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Search Publications by: Xiaohong Gu (Fed)

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Displaying 1 - 25 of 68

Microstructure changes during failure of PVDF-based photovoltaic backsheets

July 21, 2022
Stephanie Moffitt, Po-Chang Pan, Lakesha Perry, Michael Kempe, Jared Tracy, Kaushik Choudhury, Xiaohong Gu
The backsheet layer of a solar module provides a safety and environmental barrier to the high voltages running through the photovoltaic (PV) cells and electrical contacts within the core of the module. However, in the past decade, backsheet cracking has

Study of Photodegradation of Epoxy Polymer by Using Slow Positron Annihilation Spectroscopy

October 12, 2021
R Zhang, Xiaohong Gu, H Chen, J Zhang, Y Li, Tinh Nguyen, T C. Sandreczki, Y C. Jean
Slow positron annihilation spectroscopy (SPAS) has been used to study the early stage of epoxy photodegradation. Spin-coated samples of a crosslinked epoxy were prepared by stoichiometrically mixing a diglycidyl ether of bisphenol A epoxy resin with 1,3

Graphene oxide/waterborne polyurethane nanocoatings: Effects of graphene oxide content on performance properties

January 15, 2020
David G. Goodwin, Coralie Bernard, Xiaohong Gu, Mat Celina, Marc R. Nyden, Deborah S. Jacobs, Li Piin Sung, Tinh Nguyen
Graphene oxide (GO) is a good nanofiller candidate for waterborne coatings because of its outstanding physical and mechanical properties, good dispersibility in water, and low cost. Here, we report on the performance of a one-part, water-borne polyurethane

Differential degradation patterns of photovoltaic backsheets at the array level

February 4, 2018
Andrew W. Fairbrother, Matthew Boyd, Yadong Lyu, Julien Avenet, Peter Illich, Michael Kempe, Brian P. Dougherty, Laura Bruckman, Xiaohong Gu
Photovoltaic backsheet degradation is commonly related to end-of-life failure of a module, and as such is an important factor in system reliability and longevity. Some module manufacturers have recently begun utilizing non-fluoropolymer-based backsheets in

Interlaboratory study towards a climate-specific test: spectroscopic characterizations of EVA in glass/EVA/glass systems

February 23, 2016
Jae Hyun Kim, Christopher M. Stafford, Yadong Lyu, Li C. Yu, Chiao-Chi Lin, Tinh Nguyen, Xiaohong Gu
EVA as an encapsulant material is exposed to various UV irradiation, thermal cycles, and humidity conditions. Degradation of EVA can reduce not only power generation due to yellowing, but also a structural integrity of a PV module. In order to investigate

New Insights into Subsurface Imaging of Carbon Nanotubes in Polymer Composites via Scanning Electron Microscopy

February 4, 2015
Minhua Zhao, Bin Ming, Jae-Woo Kim, Luke J. Gibbons, Xiaohong Gu, Tinh Nguyen, Cheol Park, Peter T. Lillehei, John S. Villarrubia, Andras Vladar, James A. Liddle
Despite many studies of subsurface imaging of carbon nanotube (CNT)-polymer composites via scanning electron microscopy (SEM), significant controversy exists concerning the imaging depth and contrast mechanisms. We studied CNT-polyimide composites and, by

A Quantitative Study of Nanoparticle Release from Nanocoatings Exposed to UV Radiation

April 7, 2014
Li Piin Sung, Deborah S. Jacobs, Justin M. Gorham, Savelas A. Rabb, Xiaohong Gu, Lee L. Yu, Tinh Nguyen
Nanoparticles are increasingly used in polymer coatings (i.e., nanocoatings) to improve multiple properties of traditional coatings such as mechanical, electrical, gas barrier, and UV resistance. These high performance nanocoatings are often used in

Characterization of Surface Accumulation and Release of Nanosilica During Irradiation of Polymer Nanocomposites with Ultraviolet Light

August 12, 2012
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Savelas A. Rabb, Paul E. Stutzman, Justin M. Gorham, Xiaohong Gu, Lee L. Yu, Joannie W. Chin
Nanofillers are increasingly used for enhancing multiple properties of polymeric materials in many applications. However, polymers are susceptible to photodegradation by solar ultraviolet (UV) radiation Therefore, nanofillers in a polymer nanocomposite

More Durable or Vulnerable? --- Effect of Nanoparticles on Long-Term Performance of Polymeric Nanocomposites during UV Exposure

July 2, 2012
Xiaohong Gu, Minhua Zhao, Stephanie S. Watson, Tinh Nguyen, Joannie W. Chin, Jonathan W. Martin, Dongmei Zhe, Guodong Chen
Polymers are widely used as exterior coatings in buildings, bridges, aircrafts, and automobiles for both protection and aesthetic purposes. However, the sustainability and service life of the applied coatings is limited due to the photodegradation of

Fate of nanoparticles during life cycle of polymer nanocomposites

July 6, 2011
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Xiaohong Gu, Justin M. Gorham, Paul E. Stutzman, Deborah S. Jacobs, Walter E. Byrd, John W. Hettenhouser, Joannie W. Chin
Nanoparticles are increasingly used in consumer and structural polymeric products to enhance a variety of properties. Under the influences of environmental factors (e.g., ultraviolet, moisture, temperature) and mechanical actions (e.g., scratching

Role of Nanoparticles in Life Cycle of Nanocomposites

June 15, 2010
Xiaohong Gu, Guodong Chen, Minhua Zhao, Stephanie S. Watson, Paul E. Stutzman, Tinh Nguyen, Joannie W. Chin, Jonathan W. Martin
The objective of this study is to investigate the role of ZnO nanoparticles in the life cycle of a waterborne polyurethane (PU) nanocomposite during UV exposure. The effects of loadings and sizes of ZnO nanoparticles on photodegradation of ZnO/PU films

Degradation and Nanoparticle Release of Nanocomposite Coatings Exposed to UV Radiation

June 2, 2010
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Xiaohong Gu, Justin M. Gorham, Paul E. Stutzman, Alexander J. Shapiro, Walter E. Byrd, Joannie W. Chin
The release of nanoparticles from nanocomposite coatings during their life cycle potentially has negative effects to the environments and presents a roadblock to their uses. The degradation and nanoparticle release of amine-cured epoxy coatings containing

Direct Evidence of Nanoparticle Release from Epoxy Nanocomposites Exposed to UV Radiation

April 14, 2010
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Xiaohong Gu, Justin M. Gorham, Paul E. Stutzman, Alexander J. Shapiro, Walter E. Byrd, Joannie W. Chin
This study assessed the fate of SiO2 nanoparticles (nanoSiO2) in epoxy/nanoSiO2 composites exposed to ultraviolet (UV) radiation. The matrix was a stoichiometric mixture of adiglycidyl ether of bisphenol A epoxy and an aliphatic tri-amine. Films of