Chemistry Reference
In-Depth Information
Table 2.
Thermal characteristics of polyimides
VA-VG
Polymer
T
g
, °C
T
10%
, °C (TGA)
T
dec
-T
g
, °C
air
argon
air
argon
A
390
600
665
210
275
B
395
610
665
215
270
C
365
625
675
260
310
D
385
605
655
220
270
E
360
580
645
220
285
345
565
610
220
265
F
G
350
575
610
225
260
Table 3.
Mechanical and dielectric characteristics of polyimides VA-VG
ε′
At humidity
Polymer
Tensile properties of films (25°C)
E, GPa
0%
50%
σ
, MPa
ε
, %
A
84.3
2.85
7.5
2.80
3.25
86.6
2.50
8.0
2.80
3.14
B
C
85.4
3.03
3.6
2.75
2.95
D
81.9
2.80
7.0
3.10
3.44
E
78.3
2.28
6.0
2.95
3.25
F
78.3
2.28
6.0
3.06
3.32
G
68.0
2.50
4.0
2.72
2.89
All phenylated PIs exhibit an excellent thermal stability (Table 2): temperatures
corresponding to the 10% weight loss under argon vary from 610 to 675°C. The
corresponding values in air are lower by 50-65°C and lie in the range from 565 to
625°C. Wide ranges between the decomposition and glass transition temperatures
(T
dec
-T
g
) of phenylated PIs indicate that, in principle, these polymers may be proc-
essed by compression molding.
All
polymers form films (Table 3). The tensile strength σ of these
films ranges from 68.0 to 86.6 MPa, elastic modulus E is between 2.28 and 3.03
GPa, and elongation at break ε is in the range from 4 to 8%. As can be seen in
Table 3, the elastic moduli of all the tested polymers are high and, for some poly-
mers, they are comparable to those of Kapton [25] and Ultem (2.96 GPa) [26].
The tensile strength of phenylated polymers is lower than that of Kapton (172
MPa) and of Ultem (105 MPa) [26]. However, for the majority of the synthesized
polymers, relative elongation at break
VA-VG
ε
is lower than that for commercial
polyimide materials (60-70%).
Search WWH ::
Custom Search