作　　者： ; ;

机构地区： 株洲工学院

出　　处： 《高校化学工程学报》 2004年第3期381-384,共4页

摘　　要： 借助流变测量和连续介质理论,不依赖已有的本构关系,对平行叠加正弦振动条件下高分子熔体经毛细管的动态挤出过程进行了理论分析。以低密度聚乙烯(LDPE)为原材料,实验测量LDPE熔体在一定振动频率和振幅下毛细管入口压力、体积流量和挤出胀大的瞬态值,即可得到动态成型过程中高分子熔体剪切应力、剪切速率和表观粘度的变化规律:随振幅和频率的变化,LDPE熔体的表观粘度呈非线性变化趋势;在不同的振幅和频率下动态挤出LDPE熔体,跟稳态挤出时一样,壁面剪切应力与壁面剪切速率也成非线性比例关系。 With a device of adding parallelly a sinusoidal vibration at the flow direction to the flowing polymer melt, an experimental equipment of dynamic rheometer of capillary (DRC) was designed, and the whole process of polymer melt dynamically extruded through capillary was analyzed theoretically. By measuring instantaneous data of capillary entry pressure, volume flux and die swell of LDPE melt under certain frequency and amplitude of vibration, the shear stress at capillary wall, shear rate at capillary wall, and apparent viscosity of polymer melt were obtained. It is found that wall shear stress and wall shear rate of LDPE melt extruded dynamically under various amplitude and frequency exhibits a nonlinear proportional relationship; moreover, the apparent viscosity of melt under various amplitude and frequency of vibration emerges a tendency of nonlinear change; compared with stable state extrusion, after introducing vibrating force field, the apparent viscosity of melt all decreases pronouncedly.

关 键 词： 高分子熔体 动态成型 非线性行为 毛细管

领　　域： [化学工程] [化学工程]