Chemistry Reference
In-Depth Information
Pyromelitimide can also add to double bonds to form polyimides [
97
]:
O
O
O
n
H
N
N
H
+
n
base
S
O
O
O
O
O
O
N
N
S
n
O
O
O
Polyimides also form by photo additions of aliphatic or aromatic bis maleimides to benzene [
98
].
The reactions involve 2 + 2 cycloadditions that yield homoannular diene intermediates. Diels-Alder
additions follow and result in formations of the polymers:
O
O
O
O
h
ν
+
N
N
R
N
R
N
O
O
O
O
O
O
N
N
+
R
Head-to-head and tail-to-tail structire
O
O
n
Diels-Alder reactions yield other polyimides, as, for instance, the following [
99
]:
O
O
+
O
N
N
O
O
O
O
O
O
N
O
N
O
O
n
