NBR (Nitrile Rubber) vs PEI (Ultem): 0% composition overlap. Significantly different materials serving different application areas.
NBR (Nitrile Rubber) vs PEI (Ultem)
Side-by-side chemical composition and mechanical property comparison.
Overview
NBR (Nitrile Rubber)
Nitrile butadiene rubber (Buna-N) — THE oil and fuel resistant elastomer. ACN content (18-50%) determines the oil resistance vs low-temp flexibility tradeoff. Higher ACN = better oil resistance but stiffer at low temp. The most widely used seal material worldwide. Used for O-rings, fuel hoses, gaskets, hydraulic seals, oil seals, and nitrile gloves. Not suitable for ozone, UV, or polar solvents (ketones, esters). HNBR variant for higher heat resistance.
PEI (Ultem)
Polyetherimide — high-performance amorphous thermoplastic. Similar properties to PEEK at lower cost but lower impact strength and use temp. Transparent amber color. Tg 217°C, inherent flame resistance (UL94 V-0 at 0.4mm), very low smoke. Hydrolytically stable (2000+ autoclave cycles). Trade name Ultem (SABIC). Used for aerospace interior panels, medical sterilizable devices, electrical insulators, semiconductor handling, and 3D-print build plates.
| NBR (Nitrile Rubber) | PEI (Ultem) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | ISO 37 | ISO 10350 |
Chemical composition (wt%) — Pro
| Element | NBR (Nitrile Rubber) | PEI (Ultem) | Overlap |
|---|---|---|---|
| Butadiene | 50–82% | — | — |
| Acrylonitrile (ACN) | 18–50% | — | — |
| Base Polymer (Polyetherimide) | — | 99–99.9% | — |
Mechanical properties — Pro
| Property | NBR (Nitrile Rubber) | PEI (Ultem) | Unit |
|---|---|---|---|
| Tensile Strength | 7–24 | 85–105 | MPa |
| Elongation | 200–600 | 50–60 | % |
| hardness_shore_a | 40–90 | — | Shore A |
| Density | |||
| continuous_service_temp | |||
| Yield Strength | |||
| Elastic Modulus | |||
| Glass Transition Temp (Tg) | |||
| Continuous Use Temp | |||
| Water Absorption (24h) |
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NBR (Nitrile Rubber) and PEI (Ultem) 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 NBR (Nitrile Rubber) the same as PEI (Ultem)?
NBR (Nitrile Rubber) and PEI (Ultem) have a 0% composition overlap. They are generally not directly interchangeable.
Can I replace NBR (Nitrile Rubber) with PEI (Ultem)?
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 NBR (Nitrile Rubber) and PEI (Ultem)?
The main differences are in the following elements: overall alloying content. NBR (Nitrile Rubber) is a Polymers grade, while PEI (Ultem) is a Polymers grade.
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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.