The Influence of Rigid and Flexible Monomers on the Physical-Chemical Properties of Polyimides

This article presents the synthesis and characterization of polyimides and copolyimides derived from rigid {[}4,4 `-(9-fluorenylidene) dianiline (FNDA) and 3,3 `,4,4 `-biphenyltetracarboxylic dianhydride (BPDA)] and flexible segments {[}4,4 `-(1,3-phenylenedioxy) dianiline (PDODA) and ethylenediaminetetraacetic dianhydride (EDTAn)], by polyaddition followed by thermal imidization of the polyamic acid. It describes the characterization of the polyimides and the polyamic acids in accordance to H-1 NMR, FTIR, GPC, and XRD analysis, as well as solubility, mechanical (DMTA and stress-strain tests), thermal (DSC and TGA), and electric properties. Among the homopolymers, FNDA-BPDA and PDODA-BPDA form free-standing films. The first presents higher T-g, thermal stability and Young's modulus. To tailor the properties copolyimides of FNDA, PDODA, and BPDA were synthesized. Young's modulus, T-g, thermal stability, dielectric constant, and solubility progressively increase with increasing amount of FNDA. (C) 2014 Wiley Periodicals, Inc. (AU)