Design Guide - Solvay Plastics

Figure 56: Dimensional Change of 40% Mineral
Filled PPA
Figure 57: Dimensional Comparison of GR PA 6,6
to GR PPA at 100% RH
Dimensional Change, %
0.6
0.5
0.4
0.3
0.2
0.1
0.0
TD @ 100% RH
FD @ 100% RH
TD @ 50% RH
FD @ 50% RH
FD = Flow Direction
TD = Transverse Direction
0 2 4 6 8 10 12 14
Time, Month
Dimensional Change, %
1.2
1.0
0.8
0.6
0.4
0.2
0.0
AS-1133 HS - TD
AS-1133 HS - FD
33% GR PA 6,6 - TD
33% GR PA 6,6 - FD
FD = Flow Direction
TD = Transverse Direction
0 2 4 6 8 10 12 14
Time, Month
Figure 56 shows the same results for Amodel
A-1340 PPA, a 40% mineral filled grade. Not only
is the magnitude of the dimensional change smaller,
but the difference between flow and transverse direction
is almost negligible.
Dimensional Change Compared to PA 6,6
Figure 57 compares the dimensional change due to
moisture absorption of Amodel AS-1133 HS resin
with that of 33% glass reinforced PA 6,6 at 100% RH.
To ensure a valid comparison, both resins were molded
under conditions that promote maximum crystallinity.
In the case of the Amodel resin, a mold temperature
of 135°C (275°F) was used. For the PA 6,6, the mold
temperature was 93°C (200°F). Plaques with a
thickness of 3.2 mm (0.125 in.) were exposed
to 100% RH at room temperature.
Amodel resin absorbs moisture much more slowly
than PA 6,6, because the diffusion coefficient at room
temperature of water in PA 6,6 is approximately five
times larger than that of Amodel resins. Therefore,
for these plaques, PA 6,6 reaches equilibrium in
approximately four months while Amodel AS-1133
HS resin requires over two years.
Property Data
Amodel ® PPA Design Guide
41