镁铝类水滑石/阳离子淀粉分散体系流变学振荡行为研究  

Rheological Fluctuation Behavior of Suspensions Containing Aluminum Magnesium Hydrotalcite-like Compound and Cationic Starch

作　　者：李燕[1] 毕浩宇[2] 申双龙[1] 

机构地区：[1]长治学院化学系,长治046011 [2]长治医学院生物医学工程系,长治046000

出　　处：《化学学报》2011年第5期565-569,共5页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20273041;20573065);山西省高校科技开发(No.20091038)资助项目

摘　　要：采用稳态剪切和小振幅振荡剪切实验研究了镁铝类水滑石化合物(Mg-Al HTlc)/阳离子淀粉(CS)分散体系(HTlc与CS质量之比R分别为0,0.02,0.05和0.08)的流变学性质.实验结果表明:上述体系在实验pH值(5～11)范围内均为剪切稀释非牛顿流体,其中,Mg-Al HTlc/CS(R=0,0.02和0.05)分散体系的流变曲线符合幂律模型,而Mg-Al HTlc/CS(R=0.08)体系符合Herschel-Bulkley模型.上述体系先于1000 s-1剪切180 s,再于1 s-1(或者3 s-1)低速剪切时均表观出粘度随时间周期变化的振荡现象.振荡现象缘于CS分子结构的周期变化.pH值、剪切速率和HTlc含量的变化可以改变振荡周期(频率)和振幅.低pH值条件下,Mg-Al HTlc/CS(R=0.08)体系先于1000 s-1剪切180 s,再于小振幅振荡剪切(剪切应力0.03 Pa,频率0.5 Hz)时储能模量G′和损耗模量G″也表现出随时间周期变化的振荡现象.The rheological properties of aqueous suspensions containing cationic starch （CS） and positively charged aluminum magnesium hydrotalcite-like compound （Mg-A1 HTIc） were investigated by steady shear and oscillatory shear experiments. In the range of pH tested, all of the suspensions exhibit shear-thinning behavior. The rheological fluctuation behavior was discovered in the suspensions, i.e., the apparent viscosity of the suspensions oscillated with time at a constant low shear rate after pre-shearing. The fluctuation mechanism is proposed in terms of the periodic transformation of CS molecular （chain） conformation. Because pH, interaction between HTlc and CS molecule and shear rate can affect the energy and frequency of transformation of CS molecular conformation, the oscillation amplitude and period can change with pH, HTlc content and shear rate.

关 键 词：类水滑石化合物 阳离子淀粉 分散体系 流变性 振荡 

分 类 号：TQ021.1[化学工程]