Soluble aramid containing ether linkages: Synthesis, static and dynamic light scattering studies

Aromatic polyamide was synthesized via condensation polymerization of 4,4 '-oxydianiline and isophthaloyl chloride using N,N '-dimethyl acetamide as solvent under anhydrous conditions. Aramid has been studied by laser light scattering (LLS) in dimethyl sulfoxide, a thermodynamically good solvent at 20 degrees C. Static and dynamic light scattering studies permitted to determine the weight average molecular weight < M-w >, radius of gyration < R-g > second virial coefficient A(2), the hydrodynamic radius R-H and the diffusion coefficient D. Light scattering experiments were conducted at five concentrations ranging from 0.2 to 2 g/L. This LLS method should also be very useful in the study of aggregation or association in a polymer system as long as the large clusters are reasonably stable in time. The intensity autocorrelation function obtained on the quasi-elastically scattered light showed a simple diffusive relaxation mode. The ratio of radius of gyration to the hydrodynamic radius, i.e., < R-g >/< R-H > similar to 1.5, indicates that the polyamide chain has coil conformation in DMSO at 20 degrees C. (c) 2008 Elsevier B.V. All rights reserved.