Synthesis and characterization of new soluble polyaspartimides derived from bis(3-ethyl-5-methyl-4-maleimidophenyl)methane and various diamines

A series of new linear polyaspartimides was obtained via a Michael addition reaction from bis(3-ethyl-5-methyl-4-maleimidophenyl)-methane (BEMM) with various aromatic diamines in m-cresol in a 1:1 molar ratio. The molecular w eight and yield of these polymers tend to increase with increasing monomer concentration. It was observed that a maximum molecular weight was reached at around 0.72 mol 1(-1) of monomer concentration. Both the yield and the m olecular weight of the polymers increased with reaction times up to around 100 h. The inherent viscosities of the polymers varied from 0.42 to 0.70 dl g(-1). The polymers had number-average molecular weight and weight-average molecular weight in the range of 9400-20 000 and 24 000-68 000, respective ly. All polymers are amorphous and soluble in N-methyl-2pyrrolidone, N,N-di methylacetamide, DMF, dimethyl sulfoxide, pyridine, m-cresol, cyclohexanone and tetrahydrofuran, The polymers had high glass transition temperatures i n the range of 242-308 degreesC and good thermal stability - 10% weight los s temperatures in the range of 408-459 degreesC in air and 396-421 degreesC in nitrogen. (C) 2000 Elsevier Science Ltd. All rights reserved.