This dataset contains mechanical testing data at two different loading rates for two different aging conditions (wet and dry at 70 °C) for five different extraction time points for ultra high molar mass polyethylene (UHMMPE) unidirectional (UD) laminate. In each folder there is a spreadsheet (.csv) with the test data collected during loading, and a (.avi) video file for each of the tests done under those conditions.

Flexible Unidirectional (UD) composite laminates are commonly being used for ballistic-resistant body armor. These laminates comprise UD layers, each constructed by laminating thin layers of high-performance fibers held in place using binder resins, with the fibers in each layer oriented parallel to each other. As these materials are used in body armor, it is important to investigate their long-term reliability, particularly with regards to exposure to temperature and humidity as these are known causes of degradation in other commonly used body armor materials. This work investigates the tensile behavior of a poly(p-phenylene terephthalamide), reffered to as PPTA, flexible UD laminate, both unaged and aged for up to 150 d at accelerated conditions of 70 °C and 76 % relative humidity (RH). Tests on aged specimens were performed at three different crosshead displacement rates and three different gauge lengths. Unaged characterization additionally included three different widths and two other configurations. Certain commercial equipment, instruments, or materials are identified in this dataset in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.

Traditionally, soft body armor has been made from materials such as poly(p-phenylene terephthalamide) (PPTA) and ultra-high molar mass polyethylene (UHMMPE). However, to diversify the fiber choices in the United States body armor market, copolymer fibers based on the combination of 5-amino-2-(p-aminophenyl) benzimidazole (PBIA) and PPTA were introduced. Little is known regarding the long-term stability of PBIA fibers, but as condensation polymers, they have potential sensitivity to moisture and humidity. Ballistic resistance and other critical structural properties of these fibers are predicated on their superior mechanical properties. Therefore, it is important to characterize the strength of these materials and understand their vulnerability to environmental conditions to evaluate their use lifetime in safety applications. Three PBIA-based fibers were selected for the study. The fibers were thoroughly washed to remove an organic coating, which held the individual fibers in each yarn bundle together, allowing for the disentangling of single fibers for mechanical testing. Molecular spectroscopy and single fiber tensile testing were performed on the fibers to characterize changes in their chemical structure, tensile strength, and strain to failure as a function of exposure time to four different hydrothermal ageing conditions.

This dataset consists of tensile tests performed by directly gripping single UHMMPE fibers. The tests were conducted at 11 different temperatures, and at both quasi-static and dynamic loading rates. The testing procedures are described in NISTIR 8265.

To improve the reliability and design of armor, it is imperative to understand the failure modes and the degradation rates of the materials used in armor. Despite the best efforts of manufacturers, some vulnerability of armor materials to ageing due to hydrolytic or oxidative environments is expected and may result in the degradation of material properties such as tensile strength. In this work, p-aramid yarns from two manufacturers were exposed to environmental conditions of various fixed temperature and humidity combinations. The maximum temperature and humidity condition was 70 °C and 76 % RH. Tensile tests were performed on specimens extracted at several different timepoints over the course of at least one year to determine the change in ultimate tensile strength and failure strain as a function of time, temperature, and humidity. These materials were found to be generally resistant to degradation at most conditions, showing changes of less than 10 % only at the highest temperature and humidity conditions. This data set contains failure load and failure strain values for three different aramid yarns, exposed to various conditions. It also includes Fourier Transform Infrared (FTIR) spectroscopy spectra for two of the aramids.

Data associated with experiments to examine the effect of thermal aging on the molar mass of ultra-high molar mass polyethylene fibers.

Data associated with experiments to examine the effect of thermal aging on the molar mass of ultra-high molar mass polyethylene fibers.

Flexure testing, SEM, FTIR_ATR, Acoustic testing, Electrical testing, XRD, DSC, TGA