(251m) Encapsulation of Maleimide-Based Healing Agent and Reversible Diels-Alder Chemistry for Self-Healing and Corrosion Prevention

Encapsulation of Maleimide-Based
Healing Agent and Reversible Diels-Alder Chemistry for Self-Healing and
Corrosion Prevention

Sadella Santos¹, Giuseppe Palmese*¹

¹Department of Chemical & Biological
Engineering, Drexel University, Philadelphia, Pennsylvania, 19104, United
States

ABSTRACT

Protective epoxy coatings for metal substrates are used for wear
resistance and physical protection against environment conditions that may
result in physical or chemical changes, such as corrosion. Previous work done
by Pratama et. al ¹ investigated the use of encapsulated solutions containing
maleimide-based healing agents for self-healing of furan functionalized epoxy
networks through reversible Diels-Alder chemistry. Results from these studies show
that the use of phenyl acetate as a solvent, and the concentration and
structure of maleimide healing agent has an effect on the physical and chemical
bonding across the crack surface.  We used a urea-formaldehyde (UF)
encapsulation technique to create capsules with a diameter of ≤ 300 um,
containing phenyl acetate-maleimide solutions.  This healing system allowed for
multiple healing cycles and increased load recovery. The phenyl acetate-maleimide
healing agent and Diels-Alder reactions can similarly be used in the design of
self-healing polymer systems for coatings. Specific protective epoxy coatings
require a thickness of 30-40 um, thus capsules with an approximate diameter of
≤20um are desired. This can be achieved by increasing shear rate and by
incorporating ultrasonication processing to the UF encapsulation procedure. The
purpose of this work is to study the effect of capsule size on healing
efficiency in thin films that are representative of coatings.

¹Pratama, P. A.,
Sharifi, M., Peterson, A. M., & Palmese, G. R. (2013). Room Temperature
Self-Healing Thermoset Based on the Diels?Alder Reaction. ACS applied materials &
interfaces, 5(23),
12425-12431.