Type of Document Dissertation Author Commerçon, Pascal URN etd-08232007-112115 Title Surface characterization of plasma treated carbon fibers and adhesion to polyethersulfone Degree PhD Department Materials Engineering Science Advisory Committee
Advisor Name Title Dillard, John G. Committee Chair Wightman, James P. Committee Chair Reifsnider, Kenneth L. Committee Member Ward, Thomas C. Committee Member Wilkes, Garth L. Committee Member Keywords
Date of Defense 1992-08-05 Availability restricted AbstractA series of RF plasmas was chosen to modify the surface chemical composition of Hercules IM7 carbon fibers. A two-liquid tensiometric method was used to determine the surface energy parameters y(ds) and I(psf) of the fibers. An XPS analysis of air and argon plasma treated fibers indicated a significant surface oxidation of the fibers which translated into low y(ds) values and high I(psf)values. An ammonia plasma was shown to remove an outer layer from the surface of the fibers. It also increased y(ds) compared to as-received fibers without affecting the non-dispersion (IPsf) XPS results indicated that methane and ethylene plasmas deposited a layer of low surface energy hydrocarbon on the fiber surface. A trifluoromethane plasma and a tetrafluoromethane plasma introduced a significant amount of fluorine containing groups in the fiber surface in the form of a fluorinated plasma polymer in the first case and through direct attack of the fiber surface by fluorine atoms in the second case.
The surface chemical composition and the surface energy parameters of two series of commercially treated carbon fibers were also determined and compared to the results on IM7 carbon fibers.
The adhesion of carbon fibers to polyethersulfone (PES) was measured by using the microbond pull-out test, and compared to the adhesion of the same fibers to an epoxy resin. The load required to debond the microdroplet was used as a measure of the bond strength.
The data were also analyzed in terms of interfacial fracture energy accordIng to the model developed by Jiang and Penn (1992). The microbond pull-out test results showed no significant relation between the fiber surface chemical composition or the fiber surface energy, and the adhesion to PES. However, plasmas which have a strong ablative character such as the ammonia and the tetrafluoromethane plasmas did improve the fiber-PES adhesion, when compared to as-received fibers. The study of the fiber-epoxy systems revealed that a chemical effect contrlbuted to the adhesion improvement but to a lesser extent than the "cleaning" effect of the surface treatment. The results support the two part mechanism proposed by Drzal and extend its application to carbon fiber-thermoplastic systems, but in this case the chemical effect is minimal.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access LD5655.V856_1992.C665.pdf 18.53 Mb 01:25:47 00:44:07 00:38:36 00:19:18 00:01:38next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
If you have questions or technical problems, please Contact DLA.