Synthesis of thermally degradable epoxy adhesives

We have developed a new strategy for the synthesis of epoxide-containing polymers where the pendant reactive groups are connected to the main backbone via thermally labile oxonorbornene groups. The polymers were synthesized by radical 1,4-polymerization of the appropriate bicyclic diene monomer. The produced polymers can be crosslinked in the presence of a diamine and de-crosslinked by thermal treatment at 160 °C, which induces retro-Diels-Alder reaction and cleaves pendant groups from the polymer backbone, as confirmed by differential scanning calorimetry. The potential for the utilization of this polymer as a thermally removable adhesive was demonstrated by a simple adhesion test. This method provides access to thermally cleavable epoxy networks that can be quickly and irreversibly disintegrated into nonvolatile components upon heating to a specified temperature.