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

这个小企业创新研究（SBIR）第一阶段项目描述了一种独特的仪器，能够量化溶液、糊状物和熔体的拉伸流变行为。在这个仪器中，少量的流体在两个板之间迅速拉伸，形成一个液体桥，当流体在重力和表面张力的作用下排出时，随后监测直径的减小。将流变模型与数据进行比较，可以提取粘度、表面张力、弹性和与拉伸流动有关的其他参数。目前，研究人员纯粹依赖于简单的剪切表征或毛细管流变学，这两种方法都不能提供关于拉伸流动行为的明确定量信息。硬件和分析软件的集成将使仪器具有通用性和独特性。对于所有加工流程（如挤压、填充、泵送、吹塑、喷涂等）都涉及拉伸流场的行业来说，该仪器将是无价的。它将在工业中作为质量控制工具和研究级设备而发挥作用。此外，它还将用于学术界，因为没有简单的定量分析设备来检查流体的排水（和灯丝形成）行为。此外，所描述的仪器具有许多内在的优点，使其成为车间安装的理想选择。它是紧凑的（我们设想的设计将有一个占地面积小于0.1平方米）和坚固（与少数运动部件，它将容忍灰尘和振动）。它还应该易于使用，特别是在实验室内部比较（或楼层质量控制）的索引模式下。可移动版将允许容易清洗和改变板表面化学的能力。最后，样本体积很小。

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.