界面张力弛豫法研究不同结构破乳剂油水界面扩张粘弹性

Influences of Demulsifiers with Different Structures on Dilational Properties of Decane-Water Interface by Interfacial Tension Relaxation Methods

采用界面张力弛豫法研究了支链破乳剂AE121和直链破乳剂SP169在正癸烷-水界面上的扩张粘弹性质,并与小幅周期振荡法获得的结果进行了比较.阐述了两种破乳剂的扩张模量随扩张频率和破乳剂浓度的变化规律.研究发现,在低频率处,两种破乳剂的扩张模量均接近于零;在中间频率范围内,扩张模量随扩张频率的增加而增大;在高频率处,扩张模量的幅度接近于极限扩张弹性.在中间频率范围内,扩张模量随破乳剂浓度增大,在接近临界胶束浓度处出现一个极大值;同时还发现,界面上和界面附近的微观弛豫过程的数目随破乳剂浓度增加而增大,其贡献也呈规律性变化.

The dilational viscoelasticity properties of decane-water interface containing two demulsifiers with straight chain (SP169, octadecanol polyoxypropylene-polyoxyethylene ether) and branch chain (AE121, tetraethylenehexamine polyoxypropylene-polyoxyethylene ether) respectively were investigated by interfacial tension relaxation method. The dependence of dilational modulus on dilational frequency was expounded. Our results show that when the dilational frequency is lower, the dilational modulus of the two demulsifiers approches zero; the dilational modulus of the two demulsifiers increases when the dilational frequency becoms higher in the range of medial frequency; and when the dilational frequency is much higher, the dilational modulus of the two demulsifiers reaches to a limiting dilational viscoelasticity. It is also shown that dilational modulus of the two demulsifiers approaches a maximum value near the critical micelle concentration. Along with the increase of demulsifier concentration, the number of relaxation processes gradually increases and the contribution of them also changes regularly.