Page 347 - Engineering Plastics Handbook

304 Engineering Plastics

TABLE 13.6 Flammability and Burning Behavior of Polysulfone, Polyethersulfone,
and Polyphenylsulfone
Property Test method PSF PES PPSF

Flammability rating UL-94 V-0 at 6.1 mm V-0 at 0.8 mm V-0 at 0.8 mm
Limiting oxygen index ASTM D-286 30.0 38.0 38.0
Smoke density * ASTM E-662 90 at 1.5 mm 35 at 6.2 mm 30 at 6.2 mm †
Self-ignition ASTM D-1929 621 502 —
temperature, °C
*
Specific optical density D m at flaming condition.
†
Thickness.

Electrical properties
Polysulfones exhibit excellent dielectric properties. They exhibit high
dielectric breakdown strength and low dielectric constant. They also
exhibit low dielectric loss. Because they are amorphous, the electrical
properties such as dielectric constant and dissipation factor are stable
across a wide temperature range. They are also stable over a wide fre-
quency range. The desirable electrical properties in concert with
attractive flammability properties have made polysulfones successful
in many electrical and electronic insulation, business machine, and
lighting applications. Polysulfone electrical properties can be found
in Table 13.7.

Resistance to chemical environments
In general, amorphous plastics are susceptible to cracking by particu-
lar chemical environments when under stress. This behavior is called

TABLE 13.7 Electrical Properties of Polysulfone, Polyethersulfone,
and Polyphenylsulfone
Property ASTM test method PSF PES PPSF

Dielectric strength, D-149 16.6 15.5 14.6
*
3.2 mm, kV/mm
Volume resistivity, Ω⋅cm D-257 7 × 10 16 9 × 10 16 9 × 10 15
Dielectric constant at D-150
60 Hz 3.18 3.65 3.44
3
10 Hz 3.17 3.65 3.45
6
10 Hz 3.19 3.52 3.45
Dissipation factor at D-150
60 Hz 0.0008 0.0019 0.0006
3
10 Hz 0.0008 0.0023 —
6
10 Hz 0.0051 0.0048 0.0076
*
Thickness.