Evaluation of dopamine and dopamine derivatives as additives in epoxy resin for structural adhesive applications

ABSTRACT

Dry and hot/wet lap shear specimens were prepared and tested to evaluate catechol-containing additives in a model epoxy adhesive. We specifically compared adding neutral dopamine, which is capable of being covalently incorporated into the epoxy network, with molecular analogues that contain methyl, methoxy and fluorine rather than hydroxyl groups. We found that catechol was unique among these additives in improving both dry and hot/wet lap shear strength. While neutral dopamine can only be added to relatively low concentrations due to solubility limitations, other catechol-containing polymers and monomers based on maleimide also showed increases in dry and hot/wet lap shear strength upon incorporation. Dynamic mechanical analysis measurements suggested that the differences observed were not likely due to differences in either polymer mechanical properties or polymer topology.

KEYWORDS:

• Dopamine
• lap shear
• adhesive
• adhesive materials
• bioadhesion
• adhesion by chemical bonding

Acknowledgements

This research was funded by the DEVCOM Army Research Laboratory. We would like to acknowledge Dr. Robert E. Jensen and Mr. David Flanagan for helpful advice on lap shear experiments.

Disclosure statement

Some of the authors of this manuscript have a patent on some aspects of the work discussed herein (U.S. Patent 11,066,583).

Supporting information

Pictures of fractured lap shear specimen are provided in the supporting information.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website