Synthesis and characterization of fluorinated copolyetherimides with CH2C6F13 side chains based on the ULTEM™ structure

Abstract

Step polymerization of bisphenol-A diphthalic anhydride (BAPA) with various mixtures from m-phenylene diamine (m-PDA) and 2-(perfluorohexylmethyl)butan-1,4-diamine (TFD) led to hydrophobic copolyetherimides bearing R F = -CH 2 -C 6 F 13 side chains that were characterized by NMR, elementary analysis, DSC, TGA and surface energy analysis. By increasing the TFD unit%, the glass transition temperature (T g ) decreases according to the Fox equation from 217 8C (m-PDA 100% and TFD 0% like in ULTEM TM 1000) to 113 8C (m-PDA 0% and TFD 100%). Similarly, the surface energy (g s ) decreases from 45.3 mJ m À2 to 27.4 mJ m À2 . The thermal decomposition temperature (T d for 5% weight loss under argon) is slightly affected by introducing TFD units compared with T d for ULTEM TM and it is close to 400 8C. The best compromise between thermal stability, hydrophobic and organophilic properties as well as the ability to form a soft nonporous film by the cast-evaporating method led us to select the copolyetherimide with m-PDA 25% and TFD 75% for which T g = 121 8C, T d = 400 8C and g s = 30.8 mJ m À2 . # 2005 Published by Elsevier B.V.