Thermoreversible Polymeric Nanocomposites

Abstract

Polymeric nanocomposites are widely used in applications such as structural materials, electronics , energy, and biomedical as they synergistically combine the desired properties of the filler and the polymer. The emergent properties can be designed and tuned based not only on the choice of filler and polymer but also on the type of bond and interface created between the two components. When the bond between the two is covalent, the nanocomposites have superior mechanical characteristics. When this covalent bond is reversible, a combination of high impact resistance and high tensile strength is achieved. A well-known approach to achieve these reversible covalent bonds is via the Diels-Alder reaction between a diene and a dienophile. At elevated temperatures, the retro Diels-Alder reaction is dominant resulting in bond cleavage. This chapter reviews the different strategies involving Diels-Alder reactions at the polymer-filler interface. Various fillers have been researched including silica, carbon nanotubes, and graphene, which impart different mechanical and conductive properties to the nanocomposite. A variety of polymer matrices have been reported by various researchers and are summarized here. The choice of diene and dienophile influences the rate of reversible reaction and thus the final properties as will be discussed.