Durability and Failure Analyses of a Silane Treated Alpha-A1203/Polyethylene Joint in Wet Environment.
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MATERIALS SCIENCE AND ENGINEERING
Pagination or Media Count:
Investigated is the durability of the joints Alpha-A1203Gamma-APSPE in wet environment as a function of the gamma-APS thickness, dehydration of gamma-APS prior to joint formation and redrying the joint after a certain exposure. The joint strength measured by peel strength is found to decrease with exposure time in wet environment more rapidly in water than in 100 RH. With exposure time, the debonded area increases from the edges toward the central area of the joint. Relatively thin gamma-APS treatment on alpha-A1203 appear to provide more durable joint than thicker gamma-APS treatment resulting in an optimal thickness in the range of 0.3 approx.1 gamma-APS concentration level. Dehydration of gamma-APS lead to more durable joint with an optimal condition found between 1 approx. 2 days of dehydration at 100 deg C in vacuum. Regardless of the gamma-APS thickness and dehydration history, the failure in debonded area seems to occur by the hydrolysis of gamma-APS near alpha-A1203 side and by the deformation of polyethylene cohesive failure in the peeled area, as characterized by SEM and ESCA. The debonded area in the dried joint recovers little strength but in the bonded central areas, the strength is largely recovered, characterized ny the extensive deformation of polyethylene. Diffusion of water in gamma-APS near alpha-A1203 side rather than PE side can explain at least qualitatively most of the observed trends. Comparisons are made for the effects of gamma-APS thickness and dehydration on the durability in wet environment and adhesion promotion in dry environment as well as on their respective failure mode.
- Adhesives, Seals and Binders