Molecular characterization of statistical copolymers: 1. Potential and limitations of full adsorption-desorption procedure in separation of statistical copolymers

Dynamic integral desorption isotherms for a series of poly(methyl methacryl ate) homopolymers and poly(methyl methacrylate)-polystyrene statistical cop olymers were measured. Nonporous silica was the full adsorption-desorption (FAD) column packing and various adsorption-promoting and desorption-promot ing liquids were used. The aim of this study was to evaluate the applicabil ity of the FAD approach for separation of statistical copolymers. The effec ts of the adsorbing liquid and desorbing liquid nature were demonstrated on the positions and shapes of desorption isotherms. The desorption isotherms also strongly depended on both (co)polymer molar mass and copolymer chemic al composition. This indicates large fractionation potential of the FAD pro cedure. Simultaneously, the interference of both above parameters prevents the direct use of FAD for fractionation of the copolymers. It is anticipate d that the fractionation and/or reconcentration potential of the FAD proced ure can be very effectively utilized in combination of FAD with size-exclus ion chromatography and/or with gradient elution liquid adsorption chromatog raphy. (C) 2000 John Wiley & Sons, Inc.