ポリエチレンの疲労強度に及ぼす熱処理の影響
The Influence of Annealing on Fatigue Strength in Polyethylene
北尾幸市
Kitao, Koichi
To investigate the influence of morphology on fatigue strength of polyethylene, the change in fatigue strength and relaxation behavior by annealing was evaluated using high-density polyethylene, which has few short branches, and medium-density polyethylene, which has many short branches. For medium-density polyethylene, which showed higher fatigue strength, the annealing had a small effect on β relaxation behavior and the fatigue strength was increased by annealing at 110℃. Alternately, for high-density polyethylene which showed lower fatigue strength, annealing decreased the fatigue strength and enlarged the intensity of β relaxation. It was thought that the fatigue strength of high-density polyethylene was dependent on entanglement by fine crystals and that the disappearance of that by annealing yielded lower fatigue strength and the enlargement of β relaxation intensity.
Key words: Polyethylene / Fatigue strength / Short branch / Annealing / Relaxation