1. “Petru Poni” Institute of Macromolecular Chemistry, , Iasi, 700487 Romania;2. Institute of Thin Film Technology and Microsensorics, , Teltow, 14513 Germany;3. Fraunhofer Institute for Applied Polymer Research, Science Campus Golm, , Postdam, 14476 Germany
Abstract:
The influence of different substituents on the optical properties of poly(amide imide)s and polyimides is systematically investigated. All of the polymers exhibit good solubility and film‐forming ability, high thermal stability, and glass transition temperatures of 162–209 °C for poly(amide imide)s and of 209–274 °C for polyimides. The optical transmittance of the films at 450 nm is above 80% for all the studied polyimides and poly(amide imide)s containing benzonitrile units linked in the 2,6‐position. The values of refractive index for poly(amide imide)s are in the range of 1.623–1.748 and for polyimides in the domain of 1.672–1.768.
