Preparation of Nanoporous Polyimide Films from Poly(urethane-imide) by Thermal Treatment

✍ Scribed by P. Santhana Gopala Krishnan; Chia Zheng Cheng; Yeo Swee Cheng; Jimmy Wu Chi Cheng

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 248 KB
• Volume: 288
• Category: Article
• ISSN: 1438-7492
• DOI: 10.1002/mame.200300030

✦ Synopsis

Abstract

Nanoporous polyimide films were prepared in two steps. The first step is the preparation of poly(urethane‐imide) films by casting blend solutions containing various weight percentages of poly(amic acid) and phenol blocked polyurethane prepolymer (from 1,6‐hexamethylene diisocyanate and poly(ethylene glycol)). Three poly(amic acid)s were obtained from biphenyltetracarboxylic dianhydride (or) 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride with 1,4‐phenylenediamine (or) 2,5‐dimethyl‐1,4‐phenylenediamine. Poly(urethane‐imide) films were characterized by density and surface energy measurements, AFM, DSC, TMA, mechanical properties and TGA. In the second step, these films were thermally treated above 300 °C to give nanoporous polyimide films. During thermal treatment, less thermally stable urethane domains decomposed, leaving porous polyimide films. The presence of pores was confirmed by scanning electron microscopy (SEM). The dielectric constant of the polyimide film was found to decrease with increasing amounts of urethane content.

A nanoporous polyimide film.

magnified imageA nanoporous polyimide film.