LIGHT-SCATTERING STUDY OF AN AROMATIC POLYAMIDE-HYDRAZIDE POLYMER

In the reported experiments, the aromatic polyamide-hydrazide, Monsanto X-500, has been studied by light scattering in dimethyl sulfoxide, a thermodynamically good solvent. The unperturbed dimensions, (left angle bracket r//0**2 RT AN BR av/M)** one-half equals 1. 93 multiplied by 10** minus **8 at 25 degree C, indicate a rather highly extended chain. The persistence length falls in the range 35-63 A, which corresponds to a length of between two and four formula units. This is considerably smaller than the values which have been reported for the aromatic polyamides, poly(p-benzamide) and poly(p-phenylene terephthalamide). X-500 appears to approximate coil-like behavior at a molecular weight of 45,000. Theoretical predictions, based upon the left angle bracket r//0**2 RT AN BR /bL ratio, are compared with the observation that no evidence for an anisotropic phase has been found in X-500 solutions in dimethyl sulfoxide at polymer volume fractions ranging from 0. 12 to 0. 19 (depending upon the concentration of added LiCl).