Environmental aging and deadhesion of siloxane-polyimide-epoxy adhesive

Adhesives are subject to environmental aging that degrades their strength and fracture toughness over time. Aging increases the rate of crack growth under fatigue loading, and can lead to deadhesion of an adhesive bond. In this study, an empirical model is constructed from peel test data that quantifies the rate of aging of a siloxane-polyimide-epoxy adhesive as a function of temperature and humidity exposure. An accelerated test methodology that accounts for both aging and fatigue is then proposed, and demonstrated using a case study.