Molecular weight and TLC studies on the gamma degradation of some poly(methyl methacrylate) in the absence and presence of N,N-dioxalyl p-aminobenzene sulphonic acid and its iron (II) complex

Abstract

Protection of some poly(methyl methacrylate) samples against gamma rays has been investigated in the absence and presence of N,N-dioxalyl p-aminobenzene sulphonic acid and its iron (II)-complex. The pure PMMA (without additives), PMMA-ligand and PMMA-iron complex composite samples were irradiated with gamma rays for different exposure doses (5, 15, 25, 35, 50, 75 and 100 KGy). Viscosity average molecular weights ( M v -values) and thin layer Chromatographic measurements were carried out after each irradiation dose. The maximum protection against gamma ray is found when 7% of the organic ligand or its iron complex is used in the polymer matrix. The radiation chemical yield for main chain scission ( Gs) is calculated and has its lower values in the case of the organic ligand which means that the protection is stronger in the case of the organic ligand than its iron complex. From TLC studies, it is noticed that both the R f -values and polydispersity of the PMMA samples increase with increasing exposure dose.