PEG浓度对锂藻土分散液的再凝胶化及屈服行为的影响  

Effect of Poly(ethylene glycol) Concentration on the Re-entrant Gelation and Yielding Behavior of Aqueous Hectorite Clay Dispersion

作　　者：疏瑞文[1] 孙尉翔[1] 刘新星[1] 童真[1] 

机构地区：[1]华南理工大学材料科学研究所发光材料与器件国家重点实验室,广州510640

出　　处：《高等学校化学学报》2014年第10期2252-2257,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:51173052;21204023);国家'九七三'计划项目(批准号:2012CB821504)资助~~

摘　　要：通过离子电导率和pH考察了锂藻土自身释放的Na+浓度,说明未经透析或离子交换处理的cw=30mg/mL的锂藻土分散液静置老化后形成的软固体是反应置限团簇聚集(RLCA)的胶体凝胶.通过剪切流变方法研究了聚乙二醇(PEG)浓度cp对锂藻土/PEG分散液体系的线性和非线性黏弹性的影响.小幅振荡剪切(SAOS)频率扫描结果表明,随着cp增加,锂藻土发生'RLCA凝胶-黏弹性液体-排空(Depletion)凝胶'转变,可观察到该体系的再凝胶化行为.稳态剪切和大振幅剪切实验结果表明,锂藻土/PEG分散体系的再凝胶化的非线性流变学行为也有体现.The Na＋ concentration released from hectorite clay was evaluated from the conductivity and pH. The results indicated that the soft solid formed by 30 mg/mL aqueous heetorite clay dispersion after aging without dialysis or ion exchange was reaction-limited cluster aggregation （RLCA） colloidal gel. The effect of polyethylene glycol （PEG） concentration cp on the linear and nonlinear viscoelasticity of the hectorite clay/PEG dispersions was investigated by rheology. Small amplitude oscillatory shear（SAOS） frequency sweep indicated that the heetorite clay/PEG gel dispersion experienced a ＂ RLCA colloidal gel-viscoelastic liquid-depletion colloidal gel＂ transition with increasing Cp. The re-entrant gelation was firstly observed in this dispersion. Shear viscosity and dynamic moduli under large amplitude oscillatory shear revealed that the PEG concentration affected similarly on the yielding behavior of the hectorite/PEG dispersion.

关 键 词：锂藻土 聚乙二醇 再凝胶化 屈服行为 小幅振荡剪切 反应置限团簇聚集 

分 类 号：O631[理学—高分子化学]