Synthesis and evaluation of polyimides derived from spirobisindane dietheranhydride

Polyimides derived from 5,5′‐[(2,2′,3,3′‐tetrahydro‐3,3,3′,3′‐tetramethyl‐1,1′‐spirobi[1H‐indene]‐6,6′‐diyl)bis(oxy)]bis‐1,3‐isobenzofurandione (spirobisindane dietheranhydride, SBIDA) and 20 plus aromatic diamines were prepared. The weight percentage of cyclic contaminants in each polyimide, estimated by gel permeation chromatography, ranges from 4 to 25%. The amount of cyclics formed in each polyimide depends on the distance and spatial orientation of the two amino groups on the aromatic diamines as well as the rigidity of the diamines. The formation of SBIDA‐containing polyimide was found to be catalyzed by alkali metal ions even when the reaction was conducted in m‐cresol. Thermal stability and glass transition temperature of those SBIDA‐derived polyimides were examined with thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Two promising compositions were scaled up and their mechanical properties were obtained. © 1993 John Wiley & Sons, Inc.