疏水链对双子表面活性剂性能的影响

Study on the Effect of Hydrophobic Chain on Gemini Surfactants

关键词:  双子表面活性剂  表面活性  界面活性  乳化性能  泡沫性能  热重分析

Key words:  Gemini surfactant  surface activity  interfacial activity  emulsifying capability  foam property  thermogravity analysis

摘要:

以壬基酚或对特辛基酚和二溴丁烷为原料合成了含不同支化度疏水链的磺酸盐型双子表面活性剂R2C4和D2C4(C为联结基中亚甲基,R为疏水基壬基,D为疏水基仲辛基),研究了其水溶液的表面活性、界面活性、乳化性能、泡沫性能及热稳定性,讨论了疏水链的支化程度对其性能的影响。试验发现磺酸盐型双子表面活性剂具有较高的表面活性,其中R2C4的临界胶束浓度(CMC)较低,而D2C4的临界表面张力较低,R2C4具有比D2C4更优的界面活性;对同一有机相,R2C4的乳化性能要优于D2C4;R2C4的起泡性及泡沫稳定性优于D2C4;R2C4和D2C4的初始分解温度分别为293℃和322℃,即二者都具有较好的热稳定性,高支化度的疏水链提高了表面活性剂的热稳定性。

Abstract:

Sulfonate Gemini surfactants R2C1 and D2C4 (C represents methylene in spacer groups, R represents hydrophobic group nonyl, D represents hydrophobic group sec-octyl phenol)with different hydrophobic groups were synthesized using nonylphenol or octylphenol and 1, 4-dibromobutane. Surface activity, interracial activity, emulsifying capability, foam property and thermal stability of the aqueous solution were studied, and influence of hydrophobic groups to performance was discussed. It is found that sulfonate Gemini surfactants have better surface activity, the cmc of R2C4 is lower and the critical surface tension of D2C4 is lower, R2C4 has better interfacial activity than D2C4 ; the emulsifying capability of R2C4 is superior to D2C4 ; the foaming tendency and foam stability of R2C4 gain the advantage over D2C4; the initial decomposition temperature of R2C4 and D2C4 can reach 293℃ and 322℃ respectively, so both have better thermal stability. The high degree of hydropho- bic chains improves the thermal stability of Gemini surfactants.