Thermally removable epoxy adhesives incorporating thermally reversible Diels-Alder adducts

Thermally reversible adhesives are prepared through the reaction of aliphatic diamines and a diepoxy compound containing two Diels-Alder adducts. The diepoxy compound is formed via the Diels-Alder reaction between two epoxy-containing furans and a bismaleimide. The adhesive displays a T-g of -40degreesC and a constant shear modulus up to approximately 90degreesC. At temperatures exceeding 90degreesC the retro Diels-Alder reaction occurs, which leads to a significant loss in modulus. The loss of modulus is reversible with temperature. A thermally reversible adhesive is proposed based upon the loss of modulus at an elevated temperature, i.e., adhesives bonds are easily broken at elevated temperature where the modulus is low.