Separation of Parent Homopolymers from Poly(ethylene oxide) and Polystyrene Based Block Copolymers by Liquid Chromatography under Limiting Conditions of Desorption-2. Studies of Samples Obtained from ATRP and NMP
Abstract
Block copolymer synthesis often results in a complex polymer mixture containing not only the desired block copolymer macromolecules but also one or both parent homopolymers. Such complex polymer mixtures resulting from Atom Transfer Radical Polymerization (ATRP) and Nitroxide Mediated Polymerization (NMP) syntheses of PS-b-PEO-b-PS were characterized using Liquid Chromatography under Limiting Conditions of Desorption (LC LCD). The presence of PS homopolymer depends only on experimental synthesis conditions, such as the dilution of the reaction medium, the styrene/PEO molar equivalent ratio and the reaction time. Presence of residual PEO homopolymer is not only influenced by experimental synthesis conditions but also by the presence of unfunctionalized PEO in the corresponding PEO macro-initiator samples.