Melt Fracture in Soft Solid-Like Polymeric Materials

软固体类聚合物材料中的熔体断裂（CMMI 0926522）摘要本项目将研究一类主要工程材料的非线性力学，即，以每年几千亿磅的速度产生的缠结的聚合物液体。 具体来说，拟议的研究将探索在这些材料加工过程中发生的不同类型的类似于熔体破裂的分子机制。 将开发基于分子工程的策略来减少或消除熔体破裂，以改善这些材料的机械性能。 各种实验方法将被应用于阐明与1）通过研究它们对分子组成的依赖性，在简单剪切中屈服和失效，2）使用新的实验设计作为分子配方的函数的表面熔体破裂，3）入口材料不稳定性将用粒子进行研究-熔融塑料的机械失效长期以来阻碍了更有效地制造诸如牛奶瓶、食品杂货袋、衣服（纤维）、汽车保险杠汽车轮胎和微电子电路板。 从拟议的活动的结果可能会产生实际的解决方案，以推迟或消除制造中的熔体破裂，使许多塑料制品可以在更快的速度和更低的能源成本。 阿克伦全球聚合物学院（http：//www.agpa.uakron.edu/nn-scied-researchfeatures.html）提供基础设施，使区域高中教师和学生能够访问。 来自先前研究的六部电影最近被上传到YouTube.com，并获得了超过500次点击（关键词：聚合物流变学）。

Melt fracture in soft solid-like polymeric materials (CMMI 0926522)AbstractThis project will study nonlinear mechanics of a major class of engineering materials, i.e., entangled polymeric liquids that are produced at a rate of a few hundred billion pounds per year. Specifically, the proposed research will probe molecular mechanisms responsible for different types of fracture-like failure (technically known as melt fracture) that occur during processing of these materials. Strategies based on molecular engineering will be developed to reduce or remove melt fracture to improve the mechanical performance of these materials. Various experimental methods will be applied to elucidate true physical origins of rupture-like failures related to 1) yielding and failure in simple shear by studying their dependence on molecular composition, 2) surface melt fracture using a new experimental design as a function of molecular formulation, 3) entry material instability to be investigated with particle-tracking velocimetry and correlated with gross melt fracture.The mechanical failure of molten plastics has long prevented more efficient making of such common items as milk bottles, grocery bags, clothing (fibers), car bumpers, automobile tires and microelectronic circuitry boards. Results from the proposed activities may produce practical solutions to postpone or remove melt fracture in manufacturing so that many plastics articles can be made at a faster speed and lower energy cost. Akron Global Polymer Academy (http://www.agpa.uakron.edu/nn-scied-researchfeatures.html) provides the infrastructure to allow access to regional high school teachers and students. Six movies from previous research have recently been uploaded onto YouTube.com and received over five hundred hits (key word: Polymer Rheology).