Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Limits on Toughening in Structural Adhesives

Published

Author(s)

Donald L. Hunston, H Jianmei, R Raghavan, D Hoffman

Abstract

The addition of a toughener to a thermoset resin, usually an epoxy, can increase the fracture energy by an order of magnitude or more. These materials are two phase systems with small toughener particles in a thermoset matrix. The fracture behavior depends on the constituents, the toughener concentration, and the morphology (particle size distribution). Unfortunately, the inability to alter just one microstructural feature at a time makes it difficult to establish structure-property relationships. The work here uses a new material system that starts with preformed particles so the toughener concentration can be varied without changing the morphology or constituents. The fracture results for this material show that the toughness increases to a maximum at about 15 phr (parts toughener per hundred parts of epoxy by mass) and then decreases gradually as the concentration is increased up to 67 phr. Micrographs of the initiation region on the fracture surface show much less deformation at high toughener concentrations than at 15 phr. This suggests that there is an optimum toughener concentration for achieving maximum energy.
Citation
Adhesion Society

Keywords

acrylic, disperson, epoxy, fracture, morphology, preformed particles, thermoset, toughening

Citation

Hunston, D. , Jianmei, H. , Raghavan, R. and Hoffman, D. (2008), Limits on Toughening in Structural Adhesives, Adhesion Society (Accessed October 11, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created October 16, 2008