Abstract
The use of polymers for under-the-hood automobile parts is growing rapidly. During driving, these parts are exposed to a wide range of potentially harmful conditions, including high temperatures and corrosive chemicals. Such exposure conditions can cause changes in a polymer that might affect its long-term performance. The aging of polymers subjected to the environmental conditions existing under the hood of an automobile has not been extensively investigated. In fact, there has been little quantification of the exact conditions experienced by most of the parts used under the hood of automobiles. This study was conducted to determine the physical aging characteristics of glass-fiberreinforced nylon 6,6. This material is widely used in automobile underhood applications. Two specific glass-fiber reinforced nylon 6,6 parts were examined: a radiator header and an oil cap. The program has determined the environmental thermal stresses experienced by these parts during an instrumented driving run. The physical aging behavior of the glass-fiber-reinforced nylon 6,6 parts was investigated under controlled, accelerated laboratory conditions and after actual use in automobiles driven for various distances.