The Effects of Surface Properties of Polyurethane Adhesives on Adhesion Strength of Poplar Veneer

摘要

Inverse gas chromatography (IGC) method was used to determine surface properties of a series of polyurethane adhesives cured with water A1, A2, A3 and A4, their percentages of isocyanate group were 5.3%, 7.0%, 13.0% and 19.6%,respectively. Four n-alkanes C6, C7, C8 and C9 were chosen as non-polar probes to characterize the dispersive component of surface free energy. Acetone, tetrahydrofuran and ethyl acetate were chosen as polar probes to detect the Lewis acid-base parameters. The trends of dispersive component of surface free energy and Lewis acid-base parameters of each adhesive were shown in this paper also. The surface of each adhesive is amphoteric, but predominantly Lewis basic. Adhesive strength of adhesives with poplar was tested. The results showed that the adhesion strength of adhesives increased with increment of the value of Kb/Ka of adhesives from A1 to A4.