Molecular factors affecting solubility in rigid‐rod polyamides

Abstract

The solubility of a series of para‐linked, substituted phenyl, biphenyl, terphenyl, and quaterphenyl polyamides is reported. Most of these polymers are soluble in amide solvents without lithium chloride, and several are soluble in ethers and/or ketones. The results indicate that solubility in this class of polymers is affected by the position, polarizability and size of the substituents, enantiomeric purity, and the number of non‐coplanar biphenyl rings per repeat unit.

Synthesis, characterization, and water sorption properties of new aromatic polyamides containing benzimidazole and ethylene oxide moieties

“…It is well known that processability may be improved by the addition of flexible chains to the polyamide backbone, which enhance the molecular mobility, providing better solubility and reducing T g 8–11. For this particular purpose, ethylene oxide units have been extensively incorporated into polymers 12–15.…”

A novel synthetic route to rigid‐rod polyimides

“…After removal of the solvent in vacuo the material was recrystallized twice from isopropyl alcohol yielding long, colourless needles (19,3 After stirring and heating for 2 h, the warm solution was decanted from the iron powder.…”

New Polymer Syntheses Part 59. Synthesis and Characterization of New Polyamides and Copolyamides Containing Thianthrene Moiety and Based on Methyl- and/or Tertiarybutyl-Cyclohexanone in the Main Chain

“…Structural modification such as the introduction of (1) a bulky pendant substituent [3][4][5], (2) the nature of the parent chain (e.g. types of linkages and aromatic units) [6][7][8], (3) non-coplanar biphenylene moieties [9], and (4) flexible alkyl spacers [10] have been reported to enhance the solubility and to lower the phase transition temperatures. Copolymers having sulfone, imide, ether, and sulfide linkages lead to flexibility without compromising thermal stability [8,10,11,[12][13][14][15][16][17][18].…”