Skip to main content
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.

Publications

Search Publications by David VanderHart

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 68

MALDI-TOF MS Characterization of Covalent Cationized Polyethylene

August 1, 2003
Author(s)
Sheng Lin-Gibson, D L. Brunner, David L. VanderHart, Barry J. Bauer, B M. Fanconi, Kathleen M. Flynn, William E. Wallace
MALDI-TOF MS generally uses metal salts to cationize synthetic polymers, such as polystyrene. However, reduced analyte signal often results from complications during the metal ionization processes in the gas phase including competition between the analyte

MALDI MS Characterization of Covalent Cationized Polyethylene

August 1, 2002
Author(s)
Sheng Lin-Gibson, D L. Brunner, David L. VanderHart, Barry J. Bauer, B M. Fanconi, Kathleen M. Flynn, William E. Wallace
Polyolefins, saturated hydrocarbon polymers such as polyethylene (PE) and polypropylene, are, by production volume, the most widely used of all A new method for the mass spectrometry of saturated polyolefins whereby an organic cation is covalently bonded

Optimizing the Covalent Cationization Method for the Mass Spectrometry of Polyolefins

August 1, 2002
Author(s)
Sheng Lin-Gibson, L Brunner, David L. VanderHart, Barry J. Bauer, B M. Fanconi, Charles M. Guttman, William E. Wallace
Previously a new method was introduced for the mass spectrometry of polyolefins whereby an organic cation is covalently bonded to the polymer to produce the necessary ionization for the creation of intact gas?phase macromolecules by matrix-assisted laser

NIST-Sponsored Interlaboratory Comparison of Polystyrene Molecular Mass Distribution Obtained by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry: Statistical Analysis

March 1, 2001
Author(s)
Charles M. Guttman, S Wetzel, William R. Blair, B M. Fanconi, Kathleen M. Flynn, R J. Goldschmidt, William E. Wallace, David L. VanderHart
Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) is becoming a new and important technique in synthetic polymer characterization. Yet much is still unknown about the molecular mass distribution (MWD) which is

Morphological Partitioning of Ethylene Defects in Random Propylene-Ethylene Copolymers

August 1, 2000
Author(s)
R G. Alamo, David L. VanderHart, Marc R. Nyden, L Mandelkern
A series of four propylene/ethylene, metallocene-catalyzed copolymer samples, with ethylene mole fractions ranging from 0.8 to 7.5 mol % and melt-crystallization histories of cooling at 1 C/min, were studied by 13C solid state NMR techniques. The principal