黄原胶在铬离子存在下的成胶反应

GELATION OF XANTHAN GUM IN THE PRESENCE OF CHROMIUM(Ⅲ)

对黄原胶在铬离子存在下的成胶反应进行了实验研究。描述了反应的动力学过程，并考察了温度、铬离子浓度以及剪切速率对反应速度的影响。同时，就黄原胶／铬作为调剖剂的应用作了讨论。

The gelation of xanthan in the presence of Cr(Ⅲ)was investigated by means of viscosity measurement.The kinetics of the gelation was described as first-order reaction.A particular attention was paid to the influences of temperature,Cr(Ⅲ),and shear rate on the gelation.The gelation was more rapid when the temperature increased.The apparent activation energy △Ea was about 145kJ/mol.It was suggested to control the gelation rate,under high temperature condition,by either adding carboxylate(acetate or propionate)to the simple Cr(Ⅲ)solution as crosslinker or replacing the crosslinker by an Na_2Cr_2O_7-reductant system.It was evident that the gelation rate decreased with increasing the shear rate.Moreover,the application in profile modification was discussed.