SynopsisA new preparative liquid-phase chromatograph, operating at a high temperature (ISO"C), allowed us to fractionate a linear polyethylene sample in narrow fractions (polydispersity about 1.1). These fractions, characterized by viscosity, light scattering, osmometry, and GPC measurement.s, can be used to calibrate any analytical GPC, i.e., to determine the variation of molecular weight and axial dispersion versus the elution volume.

SynopsisA preparative liquid-phase chromatograph w&s built for the purpose of obtaining sufficiently large quantities of very narrow fractions of different polymeric species, such as polystyrene, PVC, polybutadiene, and polyethylene. This apparatus allows the fractionation of approximately 20 g of polymer per day; the fractions so obtained have polydispersities of about 1.1 over a very wide range of molecular weights. Polydispersities of less than 1.01 were obtained after recycling of the sample. DESCRIPTION AND CHARACTERISTICS OF THE PREPARATIVE CHROMATOGRAPHA preparative chromatograph can be divided into five components ( Fig. 1) which are (1) the pumping system; (2) the sample injector; (3) the columns; (4) the detector; (5) the fraction collector. We shall not describe in this paper the pumping system and the detector, which are directly based on the Waters analytical instrument.

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