Effect of structure on the thermal behaviour of bisitaconimide resins - Polyimides and Other High Temperature Polymers - page 179

Table 12.
Thermal behaviour of cured (at 200°C for 2 h) bisitaconimides

Bisitaconimide Temperatures (°C) Weight loss

(%)

Char yield (%)
(800°C)

T i T max T f

IA 218

404

231
449

249
518

6.9
51.7 42

IF 268

482

314
516

332
562

4
55

41

3.2.4. Bisitaconimide oligomers
Bisitaconimde oligomers based on 4,4'-diaminodiphenyl ether/1,4-bis(4-amino-
phenoxy) benzene and aromatic tetracarboxylic acid dianhydride were prepared
according to reaction Scheme 2.
The synthesis was carried out by reacting 0.01 mol of appropriate amine with
0.01 mol of itaconic anhydride in 20 mL dimethyl formamide. After stirring at
60°C for 3 h, 0.005 mol of aromatic tetracarboxylic acid dianhydride was added
and the reaction was continued for 3 h. Cyclodehydration of amic acid to imide
was carried out by acetic anhydride and anhydrous sodium acetate (4 h). The
imide resins were precipitated in ice-cold water, filtered, washed successively
with water, sodium bicarbonate solution, water and dried in vacuum oven at 50-
75°C. The structure and letter designation of these bisitaconimides are given in
Scheme 3.

Scheme 2. Reaction scheme for the synthesis of bisitaconimide oligomers.