Effects of 3,4′‐oxydianiline on the structures and properties of a novel aromatic polyimide foam

Abstract

Abstract Aiming at the low volumetric shrinkage, a novel aromatic polyimide foam is successfully prepared from polymethane polyphenyl isocyanate (PAPI) and a poly(amic‐acid) precursor which has been synthesized from 3,4′‐oxydianiline (3,4′‐ODA) and pyromellitic dianhydride (PMDA). In this research, five polyimide foams, with different contents of 3,4′‐ODA, are comparatively studied including structural, thermal, mechanical, shrink, and degradation properties. The results indicate that the content of 3,4′‐ODA has minor influence on chemical structures, but significant influence on cell structures of the foams. With the increase of 3,4′‐ODA, the volumetric shrinkages, apparent densities and the compressive and flatwise tensile strengths of the materials decrease. The glass transition temperatures ( T g ) decrease from 301°C to 279°C, and the 5% weight loss temperatures ( T 5% ) increase from 323°C to 340°C. Through TG‐FTIR analysis, we can observe that the addition of 3,4′‐ODA has no influence on the pyrolysis mechanism of polyimide foams. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012