PE-UHMW/PE-HD熔融挤出初生丝挤出胀大现象模拟分析

以熔融纺丝过程为研究对象,采用PTT本构模型,运用有限元分析方法,对高密度聚乙烯(PE-HD)改性超高分子量聚乙烯(PE-UHMW)共混物熔融法挤出初生丝的过程进行了数值模拟,对比分析了口模温度和熔体泵转速的变化对挤出过程速度场和剪切速率场分布的影响,探究了影响初生丝挤出胀大现象的因素。研究表明,随着挤出口模温度的升高,初生丝挤出胀大现象明显减弱,挤出胀大比从280℃的1.318降低到310℃的1.264。然而,随着熔体泵转速的增大,初生丝挤出胀大现象显著增强,挤出胀大比由转速为1r/min的1.258增大到5r/min的1.318。

Simulation Analysis of Extrusion Swelling in As-spun Filament of the PE-UHMW/PE-HD Blends Melt Extrusion Process

Taking the melt spinning process as the research object,the PTT constitutive model was used to simulate the pro- cess of extrusion of the as-spun filament by high-density polyethylene (PE-HD) modified ultra high molecular weight polyethylene (PE-UHMW) blend by finite element analysis. The effects of temperature and the speed of melt pump on the velocity field and shear rate field distribution of the extrusion process were compared and analyzed,and the factors affecting the extrusion swell of the as- spun filament were explored. The studies show that as the temperature of extrusion die increases,the extrusion swell of the as-spun filaments is significantly reduced,and the extrusion swell ratio is reduced from 1.318 at 280 ℃ to 1.264 at 310℃. However,as the speed of the melt pump increases,the extrusion swell of the as-spun filaments is significantly increased,and the extrusion swell is increased from 1.258 at 1 r/min to 1.318 at 5 r/min.