摘要：为了阐明常用于评价无机粉体表面改性效果的粉体活化指数的局限,建立悬浮于水面的球形粒子的静态力学模型,从理论上说明表面有机化的无机粒子悬浮于水面的支撑力的来源,并进一步指出用活化指数评价无机粒子的有机化程度存在的理论缺陷;通过模拟计算阐明水面悬浮球形粒子接触角、浸没深度、支撑力之间的关系,并利用实验对理论分析进行验证。结果表明:表面有机化的无机粒子悬浮于水面的支撑力主要来自于水作用于粒子的表面张力的垂直分量;活化指数的方法不宜用来定量地评价无机粒子的改性效果。

关键词：表面张力；活化指数；静态力学模型；悬浮粒子

Abstract： To clarify the limits of powder activation index often used to evaluate the surface modification effect of inorganic powders, a static mechanical model of ball-shaped particles floating on water surface was proposed. The source of the force keeping inorganic particles surface organized floating on water surface was illustrated in theory. The theoretical limitations of activation index were pointed out. The relationship between contact angle, immersion depth and vertical upward force were investigated through stimulant calculation and theoretical analyses were proved by experiment. The results show that the source of the force which keeps inorganic particles surface organized floating on water surface is the vertical component of surface tension of water acting on the ball-shaped particles floating on water surface. The activation index cannot be used to quantitatively characterize the surface coating effect of inorganic particles. 

Keywords: surface tension; activation index; static mechanical model; suspended particles