title: Separation of poly(styrene-block-t-butyl methacrylate) copolymers by various liquid chromatography techniques.
abstract: 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.
authors.affiliation: Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
authors.forename: Tina
authors.initials: T
authors.lastname: Smigovec Ljubič
authors.forename: David
authors.initials: D
authors.lastname: Pahovnik
authors.forename: Majda
authors.initials: M
authors.lastname: Zigon
authors.forename: Ema
authors.initials: E
authors.lastname: Zagar
mesh_terms: D002850:Chromatography, Gel / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000737:chemistry*; D011108:Polymers / Q000302:isolation & purification*; D011137:Polystyrenes / Q000737:chemistry*
chemical_list: D008689:Methacrylates; D011108:Polymers; D011137:Polystyrenes; C116863:poly(butyl methacrylate)