U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by:

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 192

Determination of the Complex Modulus of a Supported Ultra-Thin Polymer Film

October 12, 2021
Author(s)
Christopher C. White, Wen-Li Wu
A novel technique to quantitatively measure the complex modulus of ultra-thin polymer films (sub micron) is described. This technique employs a new mechanical impedance expression developed from a two-layer viscoelastic media model. This result is combined

EFFECTS OF PRE-STRAIN ON THE NON-LINEAR VISCOELASTIC PROPERTIES OF A MODEL SEALANT

November 18, 2020
Author(s)
Christopher C. White, Donald L. Hunston, Kar tean Tan
The non-linear viscoelastic properties of a model sealant were measured using stress relaxation tests conducted at different strain levels, x. Some specimens were measured with no previous strain history while others were given a preconditioning that

Bayesian Hierarchical Models for Service Life Prediction of Polymers

August 5, 2020
Author(s)
Adam L. Pintar, Christopher C. White, Li Piin Sung
Service life prediction for polymers remains an elusive goal. In this chapter, a general methodology first described in a previous study \cite{pintar2018predicting} is recapitulated and extended. A central component of the methodology is a Bayesian

Macroscopic degradation behaviors of polyethylene under the influence of UV radiation and temperature

February 17, 2020
Author(s)
Hsiang C. Hsueh, Jae H. Kim, Sara Orski, Andrew Fairbrother, Deborah Jacobs, Donald L. Hunston, Christopher C. White, Li Piin Sung, Lakesha Perry
Accelerated weathering tests were performed to investigate the effects of multiple ultraviolet (UV) light intensities and temperatures on the tensile behavior of high-density polyethylene (HDPE). In the macroscopic degradation behavior of HDPE, tensile

Validating Predictive Models with Outdoor Data

October 17, 2019
Author(s)
Christopher C. White, Donald L. Hunston, Li Piin Sung, Hsiang C. Hsueh, Adam L. Pintar, Deborah S. Jacobs
The NIST service life prediction program has demonstrated success in producing validated predictions for the property change resulting from outdoor exposure for a range of polymer systems including Epoxy, Polyethylene, Polyester, Polyethylene terephthalate

Degradation of sunglasses filters after long-term irradiation within solar simulator

September 18, 2019
Author(s)
Deborah Jacobs, Mauro Masili, Fernanda O. Duarte, Liliane Ventura, Christopher C. White
In our previous investigations on sunglasses standards, limits and requirements have been suggested for ocular safety. In this paper we evaluate the degradation of the lenses (category and ultraviolet protection) as sunglasses are exposed to solar

Temperature and light intensity effects on the photodegradation of high-density polyethylene

May 11, 2019
Author(s)
Andrew W. Fairbrother, Hsiang C. Hsueh, Jae Hyun Kim, Deborah S. Jacobs, Lakesha N. Perry, David G. Goodwin, Christopher C. White, Stephanie S. Watson, Li Piin Sung
The photodegradation of polymers poses a serious challenge to their outdoor application, and results in significant financial loss due to early or unexpected system failure. A better understanding of their degradation kinetics aids the improvement of

Exposure Study on the Aging of PTFE and Ceramic Diffusers

February 6, 2019
Author(s)
Benjamin K. Tsai, Catherine C. Cooksey, David W. Allen, Christopher C. White, Walter E. Byrd, Deborah S. Jacobs
This paper describes efforts to quantify the effects of aging in the ultraviolet (UV) on polytetrafluoroethylene (PTFE) and ceramic samples. Long term UV aging may significantly alter the reflectance factor and cause an error in the calibration of

Service Life Prediction Models to Predict Building Skin Failures

October 1, 2018
Author(s)
Christopher C. White, Donald L. Hunston, Adam L. Pintar
Determination of the in-service performance and failure of a building envelope material exposed to outdoor weathering has been a significant research goal for the last 100 years. Typically, estimations of the time to failure or durability of a material is

A Kinetics Based Models for Environmentally Induced Sealant Degradation

February 12, 2018
Author(s)
Donald L. Hunston, Christopher C. White
Caulks and sealants are a critical part of any structure that is exposed to the environment. Although they are good materials, they eventually fail, and the failure is often difficult to detect before extensive damage is generated by water ingress or loss