SynopsisA new method for rapid evaluation of long-chain branching (LCB) in polymers was developed. The crude GPC chromatogram and the measured value of intrinsic viscosity of the whole polymer are the only data required. By using trial and error in combination with graphic analysis, the threshold value Mo and average molecular weights M w and Mn, as well as LCB can be simultaneously evaluated. The advantage of this method lies in avoiding predetermination of the Mo for a given resin. The results obtained by this method for NBS Branched Polyethylene Standard Reference Material SRM 1476 and for a branched cis-1,4-polybutadiene sample were in good agreement with those given by the conventional Ram-Miltz method.