Environmental Failure of Adhesive Bonding in Composites.
Abstract
A recently developed fracture mechanics test (the A-S test), which involves pressurisation of an enclosed circular flaw, has been used to investigate the adhesion of two epoxy resins (Shell Epikote 828 and 3 M's SP 250) to glass. Specimens were tested after various times of immersion in water at 80 C and the adhesive failure energy theta determined. The effects of adding silane coupling agents to the epoxy resin and the influence of water pH were particularly studied. The theory of generalized fracture mechanics is used to derive, from theta, an intrinsic failure failure energy theta sub 0 which is the energy to break unit area of interatomic bonds across the interface. The decrease of theta sub 0 with time follows first order reaction kinetics, with a rate constant controlled by the type and concentration of coupling agent as well as by the pH of the aqueous environment. The results are interpreted in terms of the chemical hydrolysis of interfacial bonds. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1981
- Accession Number
- ADA107538
Entities
People
- C. Vlachos
- E. H. Andrews
- H. A. Majid
- Ho Ping Sheng
Organizations
- Queen Mary University of London