明胶及其与铬(Ⅲ)配合物作用的Zeta电位研究

Zeta Potential of Gelatin and Cr(Ⅲ)Complex Compound

用激光粒度Zeta电位仪能较好地测定明胶胶粒的等电点,及明胶胶粒与铬配合物的作用,研究表明:温度的升高,明胶胶粒表面的负电荷增多,表面的COO^-量增加,从而促进铬鞣剂络合物与皮胶原蛋白的结合;明胶胶粒与硫酸铬作用使明胶表面电荷均为正值,作用时间越长,Zeta电位增加越快,说明硫酸铬主要是阳铬配合物;不浸酸铬鞣剂与明胶胶粒作用时,明胶胶粒的Zeta电位由负向正转变,说明不浸酸铬鞣剂在反应初期是一个较好的阴铬配合物,在与明胶结合的过程中,使明胶胶粒表面的电荷逐渐发生变化。这对于研究不浸酸鞣制机理有重要指导意义。

The Zeta potential of gelatin at different pH and temperature was investigated by Laser Sizer. Results show that the higher the pH value of gelatin solution, the lower its Zeta potential, and that the change of temperature may influence the dissociation and conformation of gelatin because the Zeta potential is much more negative in higher temperature. The variation of Zeta potential of gelatin reacting with chrome sulfate and chrome tanning agent respectively at different conditions were studied. Results indicate that the Zeta potential is positive at the beginning and increases gradually when gelatin reacts with chrome sulfate. However, when gelatin reacts with the chrome tanning agent, that is electronegative at beginning of reaction, its Zeta potential changes from negative value into positive and increases gradually. It is of great importance to study mechanism of chrome tanning .