Synthesis and kinetic studies of UV-curable urethane-acrylates

The UV-curable urethane-acrylates based on 2-hydroxyethyl methacrylate (HEMA)-terminated polyurethane (PU) for lithographic and coating applications are investigated in this study. Series of PU prepolymers were made from 4,4-diphenyl methane diisocyanate (MDI), poly(propylene oxide) glycol (PPG 400), poly(butylene adipate)glycol (PBA 500), or poly(tetramethylene oxide) glycol (PTMO 1000) and are terminated with HEMA. The 2,2-azobisisobutyronitrile (AIBN) was used as a UV-initiator under air atmosphere. The curing kinetics of HEMA-terminated PU film were studied. The curing analysis, using FTIR and reaction kinetics, indicate the reaction rate equation correlates well with the film thickness [T], initiator concentration [I], unreacted double bond concentration [C = C], and exposed energy [E] of the reaction system. The kinetic rate equation for the UV-curable reaction can be written as (dt)-(d[C=C]) = k[C=C](1)[I](0.5)[E](0.5)[T](-1) (C) 2004 Wiley Periodicals, Inc.