Polymer characterization using on-line coupling of thermal field flow fractionation and hydrodynamic chromatography

The on-line coupling of thermal field-flow fractionation (ThFFF) and hydrodynamic chromatography (HDC) was used for the two-dimensional characterization of polymers and polymer blends. In the coupled system, distinct fractions of the solute band leaving the ThFFF channel were on-line injected into a HDC column. Since ThFFF separates polymers on the basis of the ratio of the thermal diffusion and molecular diffusion, whereas HDC separates only according to molecular mass, i.e., molecular diffusion: a two-dimensional separation of a polymer sample can be obtained with respect to size and thermal diffusion. The thermal diffusion coefficient can act as a measure of the chemical composition. The total analysis time for one polymer sample was about 30 min. The applicability of the coupled system to detect composition drift in copolymers was illustrated.