Title

Chemical modifications of polymer adhesive systems and surface characterization of metal impregnated activated carbons

Date of Completion

January 1995

Keywords

Chemistry, Physical|Chemistry, Polymer

Degree

Ph.D.

Abstract

The chemistry that occurs at a surface is of primary importance in a great number of applications. This thesis examines two systems, both of which involve the determination of the chemical environment at a surface. The first system studied was the chemical modification of various polymers by both chemical etchants and reactive plasmas in order to modify their surface properties. The second system was the characterization of activated carbon particles impregnated with various metal compounds. Similar surface analytical techniques were used to analyze both systems, since both areas of research focused on the upper 100 A of a sample's surface.^ The objective of the polymer surface modification was to chemically alter the surface of various polymers (including polypropylene and polytetrafluoroethylene (PTFE)) using a variety of techniques (radio frequency plasma & sodium naphthalenide chemical etching of the PTFE, and microwave plasma etching of the polypropylene) so as to improve each polymer's wettability and adhesion characteristics. Since little is known about the long term effects of sodium naphthalenide etching on PTFE, this research also investigated the effects of aging and light sensitivity of the sodium naphthalenide etched PTFE surface. The plasma research, while unique in itself, also investigated the in situ chemical vapor treatment of the plasma modified polypropylene surface.^ The objective of the activated carbon characterization was to fully characterize the metal/carbon system in metal impregnated activated carbons. Determining the metal's dispersion throughout the activated carbon granules was accomplished using a combination of SEM and EDX which yielded elemental maps of a sample's surface.^ By looking at whole particles, as well as those cleaved in half to expose the particle's interior, a direct determination was made as to the dispersion of particular elements throughout a particle. Elemental concentrations at the surface (20 to 50 A) were obtained from XPS & AES analysis. These were compared to concentrations in the bulk (1 $\mu$) which were obtained from EDX analysis. The metal's oxidation state, ligand environment and interaction with the carbon support was also obtained from detailed XPS and AES analysis. ^