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Durability and failure analyses of a silane treated α‐Al 2 O 3 /polyethylene joint in wet environment
Author(s) -
Kaul A.,
Sung N. H.,
Chin I.,
Sung C. S. P.
Publication year - 1984
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760240708
Subject(s) - materials science , dehydration , polyethylene , triethoxysilane , durability , composite material , joint (building) , cross linked polyethylene , silane , diffusion , chemistry , structural engineering , biochemistry , physics , engineering , thermodynamics
Abstract The durability of the joints, consisting of α‐Al 2 O 3 primed with γ‐aminopropyl triethoxysilane (γ‐APS) and polyethylene (PE), in wet environment is investigated as a function of the γ‐APS thickness, dehydration of γ‐APS prior to joint formation and redrying the joint after a certain exposure. The joint strength measured by 180°s peel is found to decrease with exposure time in wet environment more rapidly in water than in 100 percent RH. With exposure time, the debonded area increases from the edges toward the central area of the joint. Relatively thin γ‐APS treatments on α‐Al 2 O 3 appear to provide a more durable joint than thicker γ‐APS treatments resulting in an optimal thickness in the range of 0.3 ∼ 1 percent γ‐APS concentration level. Dehydration of γ‐APS leads to more durable joints with an optimal condition found between 1 ∼ 2 days of dehydration at 100°C in vacuum. Regardless of the γ‐APS thickness and dehydration history, the failure in the de‐bonded area seems to occur by the hydrolysis of γ‐APS near the α‐Al 2 O 3 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 central bonded areas, the strength is mostly recovered, characterized by cohesive failure of polyethylene. Diffusion of water in γ‐APS near the α‐Al 2 O 3 side rather than the PE side can explain at least qualitatively most of the observed trends. The effects of γ‐APS thickness and dehydration on the durability in wet environments are compared with those on adhesion promotion in dry environments as well as on their respective failure mode.