solvents, plating solutions.
- Excellent chemical resistance — nearly the full pH range
- Temperature range: -60°C to +260°C
- Low friction — good for sticky or crystallizing media
- Less elastic than elastomers — typically overmolded or backed by a secondary elastomer for flexibility
PTFE diaphragms are the default for chemical transfer and dosing applications. Pairs with PTFE-bodied pumps.
Santoprene — The General-Duty Workhorse
Best for: general industrial, water, wastewater, mild acids and alkalis.
- Thermoplastic vulcanizate (TPV) with good elasticity and fatigue life
- Temperature range: -40°C to +135°C
- Good abrasion resistance
- Cost-effective and widely available
If you only stock one diaphragm material, make it Santoprene — it covers most general-duty and wastewater jobs.
Neoprene — Oils & General Duty
Best for: oils, mild chemicals, general industrial transfer.
- Good resistance to oils and greases
- Temperature range: -20°C to +100°C
- Good physical strength and flex life
A classic choice for oil transfer and plant maintenance duty.
Viton/FKM — Fuels & High Temperature
Best for: fuels, lubricants, aromatics, high-temperature media.
- Excellent resistance to fuels, oils, solvents and aromatic hydrocarbons
- Temperature range: -20°C to +200°C
- Premium price — justified where compatibility demands it
Choose Viton when pumping diesel, gasoline, aromatics or hot process fluids.
EPDM — Water & Food
Best for: water, steam, food & beverage, brewing, mild acids.
- Excellent resistance to water, steam, ozone and weathering
- Temperature range: -40°C to +150°C
- FDA-grade EPDM available for food contact
- Not compatible with petroleum products — never use with oils or fuels
EPDM is the standard for food & beverage and potable water service.
Material Selection Table
| Material | Chemical Resistance | Temp Range | Best For | Avoid |
|---|---|---|---|---|
| PTFE | Excellent | -60~260°C | Acids, solvents, plating | — |
| Santoprene | Good | -40~135°C | General duty, wastewater | Strong solvents |
| Neoprene | Good | -20~100°C | Oils, general transfer | Strong acids, ketones |
| Viton/FKM | Excellent | -20~200°C | Fuels, aromatics, heat | Skydrol/brake fluid |
| EPDM | Excellent | -40~150°C | Water, food, steam | Petroleum products |
Quick rule: strong acids → PTFE · general duty → Santoprene · oils & fuels → Viton · water & food → EPDM.
How to Check What You Have
Find the part number printed on your old diaphragm or the pump nameplate, then match it in our diaphragm reference table. If the marking is worn, send us a photo — we identify the material and part number for free. Confirming before you order prevents the wrong-part delay.
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Written by
Ray ChanCCTV Buyer's Guide Author · Full-Color Night Vision Specialist. Ray helps global importers and integrators source factory-direct security cameras.