纤维尺寸对纤维悬浮液屈服应力的影响

Influence of Fiber Size on the Yield Stress of the Fiber Suspension

利用桨式转子流变仪测量并对比分析了4种不同尺寸尼龙纤维悬浮液在相同体积浓度和集聚因子时的屈服应力,以及2种尼龙纤维按不同比例混合后对悬浮液屈服应力的影响。结果表明,体积浓度相同时,形状系数较大的纤维悬浮液的屈服应力也较大,但形状系数对屈服应力与体积浓度的幂率关系中的乘数项系数和指数项系数未表现出规律性影响;屈服应力不能由单一集聚因子的函数来表示,集聚因子相同时,纤维形状系数较小的悬浮液的屈服应力更大;2种尼龙纤维混合后,屈服应力随形状系数较大的纤维在混合纤维悬浮液中体积分数的减小而呈线性递减趋势。

The yield stresses of the suspensions containing different size nylon fibers were measured by the rheometer with the propeller-type rotor at the same fiber volume fraction and crowding number.The yield stresses of the suspensions containing different mixing ratios of two kinds of nylon fiber were also studied.The results showed that the suspension containing the fiber with larger aspect ratio showed higher yield stress at the same volume fraction.But there was no regular relationship between the aspect ratio and the coefficients of power-law equation of the yield stress and the volume fraction.The yield stress could not be expressed by the function only with the crowding number but was inversely proportional to the aspect ratio.So at the same crowding number,the suspension containing the fiber with lower aspect ratio showed higher yield stress.The yield stress of the mixing suspension of two kinds of nylon fiber decreased linearly along with decreasing of the volume fraction of the fiber with lager aspect ratio.