Polyimide
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| Polyimide | |
|---|---|
| Density | 1430 kg/m3 |
| Young's modulus(E) | 3200 MPa |
| Tensile strength(σt) | 75-90 MPa |
| Elongation @ break | 4-8% |
| notch test | 4-8 kJ/m2 |
| Glass temperature | >400°C |
| melting point | - |
| Vicat B | -C |
| heat transfer coefficient (λ) | 0.52 W/m.K |
| linear expansion coefficient (α) | 5.5 10-5 /K |
| Specific heat (c) | 1.15 kJ/kg.K |
| Water absorption (ASTM) | 0.32 |
| Dielectric constant (Dk) at 1MHz | 3.5 |
| Loss tangent (Df) | 0.002 |
| Price | 15-25 €/kg |
| # ↑ Deformation temperature at 10kN needle load | |
| source: A.K. vam der Vegt & L.E. Govaert, Polymeren, | |
| van keten tot kunstof, ISBN 90-407-2388-5 | |
Polyimide (sometimes abbreviated PI) is a polymer of imide monomers. The structure of imide is as shown below.
There are two general types of polyimides One type, so called linear polyimides, are made by combining imides into long chains. Aromatic heterocyclic polyimides are the other usual kind, where R′ and R″ are two carbon atoms of an aromatic ring. Examples of polyimides include VTEC PI, Kapton, P84, Matrimid, Meldin, and Vespel. Polyimides have been in mass production since 1955.
Polyimide is often used in the electronics industry for flexible cables. For example, in a laptop computer, the cable that connects the main logic board to the display (which must flex every time the laptop is opened or closed) is often a polyimide base with copper conductors.
See also: Polyamide
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