POST-GAMMA IRRADIATION CROSS-LINKING OF POLYETHYLENE TAPE BY ACETYLENE TREATMENT

The feasibility of enhancing cross-linking in drawn polyethylene tape by a two-stage process involving first irradiation and second exposure to acetylene gas, has been established. A number of variables have be en investigated; a dose of 50 kGy gamma irradiation in vacuum at -196- degrees-C followed by exposure to 1 atm acetylene for 36 h results in a cross-linked product with far superior creep performance to that of the untreated tape without loss of tensile modulus or strength. The tr eatment is particularly effective for the improvement of creep perform ance at 100-degrees-C. It is also shown to be slightly superior to bot h irradiation in vacuum and irradiation in an acetylene atmosphere, ea ch under optimum conditions.