Characterization of complex polymer systems by advanced methods of liquid chromatography with multiple detection

A. SISKOVA; M. M. YOSSEN; M. C. BRANDOLINI; J. R. VEGA

Cracow

Workshop; YES 2014. 5th Young European Scientists Workshop; 2014

Liquid chromatography under limiting condition of desorption (LC LCD) is an advanced method designed for a rapid separation of macromolecules according to their chemical composition or physical architecture but regardless of molar masses. Principle of this method is based on the selective action of the barrier injected into the column before the injection of the polymer sample. The barrier is a narrow zone of low molecular substances which causes the temporary adsorption of certain kind of macromolecules present in the sample. Since the eluent promotes the polymer desorption, then the species affected by the barrier are not fully retained. Additionally, the macromolecules unaffected by the barrier elute in SEC mode.LC LCD is a method suitable for separation of polymer mixtures containing two or more components. Three components polymer systems (e.g., a di-block copolymer contaminated by its parent homopolymers) require the use of two barriers, which are individually injected with some time delay and according to their effectiveness for stopping the different constituents. LC LCD is a great technique for the separation of all the components in a single run. Another practical application of LC LCD is the discrimination of macromolecular additives from polymer matrixes even at concentrations lower than 0.5%. Minor macromolecular additives may distort the measured molar masses, their dispersities and also the final use of the polymeric materials.The important conditions and also to some extent the limitations of LC LCD application are distinct adsorptivity of macromolecules to be separated and solubility of polymers under study in the mutually miscible solvents of different polarities.Evaporative light scattering (ELS) detector is frequently used as a concentration-sensitive detector in LC LCD. In this contribution we investigate the effectiveness of a differential refractometer plus a UV sensor as feasible detectors for analyzing the separation of di-block copolymers from their parent homopolymers through the LC LCD technique.