FR-4 (Glass Epoxy Laminate) vs PI (Polyimide): 0% composition overlap. Significantly different materials serving different application areas.
FR-4 (Glass Epoxy Laminate) vs PI (Polyimide)
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.
PI (Polyimide)
Polyimide — THE extreme-temperature polymer. Continuous use 250-300°C (short-term to 400°C+). Outstanding thermal stability, low outgassing, excellent radiation resistance, and self-lubricating. Available as film (Kapton, DuPont), parts (Vespel, DuPont), and moldable resin. Expensive but irreplaceable where no other polymer survives. Used for aerospace bearings/seals, semiconductor processing, flexible circuit boards (Kapton), jet engine components, and space applications.
| FR-4 (Glass Epoxy Laminate) | PI (Polyimide) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | IPC-4101 | ASTM D638 |
Mechanical properties
| Property | FR-4 (Glass Epoxy Laminate) | PI (Polyimide) | Unit |
|---|---|---|---|
| Flexural Strength | 380–480 | — | MPa |
| Tensile Strength | 280–340 | — | MPa |
| Compressive Strength | 350–420 | — | MPa |
Compatibility Assessment
FR-4 (Glass Epoxy Laminate) and PI (Polyimide) 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 PI (Polyimide)?
FR-4 (Glass Epoxy Laminate) and PI (Polyimide) have a 0% composition overlap. They are generally not directly interchangeable.
Can I replace FR-4 (Glass Epoxy Laminate) with PI (Polyimide)?
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 PI (Polyimide)?
The main differences are in the following elements: overall alloying content. FR-4 (Glass Epoxy Laminate) is a Polymers grade, while PI (Polyimide) is a Polymers grade.
View full data for each material:
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.