Effect of UV radiation on some semi-interpenetrating polymer networks based on polyurethane and epoxy resin

The modifications of properties of some semi-interpenetrating polymer networks based on aromatic polyurethane and a crosslinked epoxy resin, during UV irradiation with a mercury lamp (λ > 300 nm), were investigated. Variation of some properties, such as colour, gloss, contact angle, mass variations and water retention were monitored according to the irradiation time. Photochemical reactions that occurred during irradiation were monitored by FT-IR. The results demonstrated that polyurethane-epoxy resin semi-interpenetrating polymer structures showed a higher photo-stability than the polyurethane sample.