【作者】 李莹；

【导师】 俞炜； 洪奕茜；

【作者基本信息】 上海交通大学 ， 化学工程， 2012， 硕士

【摘要】 抗冲聚丙烯材料由于各组分物理性能上的差异，成型过程中必然存在着组分的重新分布及微观相形态的变化，其分子聚集态结构以及微观相形态直接影响产品使用性能。建立准确数学模型对成型过程以及结晶行为进行模拟就显得非常重要。本文以抗冲聚丙烯材料为研究对象，利用可压缩流体流动模型和两相流动诱导结晶模型进行分析，建立了一种研究注射成型过程中聚合物结晶行为的半耦合方法。通过Moldflow软件和MATLAB软件工具对注射成型和结晶过程进行模拟分析，论文研究了注射成型过程中样品结构和工艺参数对结晶过程的影响；同时采用不同工艺参数注射成型实际样品，验证了两相流动诱导结晶模型的适用性。通过模拟分析与实际测试结果对比发现：1.产品结构、位置及厚度对成型过程与结晶过程会产生影响：剪切速率越大，温度下降越快的位置，结晶速度越快；越靠近中心层，剪切速率变小，结晶速度变慢。2.保压压力、保压时间及模具温度对成型过程与结晶过程会产生影响：模温越高，结晶度曲线上升越慢；保压压力越高及保压时间越长，结晶速率越快。更多还原

【Abstract】 The processing of impact polypropylene material determines usability of finalproduct because this process changes its microstructure and molecule structure. Inorder to forecast the usability of final product, it is necessary to model thecrystallization process and molding process of impact polypropylene.This paper focus on the establishment of compressible flow model and two-phaseflow induced crystallization model, injection molding process of impact polypropylene.Using Moldflow software and Matlab tool, this paper analyzes how the productstructure and process parameter affect the crystallization process. The two-phase flowinduced crystallization model is verified usefully through dimension measuring,mechanical property testing, DSC test of actual molding samples, which moldingunder multiple different process parameters. Also a FEA simulation model is built upusing Moldflow software to verify the crystallization model.Through modeling and analysis of crystallization process of impactpolypropylene, two conclusions are drawn:1. Product structure, location and thickness affect on the crystallization processand molding process. Where the shear rate is high, the crystallization speed ishigh. Nearer the central layer, smaller the shear rate and slower thecrystallization rate.2. Packing pressure, packing time and mold temperature also affect on themolding process and crystallization process. Under higher mold temperature,slower the crystallization speed. Increasing the packing pressure and packing time will accelerate the crystallization speed. But this trend is closely reratedwith the product structure and location.The measuring results of actual molding samples are similar to the simulationresults of crystallization model, which verified the model is applicable.更多还原