Effect of radiation processing on the viscoelastic behavior of hydroxyethylated guar (HEG) of molar substitution (M.S.) = 0.1: (a) unirradiated; (b) irradiated at 1 KGy; (c) irradiated at 2.5 KGy; (d) irradiated at 5 KGy; (e) irradiated at 10 KGy; (f) irradiated at 20 KGy; (g) irradiated at 50 KGy.