Wang Yiyang, Zhang Lu, Sun Taolei, Zhao Sui, Yu Jiayong
Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, No. 3 Datun Road, Beijing 100101, People's Republic of China.
J Colloid Interface Sci. 2004 Feb 1;270(1):163-70. doi: 10.1016/j.jcis.2003.09.046.
The interfacial dilational viscoelastic properties of two demulsifiers with straight chain (SP-169) and branched chain (AE-121) at the oil-water interfaces were investigated by means of the longitudinal waves method and the interfacial tension relaxation method, respectively. The results obtained by the longitudinal waves method showed that the dilational viscous component for AE-121 and SP-169 also passed through a maximum value with increasing concentration. It was found that the maximum value appeared at different demulsifier concentrations during our experiment frequency; and the higher is the dilational frequency, the lower is the concentration. The influences of AE-121 and SP-169 on the dilational viscoelastic properties of the oil-water interface containing surface-active fraction from Iranian crude oil have been measured. The results clearly stated that both demulsifiers could obviously decrease the dilational elasticity of oil-water interface containing surface-active fraction. At low concentration, because of stronger adsorption ability, SP-169 has stronger ability to decreasing the dilational modulus than AE-121. We also found that the dilational modulus of the interface contained surface-active fraction passed through a minimum value with increasing demulsifier concentration for both demulsifiers. This result indicated the dosage of demulsifier had an optimum value. The results obtained by means of interfacial tension relaxation method showed that the slow relaxation processes involve mainly rearrangement in the conformation of the molecules appeared with increasing demulsifier concentration.
分别采用纵波法和界面张力松弛法研究了具有直链结构的破乳剂（SP - 169）和具有支链结构的破乳剂（AE - 121）在油水界面处的界面扩张粘弹性性质。纵波法得到的结果表明，AE - 121和SP - 169的扩张粘性成分也随浓度增加而经过一个最大值。发现在实验频率范围内，最大值出现在不同的破乳剂浓度处；扩张频率越高，浓度越低。测定了AE - 121和SP - 169对含有伊朗原油表面活性成分的油水界面扩张粘弹性性质的影响。结果清楚地表明，两种破乳剂都能明显降低含有表面活性成分的油水界面的扩张弹性。在低浓度时，由于SP - 169的吸附能力更强，其降低扩张模量的能力比AE - 121更强。我们还发现，对于两种破乳剂，含有表面活性成分的界面的扩张模量都随破乳剂浓度增加而经过一个最小值。这一结果表明破乳剂的用量有一个最佳值。界面张力松弛法得到的结果表明，随着破乳剂浓度增加，缓慢松弛过程主要涉及分子构象的重排。
