Design Guide - Solvay Plastics

Stress, MPa
Apparent Modulus, GPa
Figure 46: Tensile Creep Rupture of AS-1133 HS
200
150
100
50
0
65°C (149°F)
100°C (212°F)
150°C (303°F)
0.01 0.1 1 10 100 1,000 10,000
Time to Rupture, Hours
Figure 47: Apparent Flex Modulus at 69 MPa
(10 kpsi) at 23°C (73°F)
12
10
8
6
Flexural Creep - 69 MPa (10 kpsi) Stress
4
0.6
0.4
AS-1133 HS
2
33% GR PA 6,6
0.2
A-1240 L
0
0.0
1 10
100 1,000 10,000
Time, Hours
Figure 48: Apparent Flex Modulus at 14 MPa
(2 kpsi) at 83°C (181°F)
25
20
15
10
5
0
1.6
1.4
1.2
1.0
0.8
Stress, kpsi
Apparent Modulus, Mpsi
Flexural Creep
Flexural creep was determined according to ASTM
D2990 using the three-point bending mode with a
50.8 mm (2 in.) span. Test specimens were 127 mm x
12.7 mm x 3.2 mm (5.0 in. x 0.5 in. x 0.125 in.) injection
molded bars placed on test "dry, as molded". The
environment was maintained at 50% relative humidity
and 23°C (73°F). Stress levels were predetermined
from flexural strength versus temperature curves and
chosen to be 25% to 35% of the ultimate strength of
the material at the test temperature.
Creep resistance can be predicted to a large extent
by the relationship of the service temperature to the
material’s glass transition temperature. Typically, creep
resistance is good at service temperatures much lower
than T g , and becomes poorer as service temperature
approaches T g . Therefore, it is not surprising that
Amodel resins have creep resistance superior to many
traditional semi-crystalline thermoplastics. For example,
Amodel A-1000 resin has a glass transition temperature
of 123°C (253°F) as determined by Differential Scanning
Calorimetry (ASTM D3418). The corresponding T g for
PA 6,6 is 65°C (149°F). At all temperatures up to its T g ,
Amodel resins do have superior creep resistance.
Figure 47 compares the apparent flexural modulus
of Amodel AS-1133 HS and A-1240 L resins to a 33%
glass reinforced PA 6,6. While the AS-1133 HS resin
is clearly superior to the glass reinforced PA, even the
mineral filled grade – Amodel A-1240 resin – has an
effectively higher creep modulus after 1000 hours
under load.
Figure 48 compares the apparent flexural modulus
of Amodel ET-1000 resin with that of unreinforced
and impact modified grades of PA 6,6 at 83°C (181°F)
and 14 MPa (2 kpsi).
Apparent Modulus, GPa
3.0
2.5
2.0
1.5
1.0
0.5
Flexural Creep - 14 MPa (2 kpsi) Stress 83°C (181°F)
ET-1000
PA 6,6
High Impact PA 6,6
400
300
200
100
Apparent Modulus, kpsi
0.0
0.1 1 10 100 1,000
Time, Hours
0
Property Data
Amodel ® PPA Design Guide
35