Separation of parent homopolymers from poly(ethylene oxide) and polystyrene-based block copolymers by liquid chromatography under limiting conditions of desorption – 1. Determination of the suitable molar mass range and optimization of chromatographic conditions

Abstract

We studied molar mass limits for the LC LCD separation of parent polystyrene (PS) and poly(ethylene oxide) (PEO) homopolymers from PEO/PS based block copolymers and we identified optimized chromatographic conditions. Time delays between barriers and sample injections were 0–2–3′10. Eluent was composed of dimethylformamide (DMF) 40wt.% and 1-chlorobutane (CLB) 60wt.%; Barrier 1 (B1), which retained block copolymer, was composed of 100wt.% CLB and Barrier 2 (B2), which retained PEO, was a mixture of DMF and CLB, which proportions were adjusted to studied block copolymers. With B2 composed of DMF 23wt.% and CLB 77wt.%, we obtained successful separation of PS23K-b-PEO35K-b-PS23K (56.5wt.% of PS, the subscripts indicate the molar mass in kgmol−1 of each polymer part in the block copolymer) from its parent homopolymers. With B2 adjusted to DMF 30wt.% and CLB 70wt.%, PS2.3K-b-PEO3.1K (42.6wt.% of PS) was also efficiently separated from its parent homopolymers.