Advanced synthetic polymers represent important group of modern, high-performance materials. Here belong complex polymers (COP) and complex polymer systems (CPS). COP exhibit more than one dispersity (distribution) in their molecular characteristics - molar mass, chemical structure and physical architecture. Their typical representatives are various kinds of copolymers and functional macromolecules. CPS comprise the two and multicomponent blends of macromolecules and block copolymers containing their parent homopolymers. Molecular characterization of both COP and CPS is an exacting analytical challenge because the analytes must be separated. At present, size exclusion chromatography/gel permeation chromatography (SEC/GPC) dominates the area. Though SEC/GPC is a marvelous method, it cannot give quantitative data on molecular characteristics of COP and of most CPS because the size of macromolecules in solution depends on all molecular characteristics of macromolecules to be separated. Moreover, the separation selectivity of SEC/GPC is fairly limited and both low detector sensitivity and sample capacity of SEC/GPC does not enable to characterize minor (solve the problem, coupled methods of polymer HPLC were introduced, which combine exclusion – entropic, and interaction – enthalpic retention separation mechanisms. Two of the coupled methods of polymer HPLC, namely liquid chromatography under critical conditions (LC CC) and liquid chromatography under limiting conditions (LC LC) of enthalpic interactions will be presented, compared and critically evaluated in the contribution with the conclusion that LC CC is preferable for oligomers and for binary blends of macromolecules with molar mass below about 10 kg/mol whereas LC LC has no upper molar mass limit but its performance may be not sufficient for low oligomers. The sample recovery represents an important limitation of LC CC of macromolecules with high molar mass. In contrast to LC CC, LC LC is robust and user-friendly. LC LC enables to separate even four-component CPS in one single step and can be easily engaged in the two-dimensional polymer LC.
Presenting author:
Dušan Berek
Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 84541 Bratislava, Slovakia
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Authors:
Dušan Berek - Polymer Institute, Slovak Academy of Sciences, SIovakia
