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Combined theoretical and experimental study of the linear rheology of model and commercial polymers.

机译：模型和商业聚合物线性流变学的理论和实验研究相结合。

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摘要

Polymer rheology is a very sensitive indicator of polymer long chain branching, and therefore can be used as a tool to determine polymer structures. This dissertation is thus focused on the study of the relationship between polymer linear viscoelastic properties and polymer structures using both rheological experiments as well as theoretical modeling methods applied to both model polymers and commercial polymers. In this work, the two advanced tube models, namely the "hierarchical model" and the "BOB" model, were firstly introduced and compared before being applied to predict the rheological properties of model polymer melts and commercial polymer melts. For the model polymer melts, symmetric and asymmetric "H" model polybutadienes of high quality were synthesized by a collaborator using a novel synthesis strategy, and characterized by another collaborator using temperature gradient interaction chromatography (TGIC) as well as by the rheological measurements carried out in our lab. The "hierarchical model" was employed to predict their rheological behaviors as well as to identify the impurities in the materials using the "analytical rheology" concept. After validating the tube model theory successfully on the model polymer melts, we developed and validated a method to obtain tube model parameters for commercial polyethylene copolymers and tried to access the validity of the modeling predictions for commercial polyolefins. We are the first team to work on the asymmetric "H" shaped polymers. The most interesting findings in this work include: (1) The methods of TGIC, rheology measurement and theory modeling need to be combined to determine reliable long-chain branching information for branched polymers, and to identity the impurities in the materials. (2) The polydispersity of a branched polymer is not only due to molecular weight variations but also due to different molecular structures. (3) Even long-chain branching levels as low as 0.335 long chain branches per million carbon atoms can be detected by polymer rheology, which is not detectable by any other experimental method. (4) The "hierarchical model" can predict the rheology for both model polymers, such as linear-, star-, and H-shaped polymers, and commercial polyolefins, and thus it is a useful tool to predict polymer linear rheology.
机译：聚合物流变学是聚合物长链支化的非常敏感的指标，因此可以用作确定聚合物结构的工具。因此，本论文着重于使用流变实验以及应用于模型聚合物和商业聚合物的理论建模方法研究聚合物线性粘弹性和聚合物结构之间的关系。在这项工作中，首先引入并比较了两个先进的管模型，即“分层模型”和“ BOB”模型，然后再用于预测模型聚合物熔体和商业聚合物熔体的流变性。对于模型聚合物熔体，合作者使用一种新颖的合成策略合成了高品质的对称和不对称“ H”模型聚丁二烯，并使用温度梯度相互作用色谱法（TGIC）通过另一位合作者进行了流变测量来表征在我们的实验室。使用“层次模型”来预测其流变行为，并使用“分析流变”概念来识别材料中的杂质。在成功地对模型聚合物熔体进行管模型理论验证之后，我们开发并验证了一种用于获得商品聚乙烯共聚物的管模型参数的方法，并试图获得商品聚烯烃模型预测的有效性。我们是第一个研究不对称“ H”形聚合物的团队。这项工作中最有趣的发现包括：（1）TGIC，流变学测量和理论建模的方法需要结合起来，以确定支链聚合物的可靠长链支化信息，并鉴定材料中的杂质。 （2）支链聚合物的多分散性不仅是由于分子量的变化，还在于分子结构的不同。 （3）通过聚合物流变学甚至可以检测到低至每百万个碳原子0.335个长链分支的长链支化水平，这是任何其他实验方法都无法检测到的。 （4）“分层模型”可以预测线性，星形和H形聚合物等模型聚合物和市售聚烯烃的流变性，因此它是预测聚合物线性流变性的有用工具。

著录项

  • 作者

    Chen, Xue.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Chemistry Polymer.;Engineering Materials Science.;Engineering Chemical.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 172 p.
  • 总页数 172
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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