Abstract:The interaction between the gelatin and the binary quaternary ammoniums, which was prepared from 1,2-ethanediamine and 1,4-butanediamine, was studied. The effect of these two compounds on the viscosity of gelatin solution was studied under various conditions including gelatin concentration, pH value, temperature, etc. The results show that with the addition of the binary quaternary ammoniums, the viscosity of dilute gelatin solution (1%) decreases, while that of the concentrated gelatin solution (5%~7%) increases. This phenomenon implies that the crosslinking occurs inside the random coil of gelatin in dilute solution, and between two neighboring gelatin molecules in concentrated solution. This crosslinking interaction is remarkable under 30 ℃ and alkalescent (pH=8). After being dipped with binary quaternary ammoniums, the dried gelatin shows relative small swelling ratio and high glass transition temperature, which indicates that the crosslinking improves the water resistance and the thermal stability of the dried gelatin.