SBIR Phase I: A Novel Instrument for the Determination of Extensional Rheology

这个小型企业创新研究(SBIR)第一阶段项目描述了一种独特的仪器，能够量化溶液、浆料和熔体的拉伸流变行为。在这台仪器中，少量的液体在两块平板之间快速拉伸，形成液桥，随后在重力和表面张力的作用下，随着液体的流出，直径的减小被监测。将流变模型与数据进行比较，可以提取与伸展流动有关的粘度、表面张力、弹性和其他参数。目前，研究人员单纯依赖于简单的剪切表征或毛细管流变仪，这两种方法都不能提供关于拉伸流动行为的明确的定量信息，硬件和分析软件的集成将使仪器既通用又独特。该仪器对于所有加工流程(如挤出、充填、泵送、吹塑、喷涂等)的工业来说都将是无价的。涉及到伸展的流场。它将在工业中作为质量控制工具和研究级设备使用。此外，它将对学术界有用，因为学术界没有简单的定量分析设备来检查流体的排放(和细丝形成)行为。此外，所描述的仪器具有许多固有的优点，使其成为车间安装的理想选择。它紧凑(我们设想的设计占地面积将小于0.1平方米)，坚固耐用(几乎没有移动部件，它将容忍灰尘和振动)。它也应该易于使用，特别是在用于实验室内部比较(或最低水平质量控制)的索引模式下。可拆卸的板材可以方便地清洗，并且能够改变板材表面的化学成分。最后，样本量将很小。

This Small Business Innovation Research (SBIR) Phase I project describes a unique instrument capable of quantifying the extensional rheological behavior of solutions, pastes and melts. In this instrument a small quantity of fluid is rapidly stretched between two plates to form a liquid bridge, and the diameter decrease is subsequently monitored as the fluid drains under gravity and surface tension. Comparison of rheological models with the data allows one to extract viscosity, surface tension, elasticity and other parameters relating to extensional flows. Currently, researchers rely purely on simple shear characterization or capillary rheometry, neither of which can provide unambiguous quantitative information about extensional flow behavior.The integration of hardware and analysis software will make the instrument both versatile and unique. The instrument will be invaluable to industry where all processing flows (such as extrusion, filling, pumping, blow molding, spraying etc.) involve extensional flow fields. It will find utility in industry as both a quality control tool and a research grade device. Additionally it will be of use to academia, where no simple quantitative analytical device exists for examining the draining (and filament forming) behavior of fluids. In addition the instrument described has a number of intrinsic advantages that make it ideal for a shop floor installation. It is compact (our envisioned design will have a footprint smaller than 0.1 m 2 ) and robust (with few moving parts it will be tolerant of dust and vibration). It should also be easy to use, especially in an indexing mode for intra-lab comparisons (or floor level quality control). The removable plates will allow easy cleaning and the ability to change plate surface chemistry. Finally the sample volumes will be small.