Provided herein is a composition for use as a thermal interface material in a heat-generating device. The composition comprises a first part and a second part, the first part comprising polyisobutylene, a reactive diluent mixture, a catalyst, and one or more thermally conductive fillers, and the second part comprising polyisobutylene, the reactive diluent mixture, a silicone based cross-linker, an inhibitor and one or more thermally conductive fillers.