表面活性剂对海藻酸钠稀水溶液剪切粘度的影响

Effect of Surfactants on the Shear Viscosity of Dilute Aqueous Solutions of Sodium Alginate

通过粘度法考察了不同pH值时,阴离子聚电解质海藻酸钠(NaAlg)与阴离子表面活性剂十二烷基硫酸钠(SDS)、阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)、非离子表面活性剂辛基酚聚氧乙烯醚(TritonX-100)以及它们的复配体系的相互作用.研究表明,在酸性条件下,SDS和TritonX-100与NaAlg之间主要是疏水作用,随着表面活性剂浓度的增加,体系粘度下降直到基本不变,CTAB与NaAlg主要发生静电作用和疏水作用,体系粘度随CTAB浓度的增加呈现先上升后下降的趋势.在实验条件下,TritonX-100浓度为0.05mmol·L-1时,SDS的加入,使得NaAlg/TritonX-100体系的零剪切粘度下降,而CTAB的加入,在pH=3.0和5.0时,NaAlg/TritonX-100体系的零剪切粘度出现上升,在pH=6.4时,该体系零剪切粘度下降.

Interactions between the anionic polyelectrolyte sodium alginate （NaAlg） and the anionic surfactant sodium dodecyl sulfate （SDS）,the cationic surfactant cetyltrimethylammonium bromide （CTAB）,non-ionic surfactants octylphenol polyethoxylates （TritonX-100） as well as their compounded system were investigated by viscosity measurement techniques at different pH values in dilute solution. A hydrophobic interaction was observed in NaAlg/ SDS and NaAlg/TritonX-100 aqueous solutions. By increasing the surfactant concentration the zero-shear viscosity initially decreased and then remained almost unchanged. However,the strong association between NaAlg and CTAB was affected by an electrostatic attraction and also a hydrophobic interaction. In acidic solution,the zero-shear viscosity initially increased and then decreased as the CTAB concentration increased. At a TritonX-100 concentration of 0.05 mmol·L-1,the zero-shear viscosity decreased upon addition of SDS for the NaAlg/TritonX-100 system under laboratory conditions. Upon addition of CTAB,the zero shear viscosity of NaAlg/TritonX-100 system increased at pH 3.0 and 5.0 but decreased at pH 6.4.