Radiation effects of paraffins as polymer model compounds—III. Crosslinking determination by mass analysis

Abstract

The molecular weights of 60Co γ-irradiated n-C 20H 42 and n-C 24H 50 was analyzed by a mass spectrometer. Both saturated and unsaturated monomer, dimer and trimer molecules were well observed for normal paraffins irradiated in their crystalline states at both -77 and 25°C. In addition to trimer products, higher oligomeric molecules such as tetramer and pentamer were able to be observed when they were irradiated in liquid state at 55°C. The higher the molecular weight, the higher the concentration of unsaturation. This is emphasized in liquid state more than in solid state. Therefore, it has been strongly suggested that the molecules with unsaturation produced by irradiation are highly reactive with other molecules, compared with saturated molecules. On the other hand, the chain scission products were scarcely observed in both crystalline and liquid state irradiation. The G-value of chain scission producing fragments with more than trimer units was estimated to be negligible.