4 Diaphragm Materials Explained: PTFE vs Santoprene vs EPDM vs Nitrile

Diaphragm Materials Explained is essential knowledge for anyone specifying, maintaining, or replacing diaphragms in AODD pumps. The diaphragm material determines chemical compatibility, pump lifespan, safety, and overall performance. Selecting the wrong material can result in premature failure, swelling, cracking, or complete pump breakdown.

This guide provides Diaphragm Materials Explained for four of the most common materials: PTFE, Santoprene, EPDM, and Nitrile — helping you choose the right diaphragm for your application.

Choosing the correct diaphragm material protects your pump and ensures safe, efficient operation. Incorrect material choice is one of the main causes of premature diaphragm failure.

With Diaphragm Materials Explained, you can quickly determine which material suits:

✔ Chemical fluids
✔ Abrasive slurries
✔ Oils & hydrocarbons
✔ Food & beverage applications
✔ High-temperature or high-pressure environments

For accurate selection, always check chemical compatibility.

View our chemical compatibility guidelines here

The FDA Food-Contact Substances database provides official safety guidance:

Best For: Aggressive chemicals, solvents, corrosive fluids

PTFE is one of the toughest diaphragm materials available. it offers exceptional chemical resistance and is ideal for highly aggressive applications.

Advantages

• Outstanding chemical resistance
• Non-stick surface reduces build-up
• Excellent temperature tolerance
• FDA-compliant options available

Limitations

• Stiffer than elastomers (reduced flex)
• Typically paired with a backing diaphragm
• Higher cost compared to other materials

Common Applications

• Acids & Caustics
• Solvents (ketones, aromatics, alcohols)
• Chemical processing
• Pharmaceutical & hygienic applications

At Aroplus, we keep a large stop of PTFE diaphragms

Contact us to find out more

Best For: General-purpose chemical pumping, durability, hot fluids

Santoprene is a thermoplastic elastomer combining the flexibility of rubber with the durability of plastic. It is the most common “all-rounder” diaphragm material.

Advantages

• Broad chemical compatibility
• Long service life
• Good for abrasive fluids
• Cost-effective

Limitations

• Not suitable for strong solvents
• Limited resistance to certain oils

Common Applications

• Water-based chemicals
• Slurries and abrasive fluids
• Detergents and cleaning chemicals
• Paints & coatings

For Santoprene diaphragms, Contact us at Aroplus

Best For: Water-based fluids, alcohols, food-grade or hygienic fluids

EPDM is known for its resistance to heat, water, and certain alcohols. It is commonly used in hygienic pumping applications.

Advantages

• Excellent water and steam resistance
• Great for food & beverage applications
• Good resistance to mild chemicals
• FDA-compliant options available

Limitations

• Not compatible with oils or hydrocarbons
• Not suitable for strong solvents

Common Applications

• Water treatment
• CIP chemicals
• Alcohol solutions
• Food and beverage processing

For EPDM Diaphragms, Contact us at Aroplus

Best For: Oils, fuels, hydrocarbons, lubricants

Nitrile diaphragms are best suited for petroleum-based fluids, oils, fuels, and greases.

Advantages

• Excellent compatibility with oils
• Good abrasion resistance
• Cost-effective
• Long service life in hydrocarbon applications

Limitations

• Not suitable for aggressive chemicals
• Poor performance with acidic or alkaline fluids

Common Applications

• Diesel, kerosene, petrol
• Oil transfer
• Lubricants & greases
• Light hydrocarbons

For Nitrile Diaphragms, Contact us at Aroplus

Follow this quick process:

1. Identify the fluid type
   is it a solvent? Acid? Oil? Slurry?
2. Check Chemical compatibility
   Use charts + FDA/ISO references
3. Consider operating conditions
   Temperature, viscosity, abrasion.
4. Evaluate regulatory requirements
   Food-grade? ATEX zone?
   Refer to EU ATEX Guidelines
5. Balance lifespan vs cost
   PTFE = premium chemical resistance
   Santoprene = best general-purpose value
   EPDM = hygienic fluids / alcohols
   Nitrile = oils and hydrocarbons

Choosing the correct diaphragm material prevents:

• Premature failure
• Chemical attack
• Downtime
• Unnecessary maintenance costs

For chemical, water-based food or oil-based fluids, Aroplus carried a full range of PTFE, Santoprene, EPDM, and Nitrile diaphragms, along with service kits, pump replacements, and expert support.

If you are unsure of anything and need support

Contact Aroplus