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Keywords:

  • polyurethanes;
  • resins;
  • synthesis

Abstract

Three kinds of polyfunctional polyols with hydroxyl values of 180–320 mg/g were prepared by the reaction of hydrogenated terpinene–maleic ester type epoxy resin with secondary amines (diethylamine, N-methylethanolamine, and diethanolamine), and the chemical structures were characterized by Fourier transform infrared spectroscopy and NMR spectroscopy. These polyols were used in place of commonly used polyols to prepare two-component polyurethanes when reacted with polyisocyanates. The crosslinking reactions of the polyols with polyisocyanate could be catalyzed by the tertiary amine groups included in the polyols, and the reaction rate was affected by hydrochloric acid and the polarity of the solvents. The mechanical, water-resistance, and chemical-resistance properties of the crosslinked products of the polyols were evaluated by standard tests, and the thermal properties were examined by differential scanning calorimetry and thermogravimetric analysis. The results show that these epoxy–urethane polymers, with glass-transition temperatures (Tg's) in the range −5 to 37°C, had good thermally resistant properties, and the temperatures at 5% weight loss were in the range 235–280°C. All of the polymers formed transparent, strong, flexible films, with good chemical-resistance properties and excellent impact strengths of greater than 50 cm, a flexibility of 0.5 mm, adhesions of 1–2, and pencil hardnesses of HB–2H. The larger OH functionality and OH value of the polyol resulted in higher Tg and pencil hardness values and better alcohol resistance and thermal stability in the crosslinked product of the polyol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009