SBIR Phase II: An Innovative Normal Stress Sensor System for Complete Characterization of Polymer Shear Flow Properties

这个小型企业创新研究（SBIR）第二阶段项目将解决一些技术改进，以成功商业化包含单片微型电容压力传感器的新型MEMS传感器板。如图1所示，传感器板可以精确测量第一（N1）和第二（N2）正应力差，这是各类粘弹性液体重要的非线性弹性流动特性。在第二阶段，传感器封装和引线转移到传感器将适合大批量，高质量的传感器板的制造。一个版本将在较低的压力下进行优化测量，另一个版本将在较高的温度和压力下对熔融商业热塑性塑料进行优化测量。后一种版本的传感器板直径更小，可以在更高的剪切速率下对更小的样品进行测量，并且包含微型温度传感器，可以精确补偿传感器校准常数随温度的变化。改进将在各种商用聚合物系统和其他重要类型的粘弹性液体中进行测试。这种新型传感器板将满足市场对一种廉价仪器的关键需求，用于全面表征熔融热塑性塑料的剪切流动特性。与之竞争的替代技术是力再平衡传感器（FRT），它价格昂贵，并且在大样本中效果最好。它是更简单/更便宜的适应传感器板而不是传感器现有的流变仪。因此，传感器板具有显著的商业潜力，以满足被压抑的需求，以一种廉价的方式升级流变仪，以允许流动弹性测量。

This Small Business Innovation Research (SBIR) Phase II project will address several technical improvements needed for successful commercialization of a novel MEMS sensor plate containing monolithic miniature capacitive pressure sensors. As shown in Phase I, the sensor plate can be used to accurately measure the first (N1) and second (N2) normal stress differences, which are important nonlinear elastic flow properties of various classes of viscoelastic liquids. In Phase II, sensor packaging and lead transfer to the sensors will be made suitable for high volume, high quality manufacturing of sensor plates. One version will be optimized for measurements at lower pressures and another version optimized for measurements on molten commercial thermoplastics at higher temperatures and pressures. The latter version of the sensor plate will be smaller in diameter to make possible measurements on smaller samples at higher shear rates, and will contain miniature temperature sensors that will enable accurate compensation for changes in sensor calibration constant with temperature. Improvements will be tested with a wide variety of commercial polymer systems and other important classes of viscoelastic liquids. This novel sensor plate will meet the critical market need for an inexpensive instrument for fully characterizing shear flow properties of molten thermoplastics. The competing alternative technology, the force rebalance transducer (FRT) is expensive and works best with large samples. It is simpler/less expensive to adapt a sensor plate rather than a transducer to existing rheometers. Hence the sensor plate has significant commercial potential to satisfy pent-up demand for an inexpensive way to upgrade rheometers to allow flow elasticity measurements.