EFFECTS OF REACTIVE DILUENTS ON MECHANICAL AND PHYSICAL-PROPERTIES OFA UV CURABLE ACRYLATED URETHANE PREPOLYMER

In this study, the dependence of the mechanical properties of a UV cur able acrylated urethane on reactive diluent types and their amounts wa s investigated. The acrylated urethane prepolymer was synthesized from isophorone diisocyanate (IPDI), an aliphatic diisocyanate, and polypr opylene glycol monomethacrylate (PPGMMA) by stepwise addition reaction . UV sensitive mixtures containing N-vinylpyrrolidinone (NVP), thiodie thylene glycol diacrylate (TDGDA) and isobornyl acrylate (IBoA) as rea ctive diluents were irradiated by UV light. An increase in reactive di luent content, either TDGDA or IBoA, caused an increase in tensile str ength and a decrease in elongation values. In contrast, above a certai n concentration a decrease in tensile strength was observed when NVP w as used as reactive diluent. The water absorption capacities of the UV curable acrylated urethane films were observed to depend on type and amount of reactive diluent that was used. Thermooxidative properties o f the films were also improved by incorporation of reactive diluents i nto formulations.