AbstractSyntheses of several photocurable resins and their properties before and after photocuring are investigated. Unsaturated oligoester acrylourethanes (IIIa–IIId) are prepared by addition reaction between four types of hydroxy‐terminate unsaturated oligoesters (Ia–Id) and intermediate of adduct II. The former is prepared by addition‐condensation reaction of glycols and maleic anhydride, while the latter is prepared from 2,4‐TDI and equivalent HEMA by addition reaction in the presence of stannous octoate with THF as solvent. From the decrease of NCOs characteristic absorption peak at 2250 cm−1of IR spectrum, the conversions of the reaction of 2,4‐TDI with HEMA and hydroxy‐terminated unsaturated oligoesters were calculated. The unsaturated photocurable resins are compared with saturated oligomers (obtained by replacing maleic anhydride with succinic anhydride) with regard to curing rates and mechanical properties. Properties of pure oligomers are determined both before and after hardening. If added with reactive monomers, the oligomers thus cured are found to possess better properties than otherwise. Among the monomers, HEMA proves to be especially helpful in the increase of mechanical properties. Above all, combined use of IIIb oligomer and HEMA serves the best purpose fo
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