熔体流变特性的测定方法

为了测定熔体的流变特性,将普通的旋转粘度仪改造成转速可变的·用其测定了不同粘度的标准油,给出了仪器的重现性误差和试验总误差,试验总误差为测量牛顿流体时所容许的最大偏差·通过分析试验数据,确定试验中容许忽略屈服应力对粘性因子影响的最大误差值·进而,给出了判定熔体是否为非牛顿流体和确定非牛顿流体中是否有屈服应力的方法,其结果为深入研究熔体流变特性奠定了必要的基础·

Measurement of Rheologic Characteristics of Melts

A conventional rotary viscometer was restructured available to variable speeds to measure the rheological characteristics of melts, e.g., the oil viscosities of different standard grades. The reproducibility error of this viscometer and the total error of measurements, i.e., the maximal permissible measuring error of Newtonian fluid in measurement are given. The maximal permissible error caused by neglecting the effect of yield stress on viscous factor was determined through the analysis of measured data. An approach to determine whether a melt is non-Newtonian fluid and whether there is a yield stress in the non-Newtonian fluid was further given. The results mentioned above will provide a necessary basis for further research on the rheologic characteristics of melts.