Comparison of Two Accelerated Hot-Wet Aging Conditions of a Glass-Reinforced Epoxy Resin

Abstract

Two accelerated hot-wet aging tests of glass-reinforced epoxy resin were performed at 45 and 70°C at the same level of relative humidity (RH = 84%). Mechanical and physical properties of “dry” and differently saturated composites are compared. It has been found that the higher the conditioning temperature, the higher the equilibrium moisture content. The glass transition temperature decreases from 138°C (dry) to 108 to 111°C (for both moisture saturated cases). Moreover, it has been found that moisture absorption reduces the static properties while not modifying the endurance in fatigue tests.

Fatigue behaviour of biocomposites

“…Composite materials may fi nd applications also as bridges, i.e. In fact, it is well known that the presence of moisture, or direct immersion in water reduces the fatigue life of epoxy-based composite materials (Zaffaroni et al, 1998). The high cost and time-consuming preparation of current gold bridges has led to the development of relatively inexpensive composite bridges and dentures (Bjork et al, 1986, Miettinen andVallittu, 1997).…”