Synthesis and characterization of new functional bismaleimides

Functional bismaleimides containing gamma-lactone, carboxyl, aldehyde, hydr oxyl, azomethine or cinnamoyl groups were synthesized from maleimido benzoi c acid via its acid chloride with phenolphtaleine, 5,5'-methylene-bissalicy lic acid, 5,5'-methylene-bissalicylaldehyde, glycerol, tartaric acid and 3, 4-bis(hydroxyethan-2-tioether)-rho-maleimidobenzoic acid, by simple condens ation or polymer analogous reactions on some of these reactive bisimides. The monomers were characterized by IR, H-1-NMR and elemental analysis. The DSC curves of all the samples showed an exotherm in the temperature range o f 134-310 degrees C, which is attributable to curing reactions. Thermogravi metric analysis of the uncured resins indicated good thermal stability and a char yield of bismaleimide resins in accordance with the calculated C/H r atio. Their relative thermoxidative stability was evaluated by isothermal g ravimetric analysis.