解説25. 高分子材料の劣化と耐久性
(1) 高分子の粘弾性挙動に伴う長期的観点での接着強度低下
2023 年 59 巻 12 号 p. 420-429
詳細
2023 年 59 巻 12 号 p. 420-429
Creep deformation is unavoidable for polymers even at room temperature. Therefore, it is very important to discuss the creep behavior of adhesively bonded joints. In order to understand the basics of creep behavior, viscoelastic models, such as Kelvin solid and Maxwell liquid, were explained. In addition, Norton’s creep power law and Monkman-Grant relationship for creep phenomenon in metal were described because the creep curves have similarities between different materials. In the case of adhesively bonded joints, creep becomes a big issue in long-term use. Therefore, test methods for evaluating deterioration in strength and toughness due to creep were explained. In general, the failure load and failure time have an inverse relationship for creep strength tests, and a threshold due to crack stop emerges for the creep toughness tests. However, a crack begins to progress again when other factors become dominant. Therefore, careful evaluation is required when the failure mechanisms change.
