AbstractThe hydrodynamic behaviour of polydisperse branched copolymers of methyl methacrylate with a small amount of ethylene dimethacrylate was investigated in several solvents possessing different “solvent power”. It was found that with increasing degree of branching the viscometric expansion coeficient α 3[η],bof these copolymers decreases compared with the expansion of the linear analogs α 3[η],l(before the gel point α 3[η],b/α 3[η],l≈ 0,5). This phenomenon is demonstrated to be useful in the application of viscometry as a method of estimation or deter