PREPARATION OF RIGID POLYURETHANE FOAMS CATALYZED BY METAL-ALKANOLAMINE COMPLEXES

In this research, we developed new catalysts which have no odor and have less amount of volatile organic compound (VOC) in the rigid polyurethane foam preparation process. The catalysts were synthesized from the reaction between metal acetate and alkanolamine to give metal-alkanolamine complexes. These complexes were used as catalysts in the preparation of rigid polyurethane foams. Metal acetates employed were copper acetate and zinc acetate. Alkanolamine employed were ethanolamine and diethanolamine. UV-Vis spectroscopy, FTIR spectroscopy and mass spectrometry were used to characterize the metal-alkanolamine complexes. Rigid polyurethane foams were prepared by using metal-alkanolamine complexes as catalysts. The reaction times of the foam formation, namely cream time, gel time, tack-free time and rise time were studied. The completion of polymerization reaction was studied by using FTIR spectroscopy and isocyanate conversion was calculated. The results were compared with those from dimethylcyclohexylamine, which is a commercial catalyst used in the preparation of rigid polyurethane foam. From the result, the copper-ethanolamine complex rendered comparable catalytic activity to dimethylcyclohexylamine. Density and compressive strength of polyurethane foam catalyzed by copper-ethanolamine complex was 43 kg/m3 and 362 kPa, respectively.