Preparation and characterization of bismaleimide monomers with various structures

Abstract

A series of bismaleimide monomers (BMI) with various structures containing flexible linkages was prepared and structural characterization of these compounds was carried out by elemental analysis, Fourier transform infrared spectroscopy, and 1H-NMR spectroscopy. The thermal behavior of these monomers (BMI(1-4)) was investigated by differential scanning calorimetry, polarized light microscopy and thermogravimetric analysis. The reactivity of the bismaleimide compounds is influenced by chemical nature of the bridge unit between the maleimide rings. The monomers were soluble in several organic solvents, the 10% weight loss temperatures were above 500 °C, and char yield at 700 °C ranged between 46 and 58% in nitrogen atmosphere. Birefringence in melting state was observed for two bismaleimides (BMI-3 and BMI-4) which could indicate a possible thermotropic liquid crystalline behavior. © 2012 Taylor &Francis.