Synthesis and Characterization of Novel Polyaspartimides Derived from 2,2'-Dimethyl-4,4'-bis (4-maleimidophenoxy)-biphenyl and Various Diamines

摘要

A novel bismaleimide, 2,2'-dimethyl-4,4'-bis (4-maleimidophenoxy) biphenyl, containing noncoplanar 2,2'-dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2'-dimethyl-4,4'-bis (4-aminophenoxy) biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m-cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymes were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X-ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g~(-1) in concentration of 1.0 g dL~(-1) of N,N-dimethylfornamide. All polymers are soluble in N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, pyridine, m-cresol, and tetrahydrofuran. The polymers except PASI-4, had moderate glass transition temperature in the range of 188 deg -226 deg C and good thermo-oxidative stability, losing 10% mass in the range of 375 deg -415 deg C in nitrogen.