物理化学学报 >> 2008, Vol. 24 >> Issue (03): 433-436.doi: 10.3866/PKU.WHXB20080314

研究论文 上一篇    下一篇

SiO2/PEG分散体系动态剪切流变行为

杨海林; 阮建明; 伍秋美; 周忠诚; 邹俭鹏   

  1. 中南大学粉末冶金国家重点实验室, 长沙 410083
  • 收稿日期:2007-09-10 修回日期:2007-12-17 发布日期:2008-03-10
  • 通讯作者: 阮建明 E-mail:jianming@mail.csu.edu.cn

Rheological Behaviors of SiO2/PEG Suspension under Dynamic Shear

YANG Hai-Lin; RUAN Jian-Ming; WU Qiu-Mei; ZHOU Zhong-Cheng; ZOU Jian-Peng   

  1. State Key Laboratory of Power Metallurgy, Central South University, Changsha 410083, P. R. China
  • Received:2007-09-10 Revised:2007-12-17 Published:2008-03-10
  • Contact: RUAN Jian-Ming E-mail:jianming@mail.csu.edu.cn

摘要: 在动态应变条件下, SiO2/PEG200(聚乙二醇, 平均分子量为200)分散体系出现了剪切增稠现象. 剪切流变实验表明, 在两种情况下都出现了剪切增稠: 一种是在不同的恒定频率下应变扫描, 在临界应力γc出现的剪切增稠; 另一种是恒定的应变(γ0=500%)条件下频率扫描, 在临界频率棕c抑10 rad·s-1出现的剪切增稠. 在不同的恒定频率应变扫描条件下, 实验研究了储能模量(G’)和耗能模量(G’’)与应变的关系, 同时初步探讨了应变与不同恒定频率的函数关系. 在线性粘弹性区域内, G’和G’’满足G’∝ω0.57和G’’∝ω0.7指数关系. 在恒定的应变条件下, 发现模量和复数粘度与扫描频率具有强烈的依赖关系, 这些现象可以定性地通过“粒子簇”理论来解释.“粒子簇”理论认为这种剪切增稠的发生是由于形成了亚稳定、流动所导致的“粒子簇”, 使得粘度上升.

关键词: 雾化二氧化硅分散体系, 剪切增稠, 储能模量, 耗能模量, 频率

Abstract: Fumed silica suspensions in polyethylene glycol (PEG200) exhibited shear-thickening behavior under dynamic oscillatory strain amplitude. Two regimes of shear-thickening behavior were obtained: the first occured at critical strain amplitude γc and different constant frequencies, and the second occured at critical frequency and constant strain amplitude γ0=500%. For the first, the relationships of both of the moduli (G’ and G’’) versus strain amplitude were investigated. The strain amplitude as a function of different constant frequencies was observed. In the linear viscoelastic region, the storage (G’) and the loss (G’’)moduli depended stronglyon frequencywith the power-law: G’∝ω0.57, G’’∝ω0.7. In the second regime, the moduli (G’ and G’’) and complex viscosity η* showed strong dependence on frequency. The behaviors could be qualitatively explained using the cluster theory, which attributed the phenomena to the formation of metastable, flow induced clusters.

Key words: Fumed silica suspensions, Shear-thickening, Storage modulus, Loss modulus, Frequency

MSC2000: 

  • O648