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.
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
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