CAJ | 학술논문

在动态应变条件下,SiO2/CPEG200(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ωc≈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们指数关系.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.
재동태응변조건하,SiO2/CPEG200(취을이순,평균분자량위200)분산체계출현료전절증주현상.전절류변실험표명,재량충정황하도출현료전절증주:일충시재불동적항정빈솔하응변소묘,재림계응력γc출현적전절증주;령일충시항정적응변(γ0=500％)조건하빈솔소묘,재림계빈솔ωc≈10 rad·s-1출현적전절증주.재불동적항정빈솔응변소묘조건하,실험연구료저능모량(G′)화모능모량(G″)여응변적관계,동시초보탐토료응변여불동항정빈솔적함수관계.재선성점탄성구역내,G′화G″만족G″∝ω0.57화G″∝ω0.7문지수관계.재항정적응변조건하,발현모량화복수점도여소묘빈솔구유강렬적의뢰관계,저사현상가이정성지통과"입자족"이론래해석."입자족"이론인위저충전절증주적발생시유우형성료아은정、류동소도치적"입자족",사득점도상승.
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 occurred at critical strain amplitude γc and different constant frequencies,and the second occurred at critical frequency and constant strainamplitude γo=500%.For the fast,the relationships ofboth of the moduli(G'and G″)versus strain amplitude were investigated.The strain amplitude as a function of difierent constant frequencies Was observed.In the linear viscoelastic region,the storage(G′)and the loss((G″)moduli depended strongly on frequency with the power-law:G′∝ ω0.57,G″∝0.7.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.