Continuous viscometric, detection is based on the measurement of ressure drop in an on-line small capillary tube in which cErornatogra hic eluents flow at constant flow rate. This detector is ayways coupled with a concentration detector (usually refractometer) and located before it t o avoid back presrura in the refractometer. In order to obtain reliable information f o r polymer samples, it is general1 necessary to connect these two detectors to a computer whicx performs data acquisition and treatment.First we discuss the rroblem of shape, g?ometry and dimensions of the viscometer. Tge typical charactsristlcs are the result of a comproaise between contradictory hrgets, mainly small internal vblume !ow shear rate,and low prassure drop. It is shown that $oiseullle's lammar flow is only obtained when coiling radius of the measurement tube ? s greater than 6 cm which is not the cass inside tne refractometer. Accbrdingly, tiro pressura transducers are necessary t o eliminate pressure drop data comlng from refractorneter. LESEC, LECACHEUX, AND MAROTIn a second ,part, we show how to extract information from pressure variation data. By using conc?ntration data, pure solvent pressure and sample pressure it 1s possibl? to calculate intrinsic viscosity extrapolated to zsro concentration at,each,point of the chromato ram. By comparison rith intrinsic viscosity cf the pol mar use! for calibration, a correction of hydro& narcic v01une according : ? Benoit's universal calibration leads t o absolute aolecuiar welghts.In addition, for a linear polymor the knowled3~ of log [ q J versus log H leads to the determination of .'arkHouwin$ relationship coafficients. For branched polyaers. viscosity laws are curved aild the comparison betweer. the linear lar,corresponding to the linear equiyalent pol iiisr an$ the experimental law allows the daterminat:on ofl'the $ branching pirameter distribution.

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SYNOPSISIn this paper, the shape of chromatograms obtained by elution of copolymers with a mixture of solvent-nonsolvent of variable composition has been studied from a theoretical point of view. It is assumed that the thermodynamic quality of the mixture a t which the copolymer is eluted depends only on its composition and not on its mass and structure. If one characterizes the polydispersity in composition, assuming that each constituent obeys a molar mass distribution of the Zimm-Schulz type, one can draw the following curves: concentration of the copolymer versus eluant composition. They depend on three parameters, including composition of the copolymer and the polydispersity of each constituent. The most striking result is that the shape of the chromatogram changes dramatically when one increases the polydispersity of either constituents. For low polydispersities, one obtains a classical peak. For large polydispersities, the chromatogram has a minimum for the intermediate values of composition and presents peaks in the vicinity of the pure homopolymers. This can be explained easily by a qualitative argument.

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