Synthesis and characterization of new aromatic polyamides bearing crown ethers or their dipodal counterparts in the pendant structure. II. Benzo‐15‐crown‐5 and ortho‐bis[2‐(2‐ethoxyethoxy)ethoxy]benzene

This article describes the synthesis and characterization of two diacid monomers, each containing a benzo‐15‐crown‐5 subunit or its dipodal counterpart. Both novel monomers were reacted with technical aromatic diamines with Yamazaki's direct polyamidation method to render modified polyisophthalamides with high molecular weights containing side moieties of cyclic and acyclic ethylene oxide sequences. All the polymers were soluble in aprotic polar solvents and showed high glass‐transition temperatures in the range of 190–345 °C. The polymers with side crown ethers showed much higher glass‐transition temperatures than those with acyclic linear side ethylene oxide arms. The chemical composition, particularly with respect to the diamine and the open or closed character of the pendent ethylene oxide sequence, also affected other general properties such as the mechanical resistance, mechanical modulus, or water absorption. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4063–4075, 2006     

Synthesis and characterization of new aromatic polyamides bearing crown ethers or their dipodal counterparts in the pendant structure. I. Benzo‐12‐crown‐4 and ortho‐bis(2‐ethoxyethoxy)benzene

Two novel isophthalic diacid‐based monomers have been synthesized by inclusion in ring position 5 of a functionalized benzoylamine moiety. The functionalization includes a 12‐crown‐4 ether group fused with the benzene subunit and a dipodand substructure, formally a disubstitution of the benzene ring, with two sequences of ethyl‐terminated ethylene oxide units, which represent the open‐chain counterpart of the alicylic crown moiety. The polycondensation of the two diacids with five aromatic diamines yielded 10 new polyamides with crown or podand pendant substructures. The polyamides had previously been chemically characterized by NMR, IR, and elemental analysis. The polymers showed high glass transition temperatures of up to 349 °C, good thermal stability (T_{donset, N2} ≈ 400 °C), and improved solubility in organic solvents. The presence of acyclic or alicyclic oxyethylene sequences as crown ether or podand substructures and an additional amide side group per repeat unit made the polymers essentially amorphous and improved their water absorption ability in comparison with nonsubstituted polyamides. Water uptake values as high as 12% were observed at 65% relative humidity. All the polyamides showed a good film‐forming ability, and the mechanical properties of these films are considered to be satisfactory for experimental aromatic polyamides. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2270–2281, 2006