Chemistry Reference
In-Depth Information
0
PS/N
2
- 313.11 K
PS/N
2
- 333.23 K
PS/N
2
- 353.15 K
-10
-20
-30
-40
0
10
20
30
40
50
p
[MPa]
Fig. 24 Variation of
T
g
as a function of pressure for the {N
2
PS} system. Calculations have been
made for 313.11, 333.23, and 353.15 K, using
z
=1.
Lines
are hand drawn through the points
Fig. 25 SEM pictures (50
m definition) of modified PS samples under CO
2
or N
2
gas pressure.
The structure of the modified PS presents different aspects depending on the use of CO
2
or N
2
as
blowing agent.
Left
: For the {CO
2
PS} system at 317.15 K, the structure of foam is apparent.
Right
: For the {N
2
PS} system at 313.12 K, there is no appearance of a foam structure; the surface
of the PS is only damaged by the gas pressurization
m
4 Conclusion
An experimental setup coupling a VW detector and a
pVT
technique has been used
to simultaneously evaluate the amount of gas entering a polymer under controlled
temperature and pressure and the concomitant swelling of the polymer. Scanning
transitiometry has been used to determine the interaction energy during gas sorption
in different polymers. The technique was also advantageously used to determine the
thermophysical properties (like isobaric thermal expansivity) of polymers in the
