GFRP / GFK (Glass Fiber Reinforced Epoxy) vs PEI (Ultem): 0% composition overlap. Significantly different materials serving different application areas.
GFRP / GFK (Glass Fiber Reinforced Epoxy) vs PEI (Ultem)
Side-by-side chemical composition and mechanical property comparison.
Overview
GFRP / GFK (Glass Fiber Reinforced Epoxy)
Glass fiber reinforced epoxy composite — the cost-effective structural composite for industrial, marine and construction applications. E-glass fiber in epoxy matrix. Unidirectional: UTS ~1000 MPa, E ~40 GPa. Quasi-isotropic layup: UTS ~300 MPa, E ~18 GPa. Density 1.8–2.1 g/cm³. Electrically insulating (unlike CFRP). Used for boat hulls, wind turbine blades, chemical tanks/pipes, architectural panels, ladders, gratings, automotive body panels and electrical insulation structures.
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.
| GFRP / GFK (Glass Fiber Reinforced Epoxy) | PEI (Ultem) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | ASTM D3039 | ISO 10350 |
Chemical composition (wt%) — Pro
| Element | GFRP / GFK (Glass Fiber Reinforced Epoxy) | PEI (Ultem) | Overlap |
|---|---|---|---|
| Epoxy Resin Matrix | 30–45% | — | — |
| Glass Fiber Reinforcement | 55–70% | — | — |
| Base Polymer (Polyetherimide) | — | 99–99.9% | — |
Mechanical properties — Pro
| Property | GFRP / GFK (Glass Fiber Reinforced Epoxy) | PEI (Ultem) | Unit |
|---|---|---|---|
| Tensile Strength | 900–1100 | — | MPa |
| Tensile Modulus | 38–45 | — | GPa |
| Density | 1.8–2.1 | — | g/cm³ |
| Fiber Volume Fraction | |||
| Glass Transition Temp (Tg) | |||
| Water Absorption (24h) | |||
| Tensile Strength | |||
| Yield Strength | |||
| Elongation | |||
| Elastic Modulus | |||
| Density | |||
| Glass Transition Temp (Tg) | |||
| Continuous Use Temp | |||
| Water Absorption (24h) |
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GFRP / GFK (Glass Fiber Reinforced Epoxy) 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 GFRP / GFK (Glass Fiber Reinforced Epoxy) the same as PEI (Ultem)?
GFRP / GFK (Glass Fiber Reinforced Epoxy) and PEI (Ultem) have a 0% composition overlap. They are generally not directly interchangeable.
Can I replace GFRP / GFK (Glass Fiber Reinforced Epoxy) 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 GFRP / GFK (Glass Fiber Reinforced Epoxy) and PEI (Ultem)?
The main differences are in the following elements: overall alloying content. GFRP / GFK (Glass Fiber Reinforced Epoxy) is a Polymers grade, while PEI (Ultem) 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.