Analysis of poly(bisphenol A carbonate) by size exclusion chromatography/matrix-assisted laser desorption/ioinization. 1. End group and molar mass determination

The determination of molar mass (MM) data for polydisperse polymers by SEC/ MALDI involves the fractionation of samples through analytical size exclusi on chromatography (SEC). Selected SEC fractions are then analyzed by matrix -assisted laser desorption/ionization time-of-flight (MALDI-TOF) and the ma ss spectra of these nearly monodisperse samples allow the determination of the average molar masses, The SEC/MALDI procedure has now been applied to t wo polycarbonate samples, PC1 and PC2, The results show that the MALDI spec tra of the SEC fractions allow not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determinati on of their average molar masses. Two slightly differing SEC calibration pl ots were obtained, due to the smaller hydrodynamic volume of the polycarbon ate cyclic chains with respect to the linear ones, In agreement with theory , the ratio (M-cycle/M-linear)v(e) at a fixed elution volume was found to b e 1.22, independent of the molar mass values, Copyright (C) 1999 John Wiley & Sons, Ltd.