The shear thinning behavior of non-colloidal suspensions is investigated experimentally with emphasis on the effect of surface roughness of suspending particles. The first shear thinning at a low shear-rate is observed, which originates from particle–particle interaction, and the second shear thinning at a high shear rate is also reported as the polymeric solvent shear thins. Due to the decrease of the size of particle clusters, the viscosity of suspensions decreases in the first shear thinning regime. The surface asperities on rough particles hinders the lubricative interaction between close-contact particles suppressing the growth of clusters, and therefore, the first shear thinning behavior weakens. The shielding of the lubricative interaction also prevents the local shear rate enhancement, corresponding to the suppressions second shear thinning and the rising of a second-order first normal stress difference from the polymeric solvent. A theoretical model describing the first shear thinning behavior of non-colloidal suspension is developed, and the predications agree well with experimental data. The roughness effect on dynamic rheological behavior is also investigated.

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表面粗糙度对非胶体悬浮液剪切稀化的影响

实验研究了非胶体悬浮液的剪切稀化行为，重点是悬浮颗粒表面粗糙度的影响。观察到在低剪切速率下的第一次剪切稀化，这是由于颗粒间的相互作用引起的，在高剪切速率下的第二次剪切稀化也被报道为聚合物溶剂剪切稀化。由于颗粒簇的尺寸减小，在第一剪切稀化方案中悬浮液的粘度降低。粗糙颗粒上的表面凹凸阻碍了紧密接触颗粒之间的润滑相互作用，从而抑制了团簇的生长，因此，第一剪切稀化行为减弱了。润滑相互作用的屏蔽还阻止了局部剪切速率的提高，对应于抑制第二剪切变薄和来自聚合物溶剂的第二阶第一法向应力差的升高。建立了描述非胶体悬浮液第一剪切稀化行为的理论模型，其预测结果与实验数据吻合良好。还研究了粗糙度对动态流变行为的影响。