聚丙烯挤出胀大现象的研究毕业论文推荐.doc

湖南工业大学本科生毕业设计（论文） 湖南工业大学本科毕业设计（论文） PAGE 4 本科毕业设计（论文）资料 题 目 名 称： 聚丙烯挤出胀大现象的研究 本科毕业设计（论文） 聚丙烯挤出胀大现象的研究 摘 要 在聚合物的挤出加工过程中，由于熔体具有粘弹性，当挤出物离开口模后，会出现挤出物的截面面积比口模的截面面积大的现象,即挤出胀大现象，又称Barus效应。影响挤出胀大的因素很多,如聚合物熔体的入口与出口流动、口模结构尺寸、聚合物的分子量大小与重均分子量分布、加工温度、熔体挤出时的剪切速率、剪切应力及口模出口处的热耗散等。挤出胀大现象严重影响了制件的形状和尺寸精度,是合理设计挤出模具和控制制品质量所必须考虑的关键因素之一。 本文针对实验室现有的毛细管流变仪和激光测径仪等设备设计了挤出物直径在线测量系统，对聚丙烯通过不同长径比口模的毛细管后的挤出胀大现象做了具体的实验研究，另外对振动力场下的挤出胀大也做了探讨，分析了挤出胀大现象的影响因素，对制品成型加工过程的控制提供了理论指导。 关键词：聚丙烯，挤出胀大，毛细管流变仪，激光测径仪 ABSTRACT In polymer extrusion process, as with visco-elastic melt, when the extrusion die material left after the objects will appear out of the sectional area than the sectional area of the die is large, that is, the phenomenon of extrudate swell , also known as the Barus effect. Extrudate swell of the impact of many factors, such as the polymer melt flow of the entrances and exits, die size, polymer molecular weight distribution and weight average molecular weight, processing temperature, at the time of melt extrusion shear rate, shear shear stress and the exit of the die, such as heat dissipation. Extrudate swell phenomenon has seriously affected parts of the shape and dimensional accuracy, it is reasonable to control the design of extrusion die and the quality of the products must be considered one of the key factors. In this paper, the existing laboratory capillary rheometer and laser measuring diameter instrument, such as equipment design diameter of the extrusion line measurement system, a different aspect ratio of the polypropylene through the capillary die after the extrudate swell phenomenon specific An experimental study, while under vibration force field on the extrudate swell also discussed an analysis of the impact of the phenomenon of extrudate swell factors, the process of forming products provides a theoretical guidance control. Keywords:PP，polymer melt，extrusion molding，extrusion swell 目 录 第1章 绪论 1 1.1 聚合物挤出胀大现象的研究进展 1 1.3 法向应力的研究进展 1 1.3 毛细管流变仪的测量原理和