Posted in D L Williams, Physical Chemistry, Solvent Blending

Solvent Substitution – Part 2

The Elimination of Flammable, RCRA and ODC Solvents for Wipe Application

by E. P. Lopez, W. E. Moddeman, J. Birkbeck, D. L. Williams, and M.G. Benkovich

Part One of this article examined hydrofluoroether (HFE) and a hydrofluorocarbon (HFC) cleaners currently being considered as potential replacements for flammable solvents. Part Two reports on the cleaning efficacy, short-term and long-term materials compatibility, corrosion, drying times, flammability, environment, safety and health (ES&H) issues and accelerated aging studies are among the tests that are being conducted and that are used to screen candidate solvents, the traditionally used isopropyl alcohol, which serves as the baseline cleaner.

Preliminary cleaning efficacy results as determined by the contact angle indicate that isopropyl alcohol and the HFE solvent are roughly equivalent in the removal of silicone grease, fluorinated grease and a simulated fingerprint contaminant from various metal alloys. On the other hand, the MESERAN and XPS techniques indicate that in general the HFE solvent, as applied on a Kimwipe is not as effective as isopropyl alcohol. However, XPS analysis demonstrated that the HFE solvent was at least as effective as isopropyl alcohol for removing the simulated finger print contaminant when wiped with a pre-moistened cloth. This article also elaborates on the operational benefits of using the HFE and HFC cleaners.

Published via CleanTech Magazine, 4(10); 14-16 (2004)

About the Authors: E. P. Lopez is from Sandia National Labs, W. E. Moddeman, J. Birkbeck, and D. L. Williams (now at SHSU) are from BWXT Pantex, (Amarillo), and M. G. Benkovich is from Honeywell, (Kansas City). Author’s Note: Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Dept. of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Requests for a pdf reprint can be made to williams “at” shsu “dot” edu.

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Posted in D L Williams, Physical Chemistry, Solvent Blending

Solvent Substitution – Part 1

The Elimination of Flammable, RCRA and ODC Solvents for Wipe Application

by E. P. Lopez, W. E. Moddeman, J. Birkbeck, D. L. Williams, and M.G. Benkovich

In recent years, efforts have been made within the nuclear weapons complex (National Nuclear Security Administration) of the Department of Energy (DOE) to replace Resource Conservation and Recovery Act (RCRA) regulated solvents, (flammable, toxic, corrosive and reactive) and ozone-depleting chemicals (ODC) with more benign alternatives.

Within the National Nuclear Security Administration (NNSA) and the Department of Defense (DoD) sectors, these solvents are used for cleaning hardware during routine maintenance operations. A primary goal of this study featured in this article is to replace flammable solvents for wiping applications.

Sandia National Laboratories, the BWXT Pantex Plant, the Honeywell Kansas City Plant, and other National Nuclear Security Administration (NNSA) sites have teamed to identify suitable replacements for Resource Conservation and Recovery Act (RCRA) solvents and ozone-depleting chemicals (ODC) used in nuclear maintenance operations.

Part one of this article examines two cleaners including a hydrofluoroether (HFE) and a hydrofluorocarbon (HFC) currently being considered as potential replacements for flammable solvents. Cleaning efficacy, short-term and long-term materials compatibility, corrosion, drying times, flammability, environment, safety and health (ES&H) issues and accelerated aging studies are among the tests that are being conducted and that are used to screen candidate solvents. Part two, appearing in the October issue features the results, which are compared to the traditionally used isopropyl alcohol, which serves as the baseline cleaner.

Published via CleanTech Magazine, 4(9); 16-19 (2004)

About the Authors

E. P. Lopez is from Sandia National Labs, W. E. Moddeman, J. Birkbeck, and D. L. Williams (now at SHSU) are from BWXT Pantex, (Amarillo), and M. G. Benkovich is from Honeywell, (Kansas City). Author’s Note: Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Dept. of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Requests for a pdf reprint can be made to williams “at” shsu “dot” edu.

Posted in D L Williams, Physical Chemistry

New Blog Started

I will be posting some of my shorter pieces on this blog.  These may be tutorials or experimental results that are not complete enough for publication. 

About the Author:

Dr. Darren L. Williams (pchem4u) is an Associate Professor of Physical Chemistry at Sam Houston State University.  When he is not blending solvents, he is tinkering with contact angle measurements, FTIR microspectroscopy, etc. http://www.shsu.edu/~chm_dlw/ .  He welcomes your comments and questions by phone (936-294-1529) and by email [williams “at” shsu.edu] done to prevent spambots from finding my email address on this page.