The synthesis of ethene/propene macromers with a high amount of sterically unhindered vinyl groups is described. These macromers are incorporated as long-chain branches into polyethylene (PE). The remaining low molecular fractions were removed by Soxhlet extraction. Up to 60 wt.-% macromer was included, which leads to comb-like molecular topographies that distinctly affect the rheological behavior. The thermal activation energy increased significantly and the zero shear-rate viscosity lin enhancement factor eta(o)/eta(lin)(o) was also changed noticeably.