SYNTHESIS AND CHARACTERIZATION OF BISMALEIMIDES AND POLYASPARTIMIDES CONTAINING PYRIMIDINE/DITHIANE MOITIES

Bismaleimides containing pyrimidine and dithiane group were synthesized from the diamines APPB and APDB and maleic anhydride via bismaleiamic acid as the intermediate followed by cyclodehydration . The structure of the monomers was confirmed by FT-IR, ¹H-NMR and ¹³C-NMR spectral techniques. Further, a series of polyaspartimides were synthesized by addition reaction of bismaleimides with the prepared diamines. The polymers were characterized by using FT-IR, ¹H-NMR and ¹³C-NMR. All the polymers are soluble in aprotic solvents such as NMP, DMF, DMAc  and DMSO. The activation energies (E_a) of the thermal curing were calculated using Ozawa and Kissinger method from DSC (E_a 103 KJ/mol and 106 KJ/mol). The T_g and T₁₀%  of the polyaspartimides are in the range of 199-280^oC and 360-480^oC respectively.