聚合物动态流变研究中惯性力项对熔体粘性行为的影响

针对忽略和不忽略惯性力项对熔体粘性行为的影响2种情况,分别推导出振动场中流经毛细管的聚合物熔体剪切应力、剪切速率和表观粘度的计算公式.研究结果表明,当不忽略惯性力项的影响时,这3个参数与毛细管几何尺寸、毛细管体积流量的脉动、毛细管压力降的脉动、应力和应变相位差以及聚合物材料特性等因素显著有关,使得在相同的振动力场中,熔体剪切应力、剪切速率的计算结果比忽略惯性力项时的结果小,而熔体表现粘度的计算结果比忽略惯性力项的时结果大;不忽略惯性力项影响所得到的计算结果更客观地反映了聚合物的振动剪切流变行为.

Effect of the inertia item on viscous behavior of polymer melt during dynamical process

The process of polymer melt dynamically extruding through capillary was analyzed theoretically. The characterization equations of shear stress, shear rate and apparent viscosity of viscous behaviors of polymer melt under the vibration force field were derived with and without the consideration of the inertia item respectively. Compared with the equations without consideration of the inertia item, equations with consideration of the inertia item include the effects of capillary geometrical parameters, capillary pulsant volume flow rate, capillary pulsant pressure drop, phase difference, and material characters on viscous behavior of polymer melt, which cause the calculated shear stress and shear rate is smaller, and the apparent viscosity is larger. It can be concluded that the calculation results with consideration of the inertia item are more reasonable.