FR-4 (Glass Epoxy Laminate) vs PEI (Ultem): 0% composition overlap. Significantly different materials serving different application areas.
FR-4 (Glass Epoxy Laminate) vs PEI (Ultem)
Side-by-side chemical composition and mechanical property comparison.
Overview
FR-4 (Glass Epoxy Laminate)
Flame retardant woven fiberglass cloth with epoxy resin binder — the worldwide standard substrate material for printed circuit boards (PCBs). Designated NEMA grade FR-4 and IPC-4101. Good mechanical strength, dimensional stability and electrical insulation up to 130°C (Tg). Dielectric constant 4.2–4.7 at 1 MHz. Self-extinguishing (UL94 V-0). Used for single/multilayer PCBs, electrical insulation boards, structural composites in electronics, test fixtures and jigs. Available in thicknesses 0.1–50 mm.
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.
| FR-4 (Glass Epoxy Laminate) | PEI (Ultem) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | IPC-4101 | ISO 10350 |
Mechanical properties
| Property | FR-4 (Glass Epoxy Laminate) | PEI (Ultem) | Unit |
|---|---|---|---|
| Flexural Strength | 380–480 | — | MPa |
| Tensile Strength | 280–340 | — | MPa |
| Compressive Strength | 350–420 | — | MPa |
Compatibility Assessment
FR-4 (Glass Epoxy Laminate) 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 FR-4 (Glass Epoxy Laminate) the same as PEI (Ultem)?
FR-4 (Glass Epoxy Laminate) and PEI (Ultem) have a 0% composition overlap. They are generally not directly interchangeable.
Can I replace FR-4 (Glass Epoxy Laminate) 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 FR-4 (Glass Epoxy Laminate) and PEI (Ultem)?
The main differences are in the following elements: overall alloying content. FR-4 (Glass Epoxy Laminate) 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.
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