对三种不同类型高密度聚乙烯（HDPE）进行高压毛细管挤出,均发现特殊的温度窗口效应,线性均聚5000S在v=8mm/min时的温度窗口为145℃~150℃;己烯共聚HXM TR-571在v=1mm/min时的窗口为150℃~153℃;双峰型GC100S在v=5mm/min的窗口为143℃~145℃,温度窗口内挤出压力骤降至最小值,挤出平稳,挤出物表面光滑,避免了压力振荡和变形,窗口与PE的分子量、支化度和柱塞速率有关。效应产生的原因是在温度窗口内发生了PE晶形相转变。不同挤出温度挤出物的差示扫描量热（DSC）分析表明,HXM TR-571和GC100S在窗口温度下挤出物具有较高的结晶温度（Tc）和较低熔点（T（m 2））。
In the paper,three different types of high-density polyethylene（HDPE） had been extruded in the high-pressure capillary.During the extrusion,it was founded that the temperature windows of linear polyethylene 5000S,copolymer HXM TR-571 and bimodal polyethylene GC100S were 145 ℃～150 ℃（piston velocity（v） = 8 mm/min）,150 ℃～153 ℃（v=1 mm/min） and 143 ℃～145 ℃（v=5 mm/min）,respectively.When the pressure of extrusion dropped dramatically to a minimum within temperature window,the extrusion became stable and smooth,avoiding the oscillations and distortions.The temperature window,being in a close relation to molecular weight,degree of branching and v,was the consequence of a phase transformation at the particular temperature within the orifice of the capillary.Differential scanning calorimeters（DSC） thermal analysis of the extrudates under different temperature show that the extrudates of HXM TR-571 and GC100S within the temperature window have higher crystalline temperature（Tc） and lower melting points（T（2）m）.
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