The degree of peroxide induced chain extension of polyethylene (PE) as a result of free radical silane grafting proves to be of vital importance to the rate of formation and also the final degree of crosslinking of the PE network structure upon moisture curing. The differences in solid state structure (which determines the moisture diffusion rate into the polymer) and silane grafting efficiency of various PE types have been shown to play an important but a secondary role in the crosslinking of the resins.