Mar 5 2003
Polyetherimide ( PEI ) is an amorphous, transparent and amber high performance thermoplastic with the characteristics common to this group - see polyetheretherketone ( PEEK ).
Relative to PEEK it is less temperature resistant, less expensive and lower in impact strength. Polyetherimide ( PEI ) is prone to stress cracking in chlorinated solvents.
Applications
Applications of Polyetherimide ( PEI ) include electrical switchgear, connectors and other components, microwaveable cookware and “under-bonnet” components.
Key Properties
The key properties of Polyetherimide ( PEI ) are tabulated below.
Table 1. Key properties
| Chemical Resistance |
| Acids - dilute |
Good |
| Alkalis |
Good/Fair |
| Aromatic hydrocarbons |
Good |
| Electrical Properties |
| Dielectric constant @ 1 kHz |
3.1 |
| Dielectric strength ( kV.mm-1 ) |
30 @ 1.6 mm |
| Dissipation factor @ 1 MHz |
0.0013 @ 1 KHz |
| Surface resistivity ( ohm/sq ) |
4.1013 |
| Volume resistivity ( ohm.cm ) |
7.1015 |
| Mechanical Properties |
Abrasive resistance - ASTM D1044
( mg/1000 cycles ) |
10 |
| Compressive modulus ( GPa ) |
2.9 |
| Compressive strength ( MPa ) |
140 |
| Elongation at break ( % ) |
60 |
| Hardness - Rockwell |
R125 |
| Izod impact strength ( J.m-1 ) |
50 |
| Poisson’s ratio |
0.44 |
| Tensile modulus ( GPa ) |
2.9 |
| Tensile strength ( MPa ) |
85 |
| Physical Properties |
| Density ( g.cm-3 ) |
1.27 |
| Flammability |
V-0 @ 0.4 mm |
| Limiting oxygen index ( % ) |
47 |
| Resistance to Ultra-violet |
Good |
| Water absorption - equilibrium ( % ) |
1.3 |
| Water absorption - over 24 hours ( % ) |
0.25 |
| Thermal Properties |
| Coefficient of thermal expansion ( x10-6 K-1 ) |
56 |
| Heat-deflection temperature - 0.45 MPa (°C ) |
200 |
| Heat-deflection temperature - 1.8 MPa (°C ) |
190 |
| Specific heat ( kJ.kg-1.K-1 ) |
2.0 |
| Thermal conductivity @ 23 °C ( W.m-1.K-1 ) |
0.22 |
| Upper working temperature (°C ) |
170-200 |
| Properties Polyetherimide Film |
| Property |
|
Value |
| Dielectric Strength @ 25 µm thick |
KV.mm-1 |
254 |
| Dissipation Factor @ 1 MHz |
|
0.0023 @ 1 KHz |
| Elongation at Break |
% |
15 |
| Permeability to Oxygen @ 25 °C |
x10-13.cm3.cm.cm-2.s-1.Pa-1 |
0.01 |
| Permeability to Water @ 25 °C |
x10-13.cm3.cm.cm-2.s-1.Pa-1 |
1 |
| Tensile modulus - Longitudinal |
GPa |
2.5 |
| Tensile modulus - Transverse |
GPa |
2.5 |
| Tensile strength - Longitudinal |
MPa |
85 |
| Tensile strength - Transverse |
MPa |
85 |
| Volume Resistivity |
Ohm.cm |
5.1015 |
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