SYNTHESIS AND CHARACTERIZATION OF NEW POLYIMIDES DERIVED FROM 4,9-DIAMINODIAMANTANE

This work reports the synthesis of new diamantane-based polyimides by the reaction of 4,9-diaminodiamantane (I) with various aromatic tetrac arboxylic dianhydrides. The polyimide film IVa has a low dielectric co nstant of 2.7 and a low moisture absorption of 0.205%. The number-aver age molecular weight ((M) over bar(n)) of polyimide IVa is 37 kg/mol. Dynamic mechanical analysis (DMA) reveals that polyimide IVa has only a glass transition at 308 degrees C on the temperature scale between 0 and 350 degrees C. The glass transition temperatures of the polyimide s were also found to be 295-325 degrees C by means of a differential s canning calorimetry (d.s.c.). The polyimide IVa had tensile strength a t breakage of 68.4 MPa and initial modulus of 2.0 GPa. The temperature s of polyimides at a 5% weight loss ranged from 432 to 488 degrees C i n air and from 489 to 530 degrees C in N-2 atmosphere. The polyimide I Va is soluble m-cresol. (C) 1998 Elsevier Science Ltd. All rights rese rved.