Abstract: The durability of aqueous polymer isocyanate (API) wood adhesive was studied under accelerated aging process for 1-7 cycles (A1-A7) and hydrothermal aging for 1-7 cycles (H1-H7) by using Fourier transform infrared spectroscopy(FT-IR), thermogravimetric analysis(TGA), and compressive shear strength analysis. FT-IR analysis showed that the untreated API film(S) contained a considerable amount of isocyanate group, whereas the isocyanate groups of API films for A1-A7 disappeared. Absorption peaks of isocyanate group of API films for H1-H3 still existed, but the intensity weakened. The isocyanate groups of API films for H4-H7 also disappeared. TGA analysis showed that thermal stabilities of A1-A4 in the initial stage were superior to those of H1-H4, but they were almost the same in the 5-7 cycles. Under the same weight loss, the API films with accelerated aging process were more stable, and the degradation activation energies of A1-A7 were not exactly the same, namely, the degradation rates were different. However, the activation energies of H1-H7 were almost the same. The compressive shear strengths of glued products treated in the two methods were gradually decreased. The compressive shear strengths of the API films with accelerated aging process for the third cycle was 5.32 MPa and that of sample with hydrothermal aging for the fifth cycle was 6.92MPa. They did not meet the national standards.

Key words: aqueous polymer isocyanate wood adhesive, durability, accelerated aging, hydrothermal aging