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 (Ea) of the thermal curing were calculated using Ozawa and Kissinger method from DSC (Ea 103 KJ/mol and 106 KJ/mol). The Tg and T10% of the polyaspartimides are in the range of 199-280oC and 360-480oC respectively