Gamma irradiation-induced degradation of silicone encapsulation

Silicone elastomers are widely used as encapsulants for electronic devices. They sometimes serve in extreme conditions, gamma irradiation, extraordinary temperature, and complicate vibration for instance. In the present study, gamma irradiation stability of silicone encapsulant was investigated by evaluating the material perfor-mance. The silicone encapsulant shows an increased crosslink density, tensile modulus and hardness, and a decreased elongation at break with increasing absorbed dose. Meanwhile, the melting temperature and dielectric constant show the similar tendency with the elongation at break. The moisture resistance, hydrophobicity and chemical structure on surface just slightly changed. It is inferred that the irradiation-induced crosslinking is the main reason for the deterioration of material performance. Dose rate effects of the materials were also investi-gated in the range of 2 Gy/s~10- 4 Gy/s.