Postdoctoral Fellow; PREP

PREP Research Associate Durability Assessment of Polymeric Materials Used in Civil Infrastructure Applications

This position is part of the National Institute of Standards (NIST) Professional Research Experience (PREP) program. NIST recognizes that its research staff may wish to collaborate with researchers at academic institutions on specific projects of mutual interest and thus requires that such institutions be the recipients of a PREP award. The PREP program requires staff from a wide range of backgrounds to work on scientific research in many areas.

Employees in this position will perform technical work that underpins the scientific research of the collaboration.

The work will entail:
The PREP Researcher will conduct laboratory accelerating weathering exposure experiments on various polymer systems used in infrastructure applications, which will include building envelope materials, protective coatings, crack repair materials, and fiber reinforced polymer composite (FRP) retrofits. The PREP Researcher will help to identify select polymeric infrastructure materials in widespread use based on current limitations of these materials, identified research gaps, and identified durability issues.

Accelerated weathering experiments will primarily take place on the state-of-the-art NIST SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) device which allows precise control of temperature and relative humidity while exposing samples to highly uniform ultraviolet (UV) exposure. Other weathering exposure experiments in humidity chambers, a freeze/thaw chamber, a corrosion chamber, commercial UV-weathering devices, or at two outdoor weathering fields may be conducted.

The PREP researcher will collect material property change data resulting from degradation and develop test configurations and methods to measure performance changes of an infrastructure material with respect to its given application (e.g., increased water penetration of a building envelope material). Alongside structural engineers, weathering data criteria will be collaboratively incorporated into design equations and structural models.

• Review literature and sample degradation results from previous SPHERE and outdoor weathering experiments.
• Help identify a select few polymeric infrastructure materials for durability assessment that will have a high impact for stakeholders. Identification efforts should involve literature reviews, stakeholder engagement, and market research. Building envelope materials will be highest priority.
• Conduct accelerated weathering exposure on the NIST SPHERE and on other weathering devices, as appropriate.
• Characterize the chemical, optical, and mechanical property changes of weathered infrastructure polymer samples using techniques such as ATR-FTIR, Raman, UV-Vis, color and gloss tests, DSC, TGA, pull-off testing, three-point bending tests, moisture absorption tests, infrared thermography, and microscopy.
• Develop test configurations and test methods to measure performance changes of a material within a given infrastructure application. This may include water vapor transmission tests, corrosion tests, tensile tests, impact and tear resistance tests, etc.
• Maintain the NIST SPHERE in collaboration with NIST technicians: this includes collecting, recording, and analyzing irradiance data.
• Construct a UV‑degradation database for correlating materials-structure-performance properties. Contribute to a NIST SPHERE metadata database.
• Present results within the group and other related meetings, write protocols, technical reports, and prepare…