Page 340 - Engineering Plastics Handbook

298 Engineering Plastics

TABLE 13.3 Physical and Thermal Properties of Polysulfone (PSF), Polyethersulfone
(PES), and Polyphenylsulfone (PPSF)
ASTM
Property test method PSF PES PPSF
Color Light yellow Light amber Light amber
Clarity Transparent Transparent Transparent
a
Haze, % D-1004 <7 <7 <7
b
Light transmittance, % 80 70 70
Refractive index D-1505 1.63 1.65 1.67
3
Density, g/cm D-1505 1.24 1.37 1.29
Glass transition 185 220 220
c
temperature, °C
Heat deflection D-648 174 204 207
d
temperature, °C
Continuous-service 160 180 180
e
temperature, °C
Coefficient of linear D-696 5.1 × 10 −5 5.5 × 10 −5 5.5 × 10 −5
thermal expansion
Specific heat at 23°C, J/(g⋅K) 1.00 1.12 1.17
Thermal conductivity, W/(m⋅K) C-177 0.26 0.18 0.35
Water absorption, %
In 24 h D-570 0.22 0.61 0.37
At equilibrium D-570 0.62 2.1 1.1
Mold shrinkage, cm/cm D-955 0.005 0.006 0.006
Temperature at 10%
f
TGA wt. loss
In nitrogen 512 547 550
In air 507 515 541
a
As measured on 3.1-mm-thick specimens.
b
Typical values—varies with color.
c
Onset value as measured by differential scanning calorimetry.
d
As measured on 3.1-mm-thick ASTM specimens under a load of 1.82 MPa.
e
Practical maximum long-term use temperatures for PSF and PES based on UL-746
thermal rating data; value for PPSF is an estimate.
f
Thermogravimetric analysis run at heating rate of 10°C/min and 20 mL/min gas (nitrogen
or air) flow rate.
deal of progress has been made over the years toward minimizing the
yellowness of the resins. As a result, the appearance of PSF is fast
approaching the water-white character of polycarbonate. Another fea-
ture of the sulfone polymers is their high refractive index, which derives
from the highly aromatic nature of the backbone. The refractive indices
are substantially higher than those of other amorphous materials made
from olefinic or other aliphatic backbones. The refractive indices of PSF,
PES, and PPSF increase in the order PSF < PES < PPSF, following the
order of increasing aromaticity in the polymer backbone. The high
refractive index feature is of interest to some optical and optoelectronic
lens applications as it allows higher light-bending power for a given
lens curvature or thickness.
The amorphous character of polysulfones also contributes to minimal
and isotropic shrinkages upon cooling during and after melt fabrication.