Alcohol-assisted self-healing network polymer based on vicinal tricarbonyl chemistry

Abstract

We developed a network polymer with solvent-assisted self-healing ability based on vicinal tricarbonyl chemistry. A copolymer bearing vicinal tricarbonyl pendant groups was crosslinked with α,ω-alkanediol through the addition reaction between diol and vicinal tricarbonyl. The resulting hemiketal acted as a dynamic crosslink because it could undergo reversible alcohol-alcohol or water-alcohol exchange reaction in an ambient condition. Thermal and mechanical analyses showed that the polymer networks were in the rubbery state at room temperature while they became a viscoelastic liquid at elevated temperature. The mechanical property and the qualitative self-healing ability were found to depend on the crosslinker concentration. The network polymer with lower crosslinker concentration was less stiff and could be autonomously healed at room temperature. Those with higher crosslinker concentration were stiffer and could not be autonomously healed at room temperature. However, addition of the simplest monool, methanol, to the cut surfaces drastically improved the self-healing ability of the latter samples. The self-healing mechanism and the role of added methanol were discussed in terms of both the chemical and physical aspects.