The long chain branching of polybutadienes (PB) was measured with gel permeation chroma-tography coupled to an automatically recording capillary viscometer. In this method the experimentalrelation [η] (V) was translated into the calibration curve [η] (VR) for the monodisperse species. The curve is combined with the universal calibration so that the molecular weight distributionand an additional parameter

e.g. the average branching factor of this samples may be obtained. Longchain branching molecular weight changes with polymerization conditions.