“…For polymers with quaternary carbon atoms in the main‐chain, such as poly(α‐methylstyrene),5 chain scission is the most important reaction, with little or no cross‐linking. However, when the polymer contains a hydrogen atom adjacent to the side‐chain, as in polystyrene (PS),5–10 the main effect of γ‐irradiation is cross‐linking, often with smaller amounts of chain scission. With the absence of side‐chains, such as in linear polyethylene (PE),11–17 cross‐linking tends to totally dominate the radiation chemistry, with chain scission suggested to be negligible.…”