Chemistry Reference
In-Depth Information
Scheme 1. Reaction sequence for the synthesis of bisitaconimides.
oping polymers based on annually renewable resources. Itaconic acid derivatives
homopolymerise by an addition-type reaction more readily than 1,2-ethylene de-
rivatives (e.g. maleimide or nadimide) resins. There is thus a need to investigate
addition polyimides based on these monomers.
The main focus of present studies was to examine the effect of structure on cur-
ing characteristics and thermal behaviour of itaconimide resins. The synthesis of
bisitaconimides was carried out in two steps according to the reaction Scheme 1.
Bisitaconimides of varying backbone structure and varying molecular weight
were synthesized by using aromatic amines having ether, sulfone, phoshine oxide,
amido group or fused aromatic ring structure. The effect of partial isomerisation
of bisitaconimide to biscitraconimide on thermal behaviour was also investigated.
2. EXPERIMENTAL
2.1. Materials
Chloroform, toluene (Qualigens), phosphorus pentoxide (P
2
O
5
), N,N'-dimethyl
formamide (Merck), itaconic acid (Aldrich), 4,4'-diaminodiphenyl sulfone (S
p
),
3,3'-diaminodiphenyl sulfone (S
m
), 4,4'-diaminodiphenyl ether (Fluka) (E), 1,3-
bis(3-aminobenzamide)benzene (A) and 9,9-bis(4-aminophenyl)fluorene (Mon-
santo) (F) were used as received. Acetone (Qualigens) was kept over anhydrous
potassium carbonate for 24 h and distilled before use. Tetrahydrofuran (THF)
(Central Drug House, New Delhi) was refluxed over stannous chloride and then
distilled before use. Acetic anhydride (British Drug House, London) was distilled
before use and sodium acetate (Sarabhai Chemicals, Vadodara) was fused by
heating and stored in a dessicator.
The amines 2,2'-bis[4-(4-aminophenoxy) phenyl] propane (P), 1,3-bis(4-
aminophenoxy) benzene (R), 1,4-bis (4-aminophenoxy) benzene (H) [4], tris(3-
aminophenyl)phosphine oxide (T) and bis(3-aminophenyl)methyl phosphine ox-
ide (B) were prepared according to the procedure reported elsewhere [5, 6].
2.2. Synthesis of bisitaconimides
Itaconic anhydride was prepared from itaconic acid by using phosphorus pentox-
ide (P
2
O
5
) as a dehydrating agent and chloroform as solvent with yield = 80%,
melting point = 69-70°C.
In a typical synthesis of bisitaconimides, 0.005 mole of diamine was dissolved
in 20 mL acetone and itaconic anhydride (0.011 mol) was added slowly with stir-
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