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Remendable Polymeric Materials Using Reversible Covalent Bonds
DREXEL UNIV PHILADELPHIA PA DEPT OF CHEMICAL AND BIOLOGICAL ENGINEERING
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Materials that can recover mechanical properties following failure offer increased safety and service life. Moreover, successful development of such systems would reduce factors of safety required in design thus reducing weight. Two approaches for healing polymer networks have captured much attention. In one method, polymer networks are made to self-heal by adding particles filled with uncured resin. The resin held within the particles is released upon crack formation and cures to mend the damage. The other mechanism for healing relies on inherent reversibility of bonds found designed into polymer networks. Our approach to design self-healing composites combines advantages of healing via encapsulation and healing via reversible bonds. Incorporation of a healing agent allows for crack healing while maintaining the desirable physical and mechanical properties of the base thermoset. Reversible bonding of the healing agent provides the ability to crack heal cracks multiple times. We report on the development of two healing systems for epoxy-amine thermosets based on the thermoreversible Diels-Alder reaction of furan and maleimide. Both phenomena occur at room temperature and minimal pressure and significant load recovery is possible multiple times in a given location.
APPROVED FOR PUBLIC RELEASE