Rheological properties of multiphase polymer systems

该项目的总体目标是开发新的流变学方法和模型，以表征和预测聚合物多相体系的性能，并优化其与加工有关的性能。这个创新的计划应该会产生新的和高度相关的数据，以及这些复杂系统建模的新想法。 用性能良好的聚合物共混物(如聚丙烯(PP)和茂金属催化的乙烯共聚物(EC)的烯烃共混物)研究了外加应变对分散相体积分数和聚合物组分弹性的影响。将考察添加的纳米颗粒在改变组分的性质和稳定共混物形态方面的作用。实验数据将与最近文献中提出的预测不相容混合物中形态变化的罕见模型的预测进行比较。这些模型将被推广以考虑聚合物组分的弹性。 对填充聚合物的流变特性的了解仍然很少，特别是对纳米粒子和相互作用的粒子的悬浮液。我们将研究由多壁碳纳米管(MWCNTs)组成的模型聚合物悬浮液在牛顿环氧树脂和Boger流体中的非线性粘弹性特性，以模拟粘弹性效应。未经处理和处理的WMCNT将使用3辊搅拌机混合到环氧液或博格液中。我们将利用一种独特的二维流变学技术，建立这些模型悬浮液的流变行为，作为浓度、多壁碳纳米管的表面处理、基质的弹性和预剪切(变形历史)的函数，以探测流动中纳米颗粒的内部结构、各向异性和取向。这些数据将被用来评估和推广现有的结构和杰弗里类型的模型。

The overall objective of this project is to develop novel rheological methods and models to characterize and predict the performances of polymer multiphase systems and optimize their properties in relation to processing. This innovative program should generate new and highly pertinent data, as well as new ideas for the modeling of these complex systems. Well characterized polymer blends (such as olefin blends of polypropylene (PP) and metallocene catalyzed ethylene copolymers (EC)) will be used to investigate the effect of imposed strain on the morphological changes as functions of the volume fraction of the dispersed phase and the elasticity of the polymer components. The role of added nanoparticles to modify the properties of the components and stabilize the morphology of the blends will be examined. The experimental data will be compared to the predictions of the rare models proposed in the recent literature to predict morphological changes in immiscible blends. These models will be generalized to account for the elasticity of the polymer components. The understanding of the rheological properties of filled polymers remains very poor, especially for suspensions of nano and interactive particles. We will examine the non-linear viscoelastic properties of model polymer suspensions consisting of multiwalled carbon nanotubes (MWCNTs) in a Newtonian epoxy and Boger fluids to mimic viscoelastic effects. Untreated and treated WMCNTs will be mixed to an epoxy or Boger fluids using a 3-roll mixer. We will establish the rheological behavior of these model suspensions as functions of concentration, surface treatment of the MWCNTs, elasticity of the matrix and pre-shearing (deformation history), using a unique 2D rheometric technique developed to probe the internal structure, anisotropy and orientation of nanoparticles under flow. The data will be used to assess and generalize existing structural- and Jeffery-type models.