Encapsulated Imidazole Microspheres for Rapid Curing and Storage Stability of Powder Coatings

ABSTRACT A block copolymer prepared from polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) by atom transfer radical polymerization (PEG‐ b ‐PVP) is used to encapsulate 2‐phenylimidazole (2PZ). The resulting core–shell curing accelerator (denoted as 2PZ@PEG‐b‐PVP) experiences shell rupture at 115°C–120°C, thus releasing 2PZ and achieving the rapid curing of a representative epoxy resin (E‐12). Based on the engineering application performances of 2PZ@PEG‐ b ‐PVP–based powder epoxy coatings, the optimal particle size and coating thickness are determined as ~8.0 and ~2.7 μm, respectively. The optimal powder coating system, which efficiently withstands mechanical stress and preserves its shell integrity during powder processing, can be cured in 5 min at 120°C and stably stored at 50°C for 6 months.