The super-fast synthesis of high-strength epoxy adhesives by UV-initiated frontal polymerization at room temperature

The synthesis and processing of most polymer adhesives rely on energy-inefficient and environmentally burdensome manufacturing approaches. In this paper, a novel synthesis strategy, UV-initiated frontal polymerization (FP) for the fast synthesis of high-strength, self-propagating epoxy adhesives at room temperature, was presented, in which the self-propagating rate reached 71.4 mm min⁻¹. CuCl₂ was used as a catalyst to decrease the onset temperature of polymerization and ensure sufficient polymerization on the surface of the material to be bonded. Mild steel, glass, ceramic, wood, PMAA, and concrete were successfully bonded within several minutes at room temperature. In the same material system, the adhesive strength with the FP curing approach was greater than that of thermal curing, and the former had a better pore structure, as determined by MIP analysis. This paper provides a promising idea for the in-situ fast synthesis of high-strength epoxy adhesives at room temperature.