Surface Modification of Glassy Polymeric Carbon by Glow Discharge
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0929-II04-03
Surface Modification of Glassy Polymeric Carbon by Glow Discharge Volha Abidzina1, I. Tereshko1, I. Elkin2, R.L. Zimmerman3, I. Muntele3, C. Muntele3, R.A. Minamisawa3, B. Chhay3, and D. Ila3 1 Belarusian-Russian University, Prospect Mira 43, Mogilev, 212005, Belarus 2 'KAMA VT' Research and Production Enterprise, Karl Libknecht Str. 3a, Mogilev, 212000, Belarus 3 Center for Irradiation of Materials, Alabama A&M University, Normal, AL, 35762-1447 ABSTRACT
We have studied the effects of low energy ion beam produced by glow discharge on glassy polymeric carbon (GPC) produced at pyrolysis temperature ranging from 200C to 1000C. The pristine and irradiated GPC were studied using FTIR, Raman Spectrometry indicating changes at the surface of the GPC samples. INTRODUCTION
Glassy Polymeric Carbon (GPC) is made from cured phenolic resins by heattreatment in inert environment. During the carbonization, increasing the heat treatment temperature, chemical changes take place that eliminate noncarbon elements by diffusion while aromatic rings condense to form graphitic lamellar layers. The final structure of GPC is composed of these graphitic layers in random arrangement with uncorrected pores between them and the material appears dark, hard and vitreous [1]. GPC is an impermeable isotropic carbon material and it can be fabricated with high purity. Due to its chemical inertness and biocompatibility, GPC is useful for medical application such as heart valves and other prosthetic devises [2]. It was shown that MeV ion bombardment significantly enhances the surface roughness and porosity of the partially and fully precursor phenolic resins [3]. MeV bombardment by ions such as silicon, carbon, oxygen and gold increases the hardness of GPC [4]. The increase in hardness is greater for carbon bombardment and it is a result of increased linkage between the chain of the polymeric material, which is due to the recombination of broken bonds or the generation of free radicals by the process of bombardment with energetic ions. GPC is also used for the harsh environment of space as well as for protective coating against extreme environments such as high temperature, highly ionizing radiation, as well as corrosive environment. Therefore we conducted this investigation on the influence of low energy ion irradiation.
EXPERIMENTAL METHODS GPC samples were prepared at the pyrolysis temperatures of 200, 550 and 1000oC [5,6]. After curing at 60oC the resin is pyrolyzed at low temperature rates to avoid changing shape or disruption due to production of volatile gases. Heat treatment to 550 oC produces a conducting material due to hydrogen release and conjugation of the aromatic rings forming graphene planes in random arrangement. Even at 650oC pyrolysis temperature, the material has high level of available pores. Further heat treatment to 1000oC shows reducing permeability as the graphitic planes aggregate random grapheme planes. Before the irradiation in glow-discharge plasma some of GPC samples were coated with Au or Ti. GPC sample
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