The influence of modified VER on PU VER IPN

Purpose - The aim of the paper is to develop a method to block hydroxyl groups of epoxy acrylate (AAEP) in vinyl ester resin (VER) and to study the influence of modified VER on polyurethane (VER) interpenetrating polymer network (PU VER IPN).Design methodology approach - The hydroxyl groups of AAEP in VER were blocked via different methods. Infra-red spectroscopy was adopted to study the influence of the reagents, reaction temperature and feed molar ratio on the blocking effect of hydroxyl groups and the optimised technological parameters were determined. The PU VER IPN and PU modified VER IPN were prepared by simultaneous interpenetrating of VER (mixture of AAEP and butyl methacrylate with the mass ratio of 2 1) or modified VER and synthesised PU in their laboratory. The microstructure, dynamic mechanical properties and mechanical properties of PU VER IPN and PU modified VER IPN were compared.Findings - The results showed that compared to unmodified IPN, because the hydroxyl groups in VER were blocked and no chemical cross-linked structure existed between the two networks, the modified IPN showed dual-continuous microsturcture with larger phase domain sizes between 20 and 50 nm. The effect damping temperature range of modified IPN was broadened and its damping performance was improved. The mechanical strength of modified IPNs decreased and their break elongation increased evidently.Practical implications - The PU modified VER IPN with excellent damping properties can be used in the applications where reduction of vibration and noise is desired.Originality value - The PU modified VER IPN, in which no chemical cross-linked structure existed between the two networks, was novel and its damping performance was improved and excellent.