Influence de la nature du solvant sur les propriétés physico‐chimiques des polyamides aromatiques en solution diluée

Abstract

Abstract The dilute solution properties of some aromatic polyamides like: poly(1,4‐phenyleneterephthalamide), (or poly(imino‐1,4‐phenyleneiminoterephthaloyl)), poly(parabenzamide), (or poly(imino‐1,4‐phenylenecarbonyl)), and some chlorinated derivatives of poly(1,4‐phenyleneterephthalamide) have been investigated. Solvents like 96% sulfuric acid, methanesulfonic and chlorosulfonic acid and also N,N ‐dimethylacetamide + LiCl have been used. An increase of the intrinsic viscosity and of the exponent of the viscosity law when we use methanesulfonic and chlorosulfonic acids has been observed and is explained by an increase of the rigidity and hydrodynamic diameter of the molecule. The measurements of the radius of gyration, and optical anisotropy confirm this. In N,N ‐dimethylacetamide, the molecules of poly(parabenzamide) exhibit an association which depends on parameters such as percentage of LiCl and temperature.