Analysis of Chemical Structures of Isocyanurate-Oxazolidone Resins by infrared Absorption Spectroscopy

Isocyanurate-oxazolidone resins were prepared from 2, 4-tolylene diisocyanate (TDI) and 2, 2-bis [p- (2, 3-epoxypropyloxy) phenyl] propane (BPAGE) using N-methylmorpholine as a catalyst. Model polymers containing isocyanurate, oxazolidone, and uretidindione rings were prepared from TDI, diphenylmethane diisocyanate (MDI), triphenyl isocyanurate and BPAGE in order to form calibration curves for infrared spectrum. Composition of hetero rings in the cured product varied with curing temperature, time, and compound ratio. Isocyanate groups changed mainly to isocynanurate rings with ca. 20 mol% of the groups becoming oxazolidone rings. Product contents of uretidindione rings were less than 6mol%. Reaction routes were analyzed from conversion ratios. Variations in the bending strength of the resins made from modified MDI and BPAGE are discussed from product contents of hetero rings.