Analysis of dispersive mixing processes in polymer melts

聚合物熔体分散混合过程分析

• 批准号: 285787361
• 负责人: Professor Dr.-Ing. Christian Bonten
• 金额: --
• 依托单位: Institut für Kunststofftechnik (IKT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/285787361?language=en
• 关键词: Analysis; dispersive; mixing; processes; polymer

Thermoplastic polymers are much more multipurpose applicable as metals, ceramics and other organic and anorganic materials. This high application potential is based on their thermoplastic processibility at comparatively low temperatures and on their simple modificability in order to obtain application specific properties (addition of particles or droplets and functional components, generation of blends with defined morphology). The homogeneity of the melt is the most important criteria for product quality in compounding and processing. Basic knowledge for description and quantifying of material homogeneity in complex material systems like polymer blends and with additives modified polymer compounds are less developed. For that reason continuum mechanical fundaments shall be elaborated for mixing processes in this research project. The pseudo plastic flow behavior and viscoelastic properties of the polymer melt influence dispersive mixing processes. The numerical simulation of the flow in wedge - rectangular - slit (WRS) applying finite - difference - methods (FDM) gives the possibility elongation and shear strains to calculate for droplet deformation and breakage, critical stresses for droplet break to determine and criteria to define optimized design and process parameters for dynamic mixing systems.The aim of the research project is to calculate the superimposed planar elongation and shear flow for high viscos, pseudo plastic and viscoelastic polymer melts in WRS, which represents the basic element of dispersive mixing shear units. Detailed representations of local elongation and shear strains, local elongation and shear rates, local normal and shear stresses and local residential times of melt particles shall giveinformation from working and efficiency of dispersive mixing shear units. The simulation program can be used than as tool for design and optimaizing of dispersive mixing geometries.The results of the FDM - simulation must be verified experimentally. A special designed experimental device shall be developed and build in order to inject small high viscos melt droplets in to the main flow the lower viscos second melt at the area of the entry section of the shear unit. Droplet deformation and breakage shall be analyzed, quantified and with calculated values compared.

热塑性聚合物更适用于金属、陶瓷和其他有机和无机材料。这种高应用潜力是基于它们在相对较低的温度下的热塑性加工性能，以及它们为了获得特定应用特性(添加颗粒或液滴和功能组分，产生具有定义形态的共混物)的简单可变性。在配料和加工中，熔体的均匀性是衡量产品质量的最重要标准。描述和量化复杂材料体系(如聚合物共混物和具有添加剂的改性聚合物化合物)中的材料均匀度的基本知识较少。为此，应在本研究项目中详细阐述混合过程的连续介质力学基础。聚合物熔体的假塑性流动行为和粘弹性影响着分散混合过程。采用有限差分法对楔形矩形缝隙(WRS)内的流动进行了数值模拟，给出了用于计算液滴变形和破碎的伸长率和剪切应变的可能性、用于确定液滴破裂的临界应力的准则和确定动态混合系统优化设计和工艺参数的准则。熔体颗粒的局部拉伸和剪切应变、局部拉伸和剪切速率、局部法向应力和剪切应力以及局部停留时间的详细表示应提供分散混合剪切机组的工作和效率信息。该模拟程序可作为色散混合几何结构设计和优化的工具，其模拟结果必须经过实验验证。应开发和建造一种特殊设计的实验装置，以便将小的高粘度熔滴注入剪切单元入口区较低粘度的第二熔体的主流中。应对液滴变形和破碎进行分析、量化，并与计算值进行比较。