延展型表面活性剂降低界面张力的机理研究

Study on the Mechanism of the Novel Extended Surfactants on Reducing the Interfacial Tensions

为了研究新型延展型表面活性剂的构效关系和其降低油水界面张力的机理,采用旋转滴界面张力仪测定了在一定质量浓度的13-P系列(I-C_(13)(PO)_(x)S,x=5、10、15、20)与不同质量分数NaCl和正己烷(n-C6)到正十四烷(n-C14)条件下的等效烷烃数最小值(nmin)。结果表明,在高PO数(x=15、20)时,n_(min)随着NaCl质量分数的升高而增大;在低PO数(x=5、10)时,n_(min)随着NaCl质量分数的升高而减小。由此可以看出,在亲水亲油平衡效应和亲水疏水基尺寸匹配效应中,二者共同作用;在低PO数时,亲水疏水基尺寸匹配效应起主导作用;在高PO数时,亲水亲油平衡效应起主导作用。

To investigate the structure-function relationship of novel extended surfactants and the mechanisms of reducing interfacial tensions(IFTs)at oil-water interface,the interfacial tension values of 13-P series 13-P(I-C_(13)(PO)_(x)S,x=5,10,15,20)with different concentrations of NaCl and n-hexane to n-tetradecane at fixed concentration were measured by rotary drop interfacial tension meter.The result indicates that at higher numbers of PO(x=15,20),the nmin values become higher with increasing concentration of NaCl.At lower numbers of PO(x=5,10),the nmin values become lower with increasing concentration of NaCl.It reflects two mechanisms on reducing IFTs:Hydrophilic lipophilic equilibrium effect and hydrophilic hydrophobic group in size matching effect,both of which work together,and the size matching plays a crucial role at lower numbers of PO and HLB dominates at higher numbers of PO.