This invention relates to a process for polymerization, comprising (i) contacting, at a temperature greater than 35° C., one or more monomers comprising ethylene and/or propylene, with a catalyst system comprising a metallocene catalyst compound and an activator, (ii) converting at least 50 mol % of the monomer to polyolefin; and (iii) obtaining a branched polyolefin having greater than 50% allyl chain ends, relative to total unsaturated chain ends. The invention also relates to the branched polyolefins and functionalized branched polyolefins.