PEI (POLYETHER-IMIDE)
ULTEM®

SPECIFICATIONS:
   NONE

NATURAL COLOUR:
   DARK AMBER (TRANSLUCENT in THIN SECTIONS)

Another of the high performance, high temperature resistant polymers, possessing very good physical and electrical insulation properties, PEI, like many of the other SPECIALTIES has applications in such high-tech areas as aerospace, aircraft, medical and electronics. As well, PEI has good chemical resistance, for an amorphous polymer, and has excellent flame resistance with low smoke generation when exposed to flames. Due to the ease of processing, the cost of the enhanced benefits of PEI over other engineering polymers such as Nylons, PET and Acetals is not as dramatic as with many of the other SPECIALTIES. PEI retains much of its high modulii at higher temperatures while maintaining stable electrical insulation characteristics over wide thermal and frequency ranges. In addition, PEI can be repeatedly autoclaved without degradation. And PEI has very good resistance to gamma and UV radiation. PEI is attacked by common organic solvents thus water or water-soluble oils can only be used for machining. With high stiffness, hardness, temperature resistance and low coefficient of thermal expansion, PEI has very good machinability. High speed tooling run at high speeds and high feeds produces very good finish and high tolerance parts. Carbide should be used with glass filled grades. PEI suffers from poor notch impact resistance and this must be considered and compensated for in any part design. With its susceptibility to organic solvents, PEI responds well to solvent cementing. As with other high temperature resistant polymers, hot gas welding, spin welding and butt-welding procedures can be successful if sufficient heat can be put into the weld area.

GENERAL PROPERTIES
  ASTM
test
Natural 20% Glass
Filled
30% Glass
Filled
SPECIFIC GRAVITY   D792 1.27 1.42 1.51
TENSILE STRENGTH psi D638 15200 20100 24500
TENSILE MODULUS 105 psi D638 4.3 10.0 13.0
ELONGATION % D638 60 3 3
FLEXURAL STRENGTH psi D790 22000 30000 33000
FLEXURAL MODULUS 105 psi D790 4.8 9.0 13.0
COMPRESSIVE STRENGTH 10% psi D695 21900 28700 30700
COMPRESSIVE MODULUS 105 psi D695 4.80 8.09 9.38
HARDNESS rockwell M D785 M109 M114  
  rockwell R D785     R114
IMPACT STRENGTH (1/2" x 1/2") ft-lb/inch of notch D256 1.0 1.6 2.0
THERMAL EXPANSION 10-5/°F D696 3.1 1.8 1.1
HEAT RESISTANCE (continuous in air) °F   338 338 356
DEFLECTION TEMPERATURE   D648      
@ 264 psi °F   392 408 410
@ 66 psi °F   410 410 414
DIELECTRIC STRENGTH v/mil D149      
DIELECTRIC CONSTANT   D150 3.1 3.5 3.7
DISSIPATION FACTOR 10-3 D150 1.3 to 2.5 1.5 to 4.9 1.5 to 5.3
WATER ABSORPTION 24hrs % D570 0.25 0.19 0.16
FLAMMABILITY in/min D635 <0.02 <0.02 <0.02

PLEASE NOTE:
Values shown in the above table are averages and there will be variances from lot to lot. After selecting a material based upon these values, you must conduct tests specific to your application to be assured the material suits your needs.