Degradable epoxy coatings by photoinitiated cationic copolymerization of bisepoxide with ε-caprolactone

Thermal and hydrolytical degradable epoxy coatings based on bis-phenol-A-diglycidyl ether (DGEBA) and epsilon-caprolactone (CL) were prepared by photoinitiated cationic polymerization using triphenylsulfonium hexafluoroantimonate (Ph3S+SbF6-) as photoinitiator. The photopolymerization kinetics were followed by real-time FT-IR analysis. The effect CL concentration on the rate of polymerization was demonstrated. Mechanical properties of the resulting networks were studied by dynamic mechanical thermal analysis (DMTA). Thermal and hydrolytical degradation investigations were also performed. Higher degradability of the cured films with the increasing content of CL in the formulation suggests that UV cured coatings obtained this way can potentially be used as reworkable thermosets. (C) 2009 Elsevier Ltd. All rights reserved.