ABLATION PERFORMANCE AND CHARACTERIZATION OF THERMOPLASTIC POLYURETHANE ELASTOMER NANOCOMPOSITES

摘要

This study involves analysis of the ablation performance of various thermoplastic polyurethane elastomer nanocomposites (TPUNs) as well as scanning electron microscopy (SEM) characterization of the post-test material samples. The TPUNs being studied are composed of a TPU polymer matrix combined with one of three different nanomaterials: multi-walled carbon nanotubes (MWNTs), montmorillonite (MMT) nanoclays, or carbon nanofibers (CNFs). For each material type, there are varying nanomaterial weight percentages ranging from 2.5 % up to 20 %. These different TPUNs will be tested through the use of an Oxyacetylene Test Bed (OTB) designed to test ablative materials and capable of producing a heat flux of up to 1400 W/cm2. This test bed includes a data acquisition (DAQ) system that allows for the in-situ temperature measurement of the test sample using embedded thermocouples. As the sample are exposed to a heat flux of 1000 W/cm2 for a duration of 25 seconds, this DAQ system is used to measure three heat soak temperature of the TPUN sample at varying distances from the front face. Physical measurements of the samples' mass and dimensions will be used to determine mass loss, erosion depth, and char thickness of the TPUN materials after ablation testing. Combining these measurements will provide an overview of the relative ablation performance of each TPUN. SEM analysis will be utilized after ablation testing to characterize the char structure of the post-test samples in order to further understand their ablation mechanisms and the reason for their relative performances.