A process for increasing MFR2 of a polyethylene copolymer or an ethylene plastomer or elastomer comprising: (I) extruding a copolymer of polyethylene copolymer having a density of 910 to 970 kg/m3 and an MFR2 of 1 and 100 g/10 min or an ethylene plastomer or elastomer having a density of 855 to 910 kg/m3 and an MFR2 of 0.5 and 100 g/10 min in the presence of 0.1 to 2 wt % of a non-peroxide radical initiator so as to produce a polyethylene copolymer having an MFR2 of 200 g/10 min or more, or an ethylene plastomer or elastomer having a MFR2 of 200 g/10 min or more.