Molecular characterization of alpha,beta-poly[(N-hydroxyethyl)-DL-aspartamide] by light scattering and viscometry studies

alpha,beta-poly[(N-hydroxyethyl)-DL-aspartamide] (PHEA) is a new synthetic polymer which is of interest in biomedical applications. In this paper, the molecular characterization of PHEA by multi-angle laser light scattering a nd viscometry off-line and on-line to a size exclusion chromatography syste m is reported. These techniques furnish an exhaustive and consistent charac terization of the PHEA polymer. The fractionation of the PHEA macromolecule s was relatively simple. Using an aqueous mobile phase of medium ionic stre ngth, the elution was substantially regular and the macromolecules were not aggregate. The molar mass M of four PHEA samples approximately ranges from 46 to 53 K g/mol, the intrinsic viscosity [eta] ranges from 0.22 to 0.26 d l/g and the gyration radius R-g is also estimated. Both the slopes of the [ eta] = f(M) and R(g)f(M) power laws prove that PHEA macromolecules in aqueo us solution are flexible coils. Besides, the second virial coefficient valu e proves that the used mobile phase is a good solvent for PHEA. The molecul ar characterization of PHEA was also performed through conventional SEC and universal calibration and the estimated molar mass was substantially highe r than that evaluated by absolute methods. (C) 2000 Elsevier Science Ltd. A ll rights reserved.