Effects of 1--Ray Irradiation on Polymers. (I) Effects of 7-Ray Irradiation on Elongated Filaments of

The effects of 7-ray irradiation in vacuum and in air on physical properties have been studied of the high and low density polyethylene filaments elongated to various degrees. The gel fraction of the vacuum-irradiated filaments increased with dose and was independent of the degree of elongation. The low density polyethylene irradiated in air was insoluble at 8.2x1000r and 1.5x107 r, whereas at a higher dose it was soluble in xylene of 80°C except the samples of the low degree of elongation. The high density polyethylene irradiated in air dissolved in xylene of 120°C for all radiation doses used. Using a theory proposed by Charlesby regarding the relation between solubility and dose, our experimental curve was found to be in an approximate agreement with the theoretical curve of f=0.5. G-values of crosslinking at the gelation point was 4.2 for the low density polyethylene and 4.9 for the high density polyethylene. The density of these filaments increased slightly with dose in vacuum-irradiation, and remarkably in air