Synthesis and Characterization of Organosoluble Copolyimides Based on 3,3′,4,4′‐Diphenylsulfonetetracarboxylic Dianhydride and a Pair of Aromatic Diamines Containing 1,2‐Bis(4‐Aminophenoxy)‐4‐tert‐Butylbenzene

Abstract

A series of copolyimides was synthesized from commercial 3,3¢,4,4¢-diphenylsulfonetetracarboxylic dianhydride with a pair of diamines, which contained 1,2-bis(4-aminophenoxy)-4-tert-butylbenzene. The intermediate poly(amic acid)s had the inherent viscosities of 0.52-1.52 dL/g and were thermally converted into copolyimides. These copolymers were soluble in a variety of organic solvents such as NMP, DMAc, and DMF, and almost all of them could even be dissolved in less polar solvents such as m-cresol, pyridine, and dioxane, showing a better solubility than corresponding homopolymers. Copolyimide films had tensile strengths of 87-160 MPa, elongations at a break of 9-12%, and initial moduli of 1.9-2.2 GPa. The glass transition temperatures of these copolymers were in the range of 262-288°C, lower than that of homopolymers. The copolyimides had 10% weight loss temperatures in the range of 495-522°C under nitrogen and 508-521°C under air atmosphere, and they left more than 43% residue even at 800°C in nitrogen. The thermal stability of copolymers was somewhat sacrificed due to the copolymerization, but they still belong under heat-resistant polymeric materials.

Comparative study on polyimides derived from isomeric diphenylsulfonetetracarboxylic dianhydrides

“…Among them, 4,4′-DSDA is available from the commercial sources and has been widely used. 25–28 Only Ding et al 14 reported a polyimide from 3,3-′-DSDA, but no properties other than thermo-oxidative stability were measured. Furthermore, to our best knowledge, no report dealing with 3,4′-DSDA and polyimides from 3,4′-DSDA has been appeared in the literature.…”