Imidization and interdiffusion of poly(amic ethyl ester) precursors of PMDA/3,4′-ODA

✍ Scribed by Nancy C. Stoffel; Edward J. Kramer; Willi Volksen; Thomas P. Russell

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 311 KB
• Volume: 36
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19980930)36:13<2247::aid-polb1>3.0.co;2-q

✦ Synopsis

Para-, meta-, and mixed isomeric poly(amic ethyl ester) precursors of the polyimide based on pyromellitic dianhydride (PMDA) and 3,4 -oxydianiline (3,4 -ODA) were synthesized. The intrinsic viscosity of each of the isomers was measured in an NMP solution and found to be less than corresponding isomers derived from PMDA and 4,4-oxydianiline (4,4 -ODA) precursors with comparable molecular weight. The imidization and solvent retention were measured as a function of imidization temperatures, T i using forward recoil spectrometry (FRES). For samples cast from a single solvent, either N-methyl pyrrolidone (NMP) or dimethyl sulfoxide (DMSO), no difference was observed in the temperature-dependent imidization behavior between the isomers. In all cases the imide fraction f increased as T i increased, and reached a value of unity, i.e., full conversion at 400ЊC. At the same T i , samples cast from DMSO showed a slightly higher f than samples cast from NMP. FRES and time of flight FRES (TOF-FRES) were used to measure the interdiffusion distance, w, of deuterium-labeled tracers into nondeuterated base layers of the polyimide of PMDA/3,4-ODA treated at various T i . The primary determinant of w for all isomers was T i , and the particular isomer used as either the base or the tracer molecule did not seem to affect w.