The effect of micro and macro mixing in continuous polymer reactor systems on long chain branching frequency and structure

本研究计划旨在发展一种预测聚合物分子中长链支化结构和频率的数学模拟方法。 聚合物材料通常在搅拌釜反应器容器中制备，然后通过熔融和成型加工成最终产品。这些产品的例子包括管道、瓶子、计算机机箱、薄膜和粘合剂。聚合物材料的加工性能取决于聚合物的流变性，而流变性又取决于聚合物链的分子性能（例如组成、分子量分布、长链支化类型、频率和长度）。 这些分子性质由初始反应容器中的条件决定。 获得所需的流变性能需要非常昂贵的试错实验。为了减少这一点，我们必须发展聚合物分子性质和流变性能之间的关系。 拟议的研究重点是发展这种关系，是基于，并扩展，以前的工作，开发数学模拟方法的基础上的物理脉冲的方法。 这产生了一个数学模型，被应用到商业聚合过程中使用的橡胶industrial.The目前提出的工作包括开发一个模拟方法，能够预测长链支化频率和结构的影响，在分子水平上的混合（包括扩散效应）的阴离子polymerization中产生的聚合物链，成功地预测了完整的分子量分布。 这将是物理脉冲法阐明高分子链扩散速率的影响。 为了满足开发一种方法，给出准确的，定量的预测，我们将合成和分析许多聚烯烃不同的长链支化结构和频率的目标。

This research project aims at developing a mathematical simulation method for predicting long chain branching structure and frequency in polymer molecules.  Polymeric materials are typically made in stirred tank reactor vessels and then processed into final products by melting and shaping. Examples of these products include pipes, bottles, computer cases, films and adhesives. The processing properties of the polymeric materials depend on the rheology of the polymers which, in turn, depends on the molecular properties of the polymer chains (e.g. composition, molecular weight distribution, long chain branching type, frequency and length).  These molecular properties are determined by conditions in the initial reaction vessel.  Obtaining desired rheological properties requires much expensive trial and error experimentation. To reduce this we must develop relationships between polymer molecular properties and rheological properties.  The proposed research focuses on developing such relationships and is based on, and extends, previous work that developed mathematical simulation methods based on the method of Physical Pulses.  This produced a mathematical model that was applied to a commercial polymerization process used by the rubber industry, successfully predicting the full molecular weight distributions for polymer chains produced in an anionic polymerization.The current proposed work comprises developing a simulation method capable of predicting long chain branching frequency and structure as affected by mixing (including diffusion effects) at the molecular level.  This will be the Method of Physical Pulses Incorporating the Effects of Polymer Chain Diffusion Rates.  In order to satisfy the goal of developing a method that gives accurate, quantitative predictions we will synthesize and analyze many polyolefins with varying long chain branching structure and frequency.