Rates of exchange of solvent in and out of crosslinked polystyrene beads

Abstract

Rate constants of exchange of solvent in and out of swollen crosslinked polystyrene beads have been determined by a 13C-NMR magnetization transfer method. The exchange rate constants for toluene in 10% crosslinked beads vary with particle diameter d as d −2. For dichloromethane in 1% crosslinked beads the rate constant dependence on particle size lies between d −1 and d −2. Rate constants of dichloromethane exchange decrease as swelling ratio decreases and percentage crosslinking increases from 1 to 20%. The method potentially can be applied to determine solute exchange rates in solid phase peptide synthesis and in gel permeation chromatography.