Comprehensive Molecular Characterization of Complex Polymer Systems by Sequenced Two-Dimensional Liquid Chromatography. Principle of Operation

Abstract

It is shown that numerous complex polymer systems consisting of macromolecules, which exhibit not only distinct sizes but also chemical composition, can be comprehensively characterized by a novel simple and efficient method of sequenced two-dimensional liquid chromatography. In the first step, macromolecules are separated according to their chemical composition, irrespectively of their molar mass, with help of the unconventional method of liquid chromatography under limiting conditions of desorption. Thusobtained fractions are in their entireties successively online forwarded into the size exclusion column for separation according to their molar mass. The effectuation of procedure is elucidated.

Separation of Parent Homopolymers from Nonpolar Block Copolymers by Means of Liquid Chromatography under Limiting Conditions of Enthalpic Interactions

“…The combination of LC LC techniques with other physical methods renders a powerful tool for comprehensive molecular characterization of complex polymer systems. The fractions obtained with help of LC LC can be forwarded one by one or jointly online into the SEC/GPC column so that molar mass averages and dispersities of all sample constituents are independently determined. The presence of a poor solvent barrier in samples separated with the help of LC LCU or especially a nonsolvent barrier in LC LCI should be considered in such 2D approaches.…”

Liquid chromatography under limiting conditions of desorption 6: Separation of a four‐component polymer blend

“…Obviously, minor additives could be easily identified at their relative concentrations even in the range of 1%. It is anticipated that preparative LC‐LCD would allow acquisition of sufficient amount of material for further molecular characterization, not only by sequenced 2D LC and pyrolytic GC but also by conventional IR or NMR spectroscopy. The results further endorse our previous observation that the LC‐LCD retention volumes of polymers are largely independent of their both overall and relative concentration in blend.…”

“…The high sample capacity of LC‐LCD enabled identification of minor macromolecular constituents in multicomponent polymer blends. Sequenced 2D liquid chromatography , which combines the present LC‐LCD system with the GRAM SEC column, can be applied to comprehensive molecular characterization of complex polymer systems with constituents of quite different polarities. The blend constituents mutually hardly affected their retention/elution, which may be important in preparative separations.…”

“…The band broadening effect of the SEC eluted sample is to be considered. The resulting method is denoted as sequenced 2D polymer liquid chromatography, (S2D‐LC) . As known, most 2D polymer HPLC procedures necessitate slow separation in the first‐dimension column followed with the high‐speed SEC.…”

Liquid chromatography of synthetic polymers under critical conditions of enthalpic interactions 4: Sample recovery

“…The LC CC apparatus is schematically shown in Fig. A, while the sketch of the 2D‐like arrangement of LC CC × SEC, similar to the recently developed sequenced 2D LC is displayed in Fig. B.…”