New high pressure polymerization and simultaneous processing for polyaminoimide from aromatic diamine and bismaleimide

The simultaneous polymerization and processing under high pressure was carried out by using a piston-cylinder type hot pressing apparatus. Before the polymer synthesis, the Michael addition of aniline to N-phenylmaleimide was performed under high pressure as a model reaction, giving N,N'diphenylaspartimide. The Michael-type polyaddition of 4,4'-methylenedianiline to the 4,4'-bismaleimidodiphenylmethane under 150-820 MPa at 180-300 deg C for 20-40 h afforded the linear polyaminoimide having inherent viscosities in the range of 0.2-0.8 dl g exp --1 . When the polymerization was carried out at higher temperature, the crosslinked polymer was produced. The polymerization under higher pressure required higher temperature. The crosslinked polymer synthesized under high pressure was very hard resin with Vickers hardness of 330-360 MPa and high modulus ( > 1.5 GPa), compared with the polymer obtained under ordinary pressure.