The fracture of epoxy- and elastomer-modified epoxy polymers in bulk and as adhesives
Article first published online: 9 MAR 2003
Copyright © 1975 John Wiley & Sons, Inc.
Journal of Applied Polymer Science
Volume 19, Issue 9, pages 2545–2562, September 1975
How to Cite
Bascom, W. D., Cottington, R. L., Jones, R. L. and Peyser, P. (1975), The fracture of epoxy- and elastomer-modified epoxy polymers in bulk and as adhesives. J. Appl. Polym. Sci., 19: 2545–2562. doi: 10.1002/app.1975.070190917
- Issue published online: 9 MAR 2003
- Article first published online: 9 MAR 2003
- Manuscript Revised: 29 JAN 1975
- Manuscript Received: 16 JUL 1974
The fracture behavior of a piperidine/bisphenol A diglycidyl ether (A) resin has been determined in bulk and as an adhesive using the linear elastic fracture methods developed by Mostovoy1. The effect of adding carboxy-terminated butadiene–acrylonitrile (CTBN) elastomer to resin A was investigated. The opening-mode fracture energy () of resin A was 120 to 150 J/m2, and largely attributable to plastic deformation. Fractographic evidence was obtained for plastic flow at the crack tip during crack initiation. Propagation was unstable due to the rate dependence of the plasticity. There were no significant differences in the bulk and adhesive fracture behavior. Addition of 5–15% CTBN to resin A produced minute elastomer particles which increased to ∼4000J/m2 (at 15%). Further CTBN addition resulted in an elastomer–epoxy blend and a decrease in fracture energy. Fractography again indicated that crack initiation involved plastic deformation but that the elastomer had greatly increased the volume in which the deformation occurred. The adhesive fracture of the elastomer–epoxy was found to be strongly dependent on the crack-tip deformation zone size (ryc) in that was a maximum when bond thickness was equal to 2 ryc. At bond thicknesses less than 2 ryc, there was a restraint on the development of the plastic zone resulting in lower values.