HDPE在振动场中挤出成型时的流变行为

利用自行研制的新型液压振动挤出装置研究了高密度聚乙烯（HDPE）在振动场中挤出成型时的流变行为。研究表明，HDPE熔体在振动场中的表观粘度与振动频率、振幅、口模温度和挤出机螺杆转速均有关，随着振动频率的增加，表观粘度先降至最低值，然后回升到一定程度后基本保持不变，但始终低于未施加振动时的表观粘度；振幅越大，振动场对表观粘度的影响就越大；口模温度超过熔点时，振动场对表观粘度的影响有所增大；螺杆转速越大，振动场对表观粘度的影响就越小。

RHEOLOGICAL BEHAVIOR OF HDPE UNDER VIBRATION EXTRUSION MOLDING

The self-made new type of hydraulic vibration extrusion equipment was adopted to study the rheological behavior of high density polyethylene(HDPE) under vibration extrusion molding.The research results showed that the apparent viscosity of HDPE melt was associated with vibration frequency,vibration amplitude,die temperature and rotational speed of extruder screw.With the increase of vibration frequency,the apparent viscosity decreased to the minimum,then it rose to the definite degree and kept invariable basically,yet the apparent viscosity was always lower than that in the condition of no vibration.The bigger the vibration amplitude was,the stronger the influence of vibration field to polymer melt was.The influence of vibration field to apparent viscosity inceased when the die temperature was above the melt point of HDPE.The faster the screw rotational speed was,the feebler the influence of vibration field to polymer melt was.