Dissertation/Thesis Abstract

Surface Modification of Micron-Size Powders by Plasma Polymerization
by Zhang, Ning, M.S., University of Cincinnati, 2000, 143; 10857379
Abstract (Summary)

In our pioneering work, talc (magnesium silicate), mica (aluminum potassium silicate) and silica powders were coated with a thin layer of plasma polypyrrole (PPy) film in a compact RF plasma reactor. Characterization work done on the powders before and after PPy film deposition indicates that plasma polymer film deposition process alters the surface properties of the powders significantly without affecting their bulk properties. It is also shown that the PPy film coated talc and mica powders improve the mechanical strength of polypropylene matrix.

Plasma surface coating of pigment particles was investigated in details using compact RF plasma reactor. Ultrafine pigment particles, Fe2O 3 and Cr2O3, were coated with plasma-polymerized films using several starting monomers. The analysis of plasma polymerized coated pigments of chromic oxide and iron oxide has shown that surface coating of pigments can make a substantial difference to their behaviors.

In our further work, a bench-top size tumbler RF plasma reactor that permits uniform surface modification of relatively large amounts of micron-size powdered materials is described in terms of design and construction. Scale-up to even larger batches of powdered materials seems to be feasible. Preliminary experimental data on characterization of the tumbler reactor and the plasma surface modification of micron-size polymer powders in the tumbler reactor are presented. The results show that deposition of plasma polymer film can be achieved at an appreciable rate in the tumbler reactor and plasma distribution is uniform in the action chamber. Coating of fairly large quantities of micron-size powders with a compact plasma polymer film by RF plasma polymer film deposition process can be carried out batchfully at a reasonable rate in the tumbler RF plasma reactor. The coating is uniform over the particle surface and free of pinholes. The surface properties of the micron-size powders had been altered dramatically after such a plasma polymer film deposition process. Possible reasons for the difference in deposition rate of plasma polymer film on flat substrate and powdered substrate are discussed and strategies to enhance deposition rate of plasma polymer film on powders are developed.

Indexing (document details)
Advisor: Ooij, Wim
Commitee:
School: University of Cincinnati
Department: Engineering : Materials Science
School Location: United States -- Ohio
Source: MAI 57/06M(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Materials science
Keywords: Contact angle, Hmdso, Pmma, Tofsims
Publication Number: 10857379
ISBN: 9780438035058
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