PHYSICAL MODIFICATIONS FOR IMPROVED PEEL STRENGTH IN A HIGH-TEMPERATURE EPOXY ADHESIVE

The thermal performance of high-temperature thermoset adhesives is inv ariably gained at the expense of mechanical properties, particularly p eel strength. A microscopic study of failure propagation in adhesive j oints revealed that fibres within the bondline can affect the fracture path during peel failure in a commercially available modified epoxy a dhesive, developed for high-temperature use. This adhesive has been fu rther modified by the incorporation of polymer fibres and the resultan t adhesive joints have shown significant increases in peel strength co mbined with both increases and decreases in lap-shear strength, depend ing on the fibre orientation. These effects were measured from - 55 de grees C to + 180 degrees C. Improvements were also seen when larger jo ints, more typical of aerospace structures, were tested. (C) 1998 Else vier Science Ltd. All rights reserved.