The long chain branching of polybutadienes was measured with a gel permeation chromatog-raph coupled to an automatically recorting capillary viscometer. In this method the experimental relation (η) (V) was transformed to the calibration curve (η) (VR) for the monodis-perse species. The curve is combined with the universal calibration to proviel the molecular weight distribution and an additional parameter

i.e. g

the average branching foctor in this sample. The critical molecular weight at which long chain branching appear changes with polymerization conditions.