This invention relates to a process for preparing a coupled copolymer comprising heating at least one polyolefine comprising ethylene and optionally at least one co-monomer said polyolefine having a molecular weight distribution of less than or equal to 3 and a coupling amount of at least one poly(sulphonyl) azide to the decomposition temperature of polyazide for a period sufficient to decompose at least 80 weight percent thereof and to produce coupled copolymer having a viscosity and shear frequency of 0.1 rad/sec greater than 5%. This invention also includes coupled copolymers as well as articles such as pipes, bottles, tubes, etc., made by them.