BFRL Program

Service Life Prediction (SLP) of Nanostructured Polymeric Materials

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Polymeric materials are used in the construction and building industries in a myriad of applications including protective coatings, siding, roofing, windows, doors, pipes, and geotextiles.  They can be combined with fibers to form composites that have enhanced properties, enabling them to be used as structural and load-bearing members. Polymers offer many advantages over conventional materials including lightness, corrosion resistance, and ease of processing and installation.

There is currently no established, scientifically-based methodology for accurately and quantitatively predicting life cycle performance of polymeric construction materials in their end-use environment. The addition of nanoparticles to polymeric matrices further increases the difficulty of predicting life cycle performance.  Degradation and nanoparticle release phenomena in nanostructured materials are inherently complex and involve numerous component interactions and multifunctional (chemical, physical, and mechanical) responses that operate over extremely large length and time scales. Nanoscale materials also possess unique properties (high surface area, high surface reactivity, and large interparticle forces) that affect many initial and long-term properties. Thus, new metrologies and methodologies that are radically different from the approaches currently used are required to obtain the necessary data for accurately modeling lifetimes and particle release behavior in new nanostructured materials.

In 2006, BFRL became the first research team to successfully and quantitatively link field and laboratory exposure results for an unfilled, model epoxy coating using a reliability-based methodology. Success in applying this methodology in predicting the service life of the epoxy coating has provided BFRL with an opportunity to move into the study of nanostructured systems, which includes polymers filled with nanoscale materials. Measurement science is being developed by BFRL researchers over a wide range of length and time scales to enable quantitative prediction of the life cycle performance¹ of nanostructured polymeric materials.

The linkage between field and laboratory exposures is studied using a reliability-based methodology for the three major classes of polymers: thermoset, thermoplastic, and elastomers. High resolution microscopy, spectroscopy and nanomechanical testing devices are being used to elucidate the effects that nano-fillers have on the chemical and physical properties of nanomaterials, and as well as on the service lives of filled polymer systems. Temperature, relative humidity, and spectral UV are the primary environmental factors of interest. BFRL is focusing is on metal oxide particles and carbon nanotubes, which are nano-scale fillers of interest in many structural applications.

Release of nanoparticles occurs in-service via environmental degradation and incineration through thermal, chemical, mechanical, and photolytic decomposition of nanostructured polymeric materials. The release rates and properties of these nanoparticles could have environmental, health and safety impacts. NIST is quantitatively measuring release rates, chemical compositions, morphologies, and size distributions of aerosolized nanoparticles, using a number of advanced methods. Total mass loss and depletion of nanostructured materials during environmental exposure is being characterized with high resolution nano-gravimetry and infrared spectroscopy. Such models will be instrumental in designing improved nanocomposite materials.

[1] Life cycle is defined as material performance from manufacturing to decommissioning/disposal.

Component Projects:

• Economic Impacts of Improved Service Life Prediction

• Surface Mechanical Characterization of Polymers  (PSIC)

• Reliability Approach for Relating Outdoor and Accelerated Laboratory Aging for Nanostructured Polymeric Systems

• Photoreactivity of Titanium Dioxide Nanostructures

• Metrologies for Characterizing Filler Dispersion, Multi-scale Structure, and Optical Properties of Polymeric Materials

• Service Life Prediction for Building Joint Sealants

• Quantifying Micro-scale Mechanical and Fracture Properties in Nanocomposite Materials

• Development of an Autonomous Precision Positioning and Measurement Testbed

• Characterization of Nanoparticle Release Behavior

Contact:
Joannie Chin
(301) 975-6815
joannie.chin@nist.gov

 

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