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The Scientific World Journal
Volume 2012, Article ID 932609, 9 pages
Research Article

Separation of Poly(styrene-block-t-butyl methacrylate) Copolymers by Various Liquid Chromatography Techniques

1Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
2Center of Excellence for Polymer Materials and Technologies, Tehnološki Park 24, 1000 Ljubljana, Slovenia
3University College for Polymer Technology, Glavni trg 1, 2380 Slovenj Gradec, Slovenia
4EN-FIST Centre of Excellence, Dunajska 156, 1000, Ljubljana, Slovenia

Received 25 October 2011; Accepted 24 November 2011

Academic Editors: D. M. Milojkovic-Opsenica and M. Sajewicz

Copyright © 2012 Tina Šmigovec Ljubič et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The separation of a mixture of three poly(styrene-block-t-butyl methacrylate) copolymers (PS-b-PtBMA), consisting of polystyrene (PS) blocks of similar length and t-butyl methacrylate (PtBMA) blocks of different lengths, was performed using various chromatographic techniques, that is, a gradient liquid chromatography on reversed-phase (C18 and C8) and normal-phase columns, a liquid chromatography under critical conditions for polystyrene as well as a fully automated two-dimensional liquid chromatography that separates block copolymers by chemical composition in the first dimension and by molar mass in the second dimension. The results show that a partial separation of the mixture of PS-b-PtBMA copolymers can be achieved only by gradient liquid chromatography on reversed-phase columns. The coelution of the two block copolymers is ascribed to a much shorter PtBMA block length, compared to the PS block, as well as a small difference in the length of the PtBMA block in two of these copolymers, which was confirmed by SEC-MALS and NMR spectroscopy.