Photo cross-linking of some unsaturated poly ether urethane

Abstract

Different unsaturated polyether urethanes have been prepared either by the reaction of methacrylic epoxide copolymers having different methacrylate moiety, with phenylisocyanate or by the reaction of bisphenol (A) of epichlorohydren (Araladite) with methacrylic acid followed by the addition of toluene diisocyanate. The composition of such unsaturated polyether urethane were determined quantitatively by 1H-NMR spectroscopy. The ultrasonic pulse echo technique was used in the range of frequencies between 2 and 8 MHz and temperatures between 240 and 360 K to detect the secondary relaxation both in the presence of a photoinitiator before and after cross-linking by using ultraviolet irradiation. The apparent activation energies for such relaxation were calculated and interpreted according to the flexibility of these polymers. Differential thermal analysis (DTA) and (TG) thermograms as well as IR spectroscopy were also measured and confirmed the formation of cross-linked polyether urethane.